Land Hermit Crab Research

External Anatomy of Anomura

2006-03-11T18:53:00.000-08:00

External Anatomy of Anomura
The image shows the external anatomy of the hermit crab. It constantly cleans the antenna 1 by the third maxillipeds. The compound eyes are supported by eyestalks which detect movement of an object from a distance.

Each pereopod consists of five articles: Coxa, Basis-ischium, Merus, Carpus, Propodus, and Dactyl. In case of emergency, it autotomizes pereopods between basis and ischium.

--

Arthropoda < Crustacea < Decapoda < Anomura < Paguridae
Hermit crab (Pagurus lanuginosus) is an omnivorous marine animal that utilizes shells for the protection of its abdomen. When it is attacked by predators, it withdraws its body in the shell and defends itself by firmly clinging to the shell by fourth and fifth pereopods, and blocks the hands of predators by the right cheliped.

Pagurus lanuginsus
Hermit Crab
March 2003, Tokyo Bay, Japan
The photo shows the lateral view of a hermit crab (Pagurus lanuginosus). The body structure of Anomura is somewhat asymmetrical. The abdomen, which is normally protected by the shell, winds clockwise where pleopods are attached on one sidef. The right cheliped is larger than the left cheliped. The cheliped carries a pair of movable and immovable fingers. It runs sideways and forward by second and third pereopods. Its cephalothorax is covered with anterior and posterior carapaces. The anterior carapace is hard whereas the posterior carapace is soft and covers the gills underneath.

Lateral View of Pagurus lanuginsus
The photo shows the dorsal view of the hermit crab. The five pairs of legs are shown in the photo (Decapoda, ten legs). The red-orange second antenna is characteristic feature of this species (Pagurus lanuginosus).

Dorsal View of Pagurus lanuginsus
The photo shows the ventral view of the hermit crab (male). The abdomen is soft and covered by thin membrane. At the end of the abdomen, a pair of uropods function as an anchor that hangs on the shell.

Ventral View of Pagurus lanuginsus
The mouth is located between the pairs of maxillipeds. There are three pairs of maxillipeds.

Pagurus lanuginsus Eating Dried Fish January 2004, Chiba, Japan
External Anatomy of Anomura
The image shows the external anatomy of the hermit crab. It constantly cleans the antenna 1 by the third maxillipeds. The compound eyes are supported by eyestalks which detect movement of an object from a distance.

Each pereopod consists of five articles: Coxa, Basis-ischium, Merus, Carpus, Propodus, and Dactyl. In case of emergency, it autotomizes pereopods between basis and ischium.

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Erica Asai
Last Modified: Tue Dec 14 01:44:09 2004

Pet Authority Acidophiliz+

2005-06-27T21:43:00.000-07:00

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BBC NEWS | Science/Nature | Pilfering crab has insect's nose

2005-06-26T08:58:00.000-07:00

BBC NEWS | Science/Nature | Pilfering crab has insect's nose: "Pilfering crab has insect's nose
Robber crab (birgus latro), Current Biology
The robber crab climbs trees to pinch coconuts Image: Current Biology
A land crab re-invented key features of the insect nose over millions of years - a striking example of convergent evolution, Current Biology reports.

An animal's sense of smell needs to operate under very different conditions in air compared with water.

The crab has achieved this in the same way as the ancestors of insects did.

The robber crab, which is descended from marine crabs, had to develop a new way of smelling things when it moved out of the sea and on to land.

Insects evolved some 438-408 million years ago, from an ancestor that also crawled out of water into an air-filled terrestrial environment.

Aggressive opportunist

Convergent evolution describes the situation when animals that are distantly related - like the robber crab and an insect - can evolve similar adaptations in response to natural selection.

Robber crab (birgus latro), Current Biology
They are strong, aggressive opportunists
Marcus Stensmyr, of the Swedish University of Agricultural Science, and colleagues observe that the crab's insect nose 'nicely illustrates how similar selection pressures result in similar adaptation'.

Robber crabs (Birgus latro) are the world's largest land-dwelling arthropods, reaching a length of more than half a metre and a weight of 4kg.

Found on islands from the Indian Ocean to the central Pacific, these aggressive, nocturnal scavengers are known for their ability to climb tall palm trees in search of coconuts - which they later crack open with their massive claws.

The crabs are fully adapted to life on land and will actually drown if submerged in water.

Long-distance attraction

The team studied robber crabs from Christmas Island in Australia. Islanders describe the crabs as 'highly inquisitive' and say they will steal"

Volume 76, No. 5, pp. 513--640, 2003

2005-06-24T21:59:00.000-07:00

Volume 76, No. 5, pp. 513--640, 2003: "Annual migrations and spawning of Coenobita clypeatus (Herbst) on Mona Island (Puerto Rico) and notes on inland crustaceans
Ángel M. Nieves-Rivera & Ernest H. Williams, Jr. 547"

Ocean City sitting pretty with Miss Crustacean

2005-06-24T01:50:00.000-07:00

Cape May County News: The Press of Atlantic City: "June 23, 2005

Ocean City sitting pretty with Miss Crustacean
By MICHAEL MILLER Staff Writer, (609) 463-6712, E-Mail

OCEAN CITY - While Miss America's TV ratings have never been worse, the star is rising for an Ocean City spoof of the famous pageant.

The Miss Crustacean Pageant - scheduled for Aug. 3 - was featured this month in Newsweek's summer calendar. City spokesman Mark Soifer said he has fielded phone calls so far from Spin Magazine, ESPN the Magazine and Ripley's Believe it or Not! about this uniquely Ocean City contest in which children show off the hermit-crab dioramas they build.

The winner's crab is crowned 'Miss Crustacean' and is paraded in front of a large crowd at the Sixth Street beach to the tune, 'There she is, Miss Crustacean.' The winner gets the Cucumber Rind Cup - a trophy with an actual cucumber, a preferred food of hermit crabs.

The Miss America Organization still has no TV contract for this year's pageant. The show's ratings have steadily declined despite efforts to make the contest more relevant and appealing to viewers.

Meanwhile, Ocean City's gentle satire has become an August hit - at least among media looking to liven up dreary summer news packages, Soifer said.

'Miss Crustacean is getting more publicity than ever. It's listed in the mag azines that go out to radio stations for filler. That's what it is, filler,' Soifer said unapologetically.

Soifer is the publicity mastermind behind both the contest and the city's crab mascot, Martin Z. Mollusk. The hermit crab presides over the pageant, a 30-year tradition in Ocean City.

The children's displays have spoofed TV shows such as 'Survivor' and national politics. Some local businesses compete in the commercial division.

Old Salt is a perennial winner. This Boardwalk gift store displays its Cucumber Rind Cups near the hermit crabs it sells for $2 to $6.

'If you have a really good idea and your"

Respiration in Coenobita

2005-06-23T13:06:00.000-07:00

The Crab Street Journal: "Respiration

'The land hermit crabs (genus Coenobita) have been the focus of several respiratory studies but remain difficult to categorize. These crabs may be found some kilometers from the sea (De Wilde, 1973; see also Chapter 3 and the Appendix). At first sight they appear highly terrestrial. A closer look at the level of respiratory adaptation, however, creates confusion, revealing some features clearly similar to the more terrestrial crabs and some similar to less terrestrial forms. Morphologically, the gills are substantially reduced, indicating a low dependence on water. However, the branchial chambers are not enlarged, nor are the branchiostegal walls particularly modified (section 2). Thus, these crabs are apparently not clearly modified for aerial respiration. Coenobita spp. do not voluntarily immerse themselves in water, but a single report of MO2 in C. scaevola submerged in the laboratory (Achituv and Ziskind, 1985) indicates that acquatic MO2 can beincreased above that recorded for animals resting in air, at least in the short term. While this increase probably results from the increased acctivity seen in immersed animals, it does show that resonable O2 updake can occur in submerged animals despite a severely reduced gill area (Table 8.1)

Hemolymph O2 capacities in this group are among thehighest reported for Crustacea, a feature that could be regarded as highly terrestrial. However, the high O2 capacity is coupled with the lowest O2 pressures recorded (in air) in any land crab (Fig. 8.6; Table 8.5). This observation, coupled with the poor development of aerial-gas exchange surfaces, may indicate that these crabs normally conduct a large part of gaseous exchange across the gills despite their apparatus terrestriality. The extremely high O2 capacity of this hemolymph may thus be an adaptation to a very high diffusion limitation occuring accross a generally reduced gas-exchange surface. An"

Clustering in hermit crabs

2005-06-23T12:06:00.000-07:00

Untitled Document: "Clustered arrangements of organisms, created by social interactions, are promoted by the patchy distribution of resources (Molles, 1999). This clustering is a result of social facilitation to increase the efficiency of resource attainment. Clusters are defined as groups of 50-5000 animals resting in physical contact with each other (Gherardi and Vannini, 1993).

Clustering in hermit crabs has been shown to be commonplace among Diogenidae and Paguridae in tropical and temperate environments and in varied habitats (Gherardi and Vannini, 1993). Hermit crabs of the genus Clibanarius have been previously analyzed due to this conspicuous habit. These crabs can be observed moving around the cluster and performing social activities in their intertidal habitat (Gherardi, Zatteri, Vannini, 1994). Indeed, it has been shown that the primary functions of the aggregations of crabs are to facilitate social activities such as the exchange of shells and exploitation of food resources (Gherardi and Vannini, 1993; Barnes and Arnold 2001).

Shells are a limiting resource for which hermit crabs must compete, often becoming so scarce that crabs are often forced to utilize shells that are too small or otherwise (Floeter et al, 2000). The overall adaptive fitness of hermit crabs is decreased when crabs are prevented from obtaining an adequate shell. Not only does having an adequate shell protect the crab from predation and physical stress (Bertness, 1981), it facilitates growth and reproductive activities. Growth is limited by shell adequacy, becoming faster when shells are not a limiting resource (Turra and Leite, 2000). Because inadequate shells retard growth, female crabs that cannot grow in their shells switch energy allocation to immediate reproduction, resulting in smaller clutch sizes (Turra and Leite, 1999).

Hermit crabs are highly selective in their search for adequate shells. This often results in the acquisition"

Ecological Importance of Terrestrial Hermit Crabs in the Galapagos Islands

2005-06-23T11:15:00.000-07:00

Ecological Importance of Terrestrial Hermit Crabs in the Galapagos Islands: "Ecological Importance of Terrestrial Hermit Crabs in the Galapagos Islands
SALLY E. WALKER (Dept. of Geology, University of Georgia, Athens, GA 30602)
Terrestrial hermit crabs are ubiquitous on tropical islands; however, their ecology is poorly known. This research was undertaken under the auspices of the Charles Darwin Research Foundation and the Galapagos National Park to determine the species of terrestrial hermit crabs that occur on the Galapagos Islands and their ecology in relation to the human population on Santa Cruz Island. The human impacted sites of Director´s Beach and Tortuga Bay and the protected site of Puerto Nuñez were used in this study. Coenobita compressus was the only species encountered. Thais melones was the most commonly used shell at Director’s Beach (54%) while Nerita scabricosta was used by 65% of the hermits at Tortuga Bay and by 75% at Puerto Nuñez. At the human-affected sites, C. compressus emerged 1 to 1.5 hours after sunset to forage on bananas, corn cobs, bread, and grapefruit which were discarded by tourists. Crabs were afraid of humans at these localities, stopping behavior upon approach. At the protected site, crabs appeared two hours before sunset and were not afraid of humans — continuing with mating, aggressive behavior and food foraging. They consumed the purple flowers of Sesuvium, leaves of Tiquilia galapagoa, and foraged within driftwood and mangrove litter. However, the crabs were attracted to the camp garbage and ate the plastic garbage bag, paper labels off the cans, and 'papeles de higenico'. In summary, these 'Cangrejos de Basura' are indeed important organisms for maintaining the cleanliness of Galapagos beaches with their late night beach-sweeping activities.

Citation:

Walker, S.E. 1999. Ecological importance of terrestrial hermit crabs in the Galapagos Islands. Proceedings of the American Association for the Advancement"

Salt and water balance and antennal gland function

2005-06-23T11:13:00.000-07:00

Identification guide - Mangrove literature: "Harris, RR and GA Kormanik, 1981. Salt and water balance and antennal gland function in three Pacific species of terrestrial crab (Gecarcinus lateralis, Cardisoma carnifex, Birgus latro). II. The effects of desiccation. Journal of Experimental Zoology 218: 107-116."

Acid-base responses to changes in CO2 in Coconut Crabs

2005-06-23T11:12:00.000-07:00

Identification guide - Mangrove literature: "Cameron, J.N., 1981. 'Acid-base responses to changes in CO2 in two Pacific crabs: the coconut crab Birgus latro, and a mangrove crab, Cardisoma carnifex.' Journal of experimental Zoology 218:65-73."

Assessment of the status of the coconut crab Birgus latro on Niue Island

2005-06-23T11:07:00.000-07:00

ASFB Member’s Bibliography: "Schiller, C.B. 1992. Assessment of the status of the coconut crab Birgus latro on Niue Island with recommendations regarding an appropriate resource management strategy. Consultancy report. Food and Agriculture Organisation of the United Nations, Rome. 69pp."

The Coconut Crab: Reproduction, early life-history and recruitment

2005-06-23T11:06:00.000-07:00

ASFB Member’s Bibliography: "Schiller, C.B., Fielder, D.R., Brown, I.W. and Obed, A. 1991. Reproduction, early life-history and recruitment. pp. 13-33. In, Brown, I.W. and Fielder, D.R. (eds.). The Coconut Crab: Aspects of the biology and ecology of Birgus latro in the Republic of Vanuatu. ACIAR Monograph 8, Canberra."

population structure and evolutionary history of the coconut crab

2005-06-23T11:03:00.000-07:00

HistCite - index: JC Avise: "3932 31 76 4004 1996 AUG [15] MOLECULAR ECOLOGY 5(4):557-570
Lavery S; Moritz C; Fielder DR
Indo-Pacific population structure and evolutionary history of the coconut crab Birgus latro
36 45"

Coconut crab - Iridis Encyclopedia

2005-06-23T11:01:00.000-07:00

Coconut crab - Iridis Encyclopedia: "Coconut crab

The Coconut crab (Birgus latro) is the largest terrestrial arthropod, known for its ability to crack coconuts with its strong pincers in order to eat the contents. The crab is sometimes called the Robber Crab or Palm Thief (in German), because some crabs steal shiny items such as pots and silverware from houses and tents. Another name is the terrestrial hermit crab, due to the use of shells by young crabs. The crab also has different local names as for example Ayuyu in Guam, or Unga or Kaveu.

The crab's range includes the Indian and western Pacific ocean. The crabs differ slightly in color among different islands, ranging from light violet to deep purple, to brown.
Species

The coconut crab is the largest terrestrial crab. The body length can grow up to 40 cm (16 inches), with a weight of up to 4kg (9 pounds) and a leg span of 1 meter (3 feet), with males being larger than females. (The largest crab overall is the Japanese spider crab, with a leg span of almost 4 meters (13 feet).) The body of the coconut crab is, like most hermit crabs, roughly divided into a front section and an abdomen. The crab has 10 legs. The front most legs have massive pincers used to open coconuts. These claws have been measured to lift objects up to 29 kg (64 lbs) in weight. The next three pairs have smaller tweezers at the end which allow the crab to move quite easily along terrestrial surfaces. In addition these specially adapted limbs enables them to climb verticaly up trees (often coconut palms) up to 6m high. Crabs face skyward while climbing either up or down. The legs may also be used to handle food. The last pair of legs is very small and serves only to clean the breathing organs. Usually, these legs are held inside the body in the cavity containing the breathing organs. The print below shows these small legs extended to the side.

The crab belongs to the class of Hermit crabs, however, it may be difficult for large adults t"

Zoology Unlimited, Endangered Species Surveys

2005-06-23T11:00:00.000-07:00

Zoology Unlimited, Endangered Species Surveys: "Coconut Crab

Found throughout the western Pacific and eastern Indian Oceans, the coconut crab (Birgus latro) appears to be mainly restricted to islands. Closely related to hermit crabs, the adult does not require a mollusk shell for protection and only returns to the ocean to release its larvae (Amesbury 1980 – Tech. Report No. 17, University of Guam). Otherwise it lives a purely terrestrial existence scavenging in the forest. Older crabs usually have an established burrow, and they are quite capable of climbing trees. Coconut crabs can grow quite large, to 4kg, and ages in excess of 50 years have been suggested. Like all crabs it must periodically shed its exoskeleton. This is done underground and can last a month or more (Brown & Fielder (eds.) 1991-ACIAR Monograph No. 8). They have been found to be diurnal on islands with no human occupation and nocturnal on islands with humans.

Coconut crabs are gathered for consumption throughout their range. They are easily caught by hand and require no specialized equipment other then a coconut for bait. These qualities have resulted in adverse impacts on populations that occur on islands with human populations. This has prompted wildlife departments to try various management techniques based on established methods for other species. Good scientific data is lacking on this species and further studies are needed to determine conservation needs. Because of the excellent quality of it taste, many have looked at the feasibility of raising crabs. Unfortunately this seems improbable due to the quarrelous nature of the crabs and the long period required reaching a harvestable size.
Happy crab.jpg (38207 bytes) crab transmitter.jpg (64287 bytes)
Happy Gideon with coconut crab on Anatahan Island Coconut crab with radio transmitter - Saipan

The coconut crab, or ayuyu, is an important food species in the Commonwealth of the Northern Mariana Island"

robber crab and an insect --can evolve similar adaptations in response to natural selection

2005-06-23T10:36:00.000-07:00

EVOLUTION & GENETIC NEWS, Gaia Church: "A land crab re-invented key features of the insect nose over millions of years --a striking example of convergent evolution, Current Biology reports. An animal's sense of smell needs to operate under very different conditions in air compared to water. The crab has achieved this in the same way as the ancestors of insects did. Insects evolved some 438-408 million years ago, from an ancestor that also crawled out of water into an air filled-terrestrial environment. The robber crab, which is descended from marine crabs, had to develop a new way of smelling things when it moved out of the sea and on to land.
. . Convergent evolution describes the situation when animals that are distantly related - like the robber crab and an insect --can evolve similar adaptations in response to natural selection.They observe that the crab's insect nose "nicely illustrates how similar selection pressures result in similar adaptation "

Smelling organs of robber crabs (Birgus latro) are called aesthetascs

2005-06-23T10:33:00.000-07:00

EVOLUTION & GENETIC NEWS, Gaia Church: "Robber crabs (Birgus latro) are the world's largest land-dwelling arthropods, reaching a length of more than half a metre and a weight of 4kg. The crabs are fully adapted to life on land and will actually drown if submerged in water.
. . The smelling organs of robber crabs are called aesthetascs. These are mounted on paired antennae, or antennules. In the robber crab, these smelling organs share many features with insect olfactory organs called sensilia - including a short, blunt shape. The crab's aesthetascs were very different to those of marine crabs."

Search Results

2005-06-23T10:17:00.000-07:00

Search Results: "Ghiradella, H., Case, J., Cronshaw, J. 1968 Fine structure of the aesthetasc hairs of Coenobita compressus Edwards. J. Morphol. 124: 361-385."

Locomotion and hermit crabs

2005-06-15T08:14:00.000-07:00

Library H: endnote: "Herreid II, C. F. and Full, R. J. (1986). Energetics of hermit crabs during locomotion: the cost of carrying a shell. J. exp. Biol. 120, 297-308.

Herreid II, C. F. and Full, R. J. (1986). Locomotion of hermit crabs (Coenobita compressus) on beach and treadmill. J. exp. Biol. 120, 283-296.

Herreid II, C. F. and Full, R. J. (1988). Energetics and locomotion. In Biology of the Land Crabs (ed. W. Burggren and B. R. McMahon), pp. 333-377. New York: Cambridge University Press."

News 14 Carolina | 24 Hour Local News | SLIDESHOWS

2005-04-15T09:21:00.000-07:00

News 14 Carolina | 24 Hour Local News | SLIDESHOWS: "Pet Pictures (4/11 – 4/22)
In conjunction with the upcoming Animal Planet Expo in uptown Charlotte, News 14 is holding a pet photo contest.

We want to see your favorite picture and a short note about how your pet has enriched the lives of your family. Please keep the e-mails to less than 100 words.

Click Here to Send a Picture

Pet Picture Entries (1) (2)
Photo Examples"

2005-04-14T00:47:00.000-07:00

Several members of CSJ (especially Daethian) have been uploading photos of their seashells. If you ae trying to ID your crab's favourite seashell, this may be the place to go!

Dandelion Root

2005-04-14T00:43:00.000-07:00

Dandelion Root: "Dandelion Root (Taraxacum Officinale) is naturally rich in potassium has been used traditionally as a liver tonic, diuretic, and blood cleanser; helpful for treating water retention, inflammation, and congestion and disorders of the liver and gallbladder. Nature's Herbs Wild Countryside Dandelion Root grows in rich fertile meadows of Europe. This unwelcome inhabitant of lawns is actually quite beneficial for the body, American Indians combined the Dandelion Leaves with the Roots (which are said to contain more vitamin A than carrots) to brew a healthy herbal tea."

Mysis Relicta -- Natural fish food,for finicky saltwater and freshwater fish, by Piscine Energetics

2005-04-14T00:40:00.000-07:00

Mysis Relicta -- Natural fish food,for finicky saltwater and freshwater fish, by Piscine Energetics: "Mysis are considered a part of the zooplankton, the small invertebrate animals found in all lakes that feed on microscopic algae (phytoplankton) as well as other zooplankton. In turn these organisms form the basis of the food supply for many fish. There are however, two major differences between Mysis and the other zooplankton typically found in lakes. First, Mysis have a longer lifespan. The typical zooplankton, composed of animals known as copepods, cladocerans and rotifers, live anywhere from only several days to several months. In our lakes, populations of these animals may complete a number of generations in the course of a year. Usually they become very abundant during the summer months and very sparse during the winter.

Mysis on the other hand, usually live two years. Adults breed during the winter. The young are carried in the brood pouch until late spring or early summer when they are then released to grow for another year and a half before they breed and complete the life cycle.

The second difference is size. Mysis range in size from newly released young of about one-eight inch to adults of up to 3/4 inch. The other zooplankton are normally much smaller ranging from one one-hundredth to one tenth of an inch in total length.

It is the size of the Mysis that makes them of interest as a fish food.The picture shown here is magnified several times with the tip of a small skewer as a reference.

Because they are much larger than the zooplankton that fish normally feed upon, they are an excellent food item. Fish that consistently feed on Mysis grow much faster than those feeding strictly on the other smaller zooplankton. Mysis are extremely high in nutritional value and are salt free."

Mysis Relicta -- Natural fish food,for finicky saltwater and freshwater fish, by Piscine Energetics

2005-04-14T00:38:00.000-07:00

Mysis Relicta -- Natural fish food,for finicky saltwater and freshwater fish, by Piscine Energetics: "
Mysis is a natural product enriched by the food chain of lakes from which it is harvested. There is no artificial enrichment on this product, yet fatty acid profiles are higher than that of enriched brine shrimp. It also has more than three times the fatty acid content as compared to krill. The density of Mysis is greater than that of brine shrimp. This results in less waste when feeding. Mysis is a nutritionally complete food, without enrichment. This is because of Mysis relicta's highly diversified eating habits. The extremely high levels of EPA and DHA (fatty acids) is related to the food chain found in deep cold waters, such as those where Mysis is harvested. These fatty acids not only provide your fish with essential nutrition, but also stimulate a positive feeding response."

2005-03-26T03:53:00.000-08:00

Neat use of PVC pipes for a second level. Kudos to Daethian!

2005-03-13T10:51:00.000-08:00

Recipe Reviews module is in operation! A big thanks to Kerie (aka Julia Crab) for taking on the role of Recipes Mod! I had better not let the crabs see how the other half lives - I could have a crabby mutiny on my hands!

2005-03-13T01:04:00.000-08:00

Indonesian supplier of land hermit crabs and :puke: painted shells

2005-03-13T00:56:00.000-08:00

Memoirs of the Faculty of Science,
Kyoto University Vol.18, No1 (2002) Ecology of the Land Hermit Crab Coenobita purpureus on Kikaijima Island. II. Breeding behavior, Food, Predator, Orientation and the Environment Michio Imafuku 15 Vol.17, No.2 (2001) Ecology of the Land Hermit Crab Coenobita purpureus on Kikaijima Island. I. Breeding Site, Breeding Season and Migration Michio Imafuku 55

Contributions to Zoology

2005-02-28T14:29:00.000-08:00

Contributions to Zoology: "
To refer to this article use this url: http://dpc.uba.uva.nl/ctz/vol67/nr02/a01
Contributions to Zoology, 67 (2) 79-123 (1997)
Carcinization in the anomura - fact or fiction? I. Evidence from adult morphology

Patsy A. McLaughlin 1, Rafael Lemaitre 2

1. Western Washington University, Shannon Point Marine Center. , Anacortes, Washington, U.S.A..

2. National Museum of Natural History, Smithsonian Institution, Department of Invertebrate Zoology. , Washington, D.C., U.S.A..

Keywords: Carcinization, Anomura, Paguroidea, Galatheoidea, Hippoidea, Lomoidea, Paguridae, Lithodidae, adult morphology, phylogeny"

Animals Australia federation of animal welfare and animal rights :: Fish and Crustaceans

2005-02-28T01:32:00.000-08:00

Animals Australia federation of animal welfare and animal rights :: Fish and Crustaceans

2005-02-23T19:09:00.000-08:00

ACETAMINOPHEN FEEDING TESTS IN LAND HERMIT CRABS (Coenobita brevimanus) AND COCONUT CRABS (Birgus latro)
SAVARIE, P. J., T. J. LINDER, and D. L. YORK
USDA, National Wildlife Research Center, 4101 LaPorte Ave., Fort Collins, CO 80521-2154
Acetaminophen is a widely consumed over-the-counter analgesic drug and it is an effective oral toxicant for brown treesnakes (Boiga irregularis). However, little is known about its ecotoxicological and non-target effects. Crabs are non-target animals that could be exposed to acetaminophen by feeding on treated baits (primary toxicity) or by feeding on brown treesnakes killed by acetaminophen baits (secondary toxicity). During 2001 under laboratory conditions with individually caged animals, the primary toxicity to land hermit crabs and the primary and secondary toxicity to coconut crabs was assessed. Secondary tests were not conducted with hermit crabs because they did not consume bait prepared from snakes. Toxicity tests contained pre-treatment, treatment, and post-treatment phases with fresh control or treated bait offered daily. Two primary toxicity tests, each with 80 mg (2-40 mg tablets) acetaminophen offered during treatment, were conducted with hermit crabs. In Test 1, acetaminophen was placed in about 1 g of commercially processed meat bait and offered each day for 3 days. In Test 2, acetaminophen was placed in about 1 g of commercially shaved coconut and offered each day for 2 days. No signs of toxicosis or mortality were observed. Results of the primary toxicity test in coconut crabs was similar, with all control and treated crabs surviving. In all the primary toxicity tests, crabs ate the bait matrix but generally avoided eating the control tablets and acetaminophen tablets. In the coconut crab secondary toxicity test, crabs were given a treated bait consisting of ground brown treesnakes for 3 days. Treated bait was prepared from brown treesnakes that died by consuming 160 mg acetaminophen, twice the dose used in field trials. Coconut crabs ate the treated bait but no signs of toxicosis or mortality were observed. These test results indicate that primary and secondary toxicity hazards of acetaminophen to crabs are negligible.

Phylogeny of the Anomura (Decapoda, Crustacea): Spermatozoa and spermatophore morphological evidence

2005-02-03T08:01:00.000-08:00

An interesting article written by Christopher Tudge, which was published several years ago. Well worth a read!

: "Phylogeny of the Anomura (Decapoda, Crustacea): Spermatozoa and spermatophore morphological evidence

Christopher C. Tudge

Museum of Victoria, Crustacean Laboratory. , 71 Victoria Crescent, Abbotsford, Vic. 3067, Australia. E-mail: ctudge@mov.vic.gov.au

Contributions to Zoology, 67 (2) 125-141 (1997)

To refer to this article use this url: http://dpc.uba.uva.nl/ctz/vol67/nr02/a02

A phylogenetic analysis of selected anomuran, thalassinidean, and other decapod crustacean taxa, based on spermatozoal ultrastructural characters and spermatophore morphological characters, was performed and the following relationships of the taxa are elucidated from the trees produced. The Anomura are not a monophyletic assemblage, with the lomoid Lomis being exclusive of the remainder of the anomuran taxa, and the thalassinid Thalassina included in the anomuran clade. The synapomorphy joining the majority of the conventional anomuran taxa (Lomis excluded) is the cytoplasmic origin of the microtubular arms. When the palinurid and thalassinoid representatives are separately designated as outgroups, the Astacidea and Brachyura jointly formed a sister group to the Anomura. The superfamilies Thalassinoidea, Paguroidea, and Galatheoidea are not monophyletic groups. In all analyses the anomuran families Coenobitidae and Porcellanidae each form a monophyletic group. The paguroid family Diogenidae is paraphyletic, with the genera Clibanarius and Cancellus separate from a single clade containing the remaining diogenid genera. The families Paguridae and Parapaguridae form a monophyletic clade with the exception of Porcellanopagurus. The two representatives of the family Chirostylidae (Eumunida and Uroptychus) fail to associate with the other species in the Galatheoidea. The taxa in the family Galatheidae are not a mono"

The Animals May Have Known

2005-01-11T02:23:00.000-08:00

CBS News | The Animals May Have Known | January 10, 2005�12:00:11

Section Front • Section Front

E-mail This StoryE-mail This Story Printable VersionPrintable Version

The Animals May Have Known

KHAO LAK, Thailand, Jan. 10, 2005

Workers walk on foundation of damaged Yala Safari Game Lodge, 125 miles southeast of Colombo, Sri Lanka. Officials expressed surprise they found no evidence of large-scale animal deaths from tsunami (Photo: AP)

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•Dramatic footage on Earthquake And Aftermath

(CBS) So passive, so large and, it seems, so much more attuned to nature's wrath.

Elephants in Khao Lak, the hardest hit area in Thailand, trumpeted in fear a full three hours before the earthquake hit Indonesia, hundreds of miles away.

And then sounded the alarm again, before the tidal wave hit more than an hour after the earthquake.

Some were so agitated, they broke their chains and escaped to higher ground.

The elephants gave some kind of notice. They trumpeted the warning. The irony is that it fell on deaf ears: Humans who heard the warnings did not respond, did not understand the danger that was coming.

An elephant handler, Apichart, says it won't happen to him again. Next time, he told Petersen, when the elephants warn, "We'll all run for the hills."

Across the stricken region, many animals sounded warnings, or fled before the tsunami smashed ashore.

On some islands in Thailand, hermit crabs, who live on the beaches, suddenly scampered to higher ground before the wave hit.

At the fishing village of San Souk, birds started a frantic squawking. Villagers took heed and ran, and all 1,000 of them escaped unharmed.

Dive boat leader Chris Cruz saw the sea erupt with scores of dolphins. "I spoke to the captain," he told Petersen. "I rushed up to him and said, 'We have to follow those dolphins.'"

They were led to water so deep, the wave passed harmlessly underneath.

So, says Cruz, the dolphins saved many human lives.

These days, people expect wailing sirens or loudspeaker warnings of coming disasters. There were none. But nature's warnings were there. Had more people heeded them, so many more might have lived.

©MMV, CBS Broadcasting Inc. All Rights Reserved.

Robber crab.jpg (JPEG Image, 600x450 pixels)

2005-01-07T05:55:00.000-08:00

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2005-01-07T01:52:00.000-08:00

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2005-01-07T01:50:00.000-08:00

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2005-01-07T01:49:00.000-08:00

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Respiratory and Ionic Regulation in Invertebrates Exposed to Both Water and Air

2004-12-28T04:29:00.000-08:00

Annual Review of Physiology - 52(1):61 - PDF: "Respiratory and Ionic Regulation in Invertebrates Exposed to Both Water and Air
J P Truchot
Annual Review of Physiology, March 1990, Vol. 52: Pages 61-74
(doi: 10.1146/annurev.ph.52.030190.000425)"

Socially guided behaviour in non-insect invertebrates

2004-12-28T04:26:00.000-08:00

SpringerLink - Article: "Animal Cognition
Publisher: Springer-Verlag Heidelberg
ISSN: 1435-9448 (Paper) 1435-9456 (Online)
DOI: 10.1007/s100710100108
Issue: Volume 4, Number 2
Date: October 2001
Pages: 69 - 79
Socially guided behaviour in non-insect invertebrates

Sandra J. Webster and Graziano Fiorito

A1 Department of Biology, McGill University, Montr�al, Qu�bec, H3A 1B1, Canada
A2 Stazione Zoologica 'Anton Dohrn', Napoli, Italy
A3 Present address: Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada, e-mail: sandrajwebster@hotmail.com, Tel.: 1-604-291-581, Fax: 1-604-291-3496

Abstract:

Abstract. A review of the past 50 years of literature on socially guided behaviour addresses two questions: (1) whether socially guided behaviour, which has traditionally been considered characteristic of vertebrates, is also found among non-insect invertebrates, and (2) to see whether our classification of socially guided behaviours in invertebrates matches, and thereby supports, A. Whiten and R. Ham's classification of vertebrate behaviours into two broad categories, social learning and social influence. We systematically reviewed the literature on socially guided behaviour in non-insect invertebrates to determine if social behaviours exist. Once this was established, we characterised our findings using 13 behavioural phenomena that are considered to be descriptive of socially guided behaviour. Using a multivariate technique, we then analysed the data to determine if our characterisation scheme produced a similar distribution to that presented by A. Whiten and R. Ham. Our results indicate that socially guided behaviours are present in invertebrates, and invertebrates can be placed into the previously established framework on vertebrate social behaviour. Further, our analysis reveals a promi"

SpringerLink - Article

2004-12-28T04:21:00.000-08:00

SpringerLink - Article
Animal Cognition
Publisher: Springer-Verlag Heidelberg
ISSN: 1435-9448 (Paper) 1435-9456 (Online)
DOI: 10.1007/s100710100108
Issue: Volume 4, Number 2
Date: October 2001
Pages: 69 - 79
Socially guided behaviour in non-insect invertebrates

Sandra J. Webster and Graziano Fiorito

A1 Department of Biology, McGill University, Montréal, Québec, H3A 1B1, Canada
A2 Stazione Zoologica "Anton Dohrn", Napoli, Italy
A3 Present address: Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada, e-mail: sandrajwebster@hotmail.com, Tel.: +1-604-291-581, Fax: +1-604-291-3496

Abstract:

Abstract. A review of the past 50 years of literature on socially guided behaviour addresses two questions: (1) whether socially guided behaviour, which has traditionally been considered characteristic of vertebrates, is also found among non-insect invertebrates, and (2) to see whether our classification of socially guided behaviours in invertebrates matches, and thereby supports, A. Whiten and R. Ham's classification of vertebrate behaviours into two broad categories, social learning and social influence. We systematically reviewed the literature on socially guided behaviour in non-insect invertebrates to determine if social behaviours exist. Once this was established, we characterised our findings using 13 behavioural phenomena that are considered to be descriptive of socially guided behaviour. Using a multivariate technique, we then analysed the data to determine if our characterisation scheme produced a similar distribution to that presented by A. Whiten and R. Ham. Our results indicate that socially guided behaviours are present in invertebrates, and invertebrates can be placed into the previously established framework on vertebrate social behaviour. Further, our analysis reveals a prominent separation between representations of the social influence and social learning categories, thereby supporting the previously published framework on socially guided behaviour.

Keywords:

Social learning, Social influence, Social behaviour, Invertebrates

Studies of male sexual tubes in hermit crabs

2004-12-28T02:59:00.000-08:00

Wiley InterScience: Journal: Abstract
Article
Studies of male sexual tubes in hermit crabs (crustacea, decapoda, anomura, paguroidea). I. Morphology of the sexual tube in Micropagurus acantholepis (Stimpson, 1858), with comments on function and evolution
Christopher Tudge 1 2 *, Rafael Lemaitre 2
1Biology Department, American University, Washington, DC 20016-8007
2Department of Systematic Biology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013-7012
email: Christopher Tudge (ctudge@american.edu tudge.christopher@nmnh.si.edu)

*Correspondence to Christopher Tudge, Biology Department, American University, 4400 Massachusetts Ave. NW, Washington, DC 20016-8007

Funded by:
Australian ARC Postdoctoral Fellowship (1996-1999)

Keywords
sexual tube • hermit crab • Micropagurus • Paguridae • histology • TEM • SEM

Abstract
The external morphology and internal structure of the male sexual tube of the hermit crab Micropagurus acantholepis, a member of the family Paguridae from Australian waters, is described in detail using histological thick sectioning and scanning and transmission electron microscopy techniques. This is the first in-depth study of a sexual tube in the Paguroidea, a group where a remarkable number of genera (55.9% in the family Paguridae) with species having these intriguing sexual structures are known. In M. acantholepis a sexual tube is present on the left side, whereas only a gonopore is present on the right side. The tube is used for the delivery of spermatophores to the female and consists of a sheath of cuticular origin surrounding an internal, functional extension of the posterior vas deferens. Pedunculate spermatophores were observed within the lumen and partially extruding from the terminal opening of the tube in preserved specimens. The tube protrudes from the left coxa of the fifth pereopod as an elongate 3-mm-long, hollow, coiled structure with a terminal opening. Exteriorly the tube consists of a conspicuous thick chitinous cuticular ridge throughout its length, and a thin chitinous cuticle with sparse, regularly arranged simple setae. Interior to the cuticle, the tube contains loose connective tissue, secretory cells, oblique muscle, circular muscle, and epithelial cells. The latter cells line a central lumen that runs the length of the sexual tube. The morphology, cellular composition, and function of the tube are discussed. J. Morphol. 259:106-118, 2004. © 2003 Wiley-Liss, Inc.

Calcium homeostasis in crustacea

2004-12-28T02:57:00.000-08:00

Wiley InterScience: Journal: Abstract: "
Comparative Physiology and Biochemistry
Calcium homeostasis in crustacea: The evolving role of branchial, renal, digestive and hypodermal epithelia
Michele G. Wheatly *
Department of Biological Sciences, Wright State University, Dayton, Ohio 45435
email: Michele G. Wheatly (michele.wheatly@wright.edu)

*Correspondence to Michele G. Wheatly, Department of Biological Sciences, Wright State University, Dayton, OH 45435

Funded by:
NSF; Grant Number: 9603723

Abstract
Crustaceans serve as an ideal model for the study of calcium homeostasis due to their natural molting cycle. Demineralization and remineralization of the calcified cuticle is accompanied by bidirectional Ca transfer across the primary Ca transporting epithelia: gills, antennal gland (kidney), digestive system, and cuticular hypodermis. The review will demonstrate how a continuum of crustaceans can be used as a paradigm for the evolution of Ca transport mechanisms. Generally speaking, aquatic crustaceans rely primarily on branchial Ca uptake and accordingly are affected by water Ca content; terrestrial crustaceans rely on intake of dietary Ca across the digestive epithelium. Synchrony of mineralization at the cuticle vs. storage sites will be presented. Physiological and behavioral adaptations have evolved to optimize Ca balance during the molting cycle in different Ca environments. Intracellular Ca regulation reveals common mechanisms of apical and basolateral membrane transport as well as intracellular sequestration. Regulation of cell Ca concentration will be discussed in intermolt and during periods of the molting cycle when transepithelial Ca flux is significantly elevated. Molecular characterization of the sarco-/endoplasmic reticular Ca pump in aquatic species reveals the presence of two isoforms that originate from a single gene. This gene is differentially expressed during the molting cycle. Gene expression may be regulated "

Wiley InterScience: Journal: Abstract

2004-12-28T02:54:00.000-08:00

Wiley InterScience: Journal: Abstract
Role of the midgut gland in purine excretion in the robber crab, Birgus latro (Anomura: Coenobitidae)
Richard M. Dillaman, Peter Greenaway *, Stuart M. Linton
School of Biological Sciences, University of New South Wales, Sydney, Australia
email: Peter Greenaway (p.greenaway@unsw.edu.au)

*Correspondence to Peter Greenaway, School of Biological Sciences, University of New South Wales, Sydney 2052, Australia.

Funded by:
the Australian Research Council; Grant Number: 942611 (to Peter Greenaway)

Keywords
Birgus latro; Crustacea; midgut gland; uric acid; catalase; xanthine dehydrogenase; land crab

Abstract
White fecal strands of Birgus latro are composed of small spherules of uric acid with a mean diameter of 1.6 ± 0.6 m. Large numbers of membrane-bound spherules with concentric lamellae are present in the R cells of the midgut gland, so we suggest that lengths of white feces are produced by coordinated secretion of these spherules into the lumen of the midgut gland tubules. There are four cell types in the tubules with embryonic (E) cells at the distal tip, B cells in a narrow band at the distal end and R cells making up the bulk of the tubules and gland. F cells are sparsely scattered among the R cells. Midgut gland tissue was assayed for activities of xanthine dehydrogenase and xanthine oxidase, the two forms of xanthine oxidoreductase. Contrary to previous reports, we found that the midgut gland of B. latro contains only high activities of xanthine dehydrogenase. If proteinase inhibitors were omitted from the assays, however, significant activity of xanthine oxidase was measured, a result we regard as an artifact attributable to the partial conversion of xanthine dehydrogenase to xanthine oxidase by endogenous proteinases. R cells were demonstrated to contain peroxisomes, which may be involved in lipid metabolism rather than synthesis of uric acid. J. Morphol. 241:227-235, 1999 © 1999 Wiley-Liss, Inc.

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2004-12-20T11:13:00.000-08:00

Kelie's crab wins cutest pet: christmas theme!

Christmas Theme - 'Kellie's Crab', Kellie Puddy, Rosebud, VIC

Network TEN : Welcome to the Network TEN Australia website

2004-12-20T11:10:00.000-08:00

Kerie's Crab wins Australia Cutest Pet: Christmas Theme!

Christmas Theme - 'Kellie's Crab', Kellie Puddy, Rosebud, VIC

S. Gilchrist Curriculum Vitae

2004-12-19T04:42:00.000-08:00

S. Gilchrist Curriculum Vitae: "XVII. Research Summary

In my research, I use a conceptual and quantitative approach to the interface of ecology and evolution with genetics in which hypotheses are generated and tested. Evolutionary overtones are stressed throughout the research. I would classify my research tactic as problem-oriented, thus meshing many disciplines into a unified question is necessary. Past research includes studies on populations, communities, and physiological and behavioral ecologies in aquatic and terrestrial systems. My research usually involves crustaceans, although recently I have worked with parasitic minor phyla, insects, annelids, and to a limited extent, protozoans.

Previous Projects

l. Hermit crab shell selection: This project involved a reanalysis of field and laboratory experiments used in evaluating hermit crab shell choice. A major aspect of the project was comparisons of various field crab collection techniques. A multivariate approach was used to determine what constitutes an adequate shell. Data from this project have cast doubts upon major assumptions of previous hermit crab studies.

2. Hermit crab natural history: Along with classical descriptive analyses of crab populations, I used electrophoretic techniques to examine age structure in populations. Preliminary evidence suggests that there is a high correlation between geno-phenotype and survival in at least three common hermit crabs in Alligator Harbor, Florida.

3. Parasitism and predation of hermit crabs: Little is known about the effects of parasitism on crustacean host populations in the field. I examined the relation between hermit crab predators and parasites and shell use. With data from this study, I can suggest that large shells may not necessarily be of benefit to a crab in that predators and parasites are more commonly associated with shells that are large in relation to the crab occupant. I have collected both predators and parasites of the crabs along the coast of the eastern U.S., the west coast of Florida, Honduras and on both sides of the Isthmus of Panama. Curent research involves hermit crab predation by octopuses.

4. Chemical attraction of crabs to shell sites: Simulated predation sites, areas where gastropods are eaten by crustaceans, were examined in several different habitats to determine hermit crab attraction. The number, size, and species of crabs found at the sites were highly dependent upon the area, amount, and species of the bait(gastropod) offered at the site.

5. Gastropod survey: I have compiled species lists and relative abundances of gastropods whose shells are used or could be potentially used by hermit crabs and tanaids. These lists include shells from the west coast of Florida and from both sides of the Isthmus of Panama.

6. Ecology and population genetics of reef-dwelling crustaceans: Decapod crustaceans abound on reefs, however, little work has been done to examine the role of these organisms in reef communities. Focusing on pagurids and xanthids, I am interested in studying the evolution of dependence upon coral reefs as a resource.

Current Projects

1. Chemical attraction of hermit crabs to predation sites: I am investi- gating the relative importance of chemical attraction to shell sites in habitats at Roatan Island, Honduras and in the Sarasota Bay, examining both land and marine hermit crabs.

I have access to a variety of substrates in the intertidal and reef areas of the coasts in Florida and Honduras. Additionally, I am examining differences in chemically mediated behavior in areas of different wave activities. Several students have become interested in this project, resulting in ISPs and thesis work.

2. Parasitism and predation of hermit crabs: I am currently investigating a series of questions concerning the roles that predators, both macro- and micropredators, play in shell selection behaviors of hermit crabs. In this format, I assume that parasitism is a form of predation. This project may have broad interest, including anthropological implications.

3. Gastropod survey: I am continuing to catalog shells potentially usable by hermit crabs. I am also making observations on architectural differences in shells and the relative success (abundance) of the shell form in the populations. I have over 1,000,000 shells measured, labelled, and placed into the environment around Sarasota. The 15 year study of this region constitutes one of the largest data bases of this type in the world. In Honduras, I am recording the types of molluscs found in the intertidal, back reef, and forereef areas of northern Roatan Island. I am especially interested in how hermit crabs and octopods interact.

4. Shell use and selection: Sarasota Bay offers the opportunity to look at hermit crab shell use in a shell-rich environment. I have taken series of transects in the Bay to determine shell use, shell availability, and types of predators. Focus has been recently directed to larval and juvenile crabs.

5. Genetics and learning in shell selection: I am rearing larvae of several hermit crab species (mostly pagurids) to test the hypothesis that shell selection is learned from early encounters with shells.

6. Land hermit crab studies include observations of field ecology and laboratory behaviors. As the pet industry for these animals grow, there is more pressure on field populations. Information on recruitment and resource use are vital.

7. Acoustical and chemical signalling by Aratus. I have reared these crabs and have made observations in both lab and field studies. This work meshes comparatively with studies on hermit crabs.

8. Undergraduate Research and Teaching. I have presented addresses on teaching and research techniques. Currently, I am working on analyzing active learning in the laboratory."

Dr. Ariel D - Mite Research

2004-12-19T04:11:00.000-08:00

RISE Hands-On -> Mentors -> Dr. Ariel D�az - UPR at Cayey
Dr. Ariel Díaz

* Versión en español

Research Interests

My interests are in the biology, ecology, and behavior of arthropods particularly mites (Acari). The mites are one of the most abundant and diverse arthropod groups, and are of special interest because they have evolved a multitude of ecological associations with living organisms such as fungi, plants, and animals. My students and I are currently working on three research projects involving mites. First, we are examining the interactions between the hermit crab or cobo (Coenobita clypeatus) and five mite species associated with it. While these mites have been known for decades we know little about their biology and ecology. We are researching the basic aspects of the mite’s feeding and reproductive biology, as well as their demography and geographic distribution on the island. Our second project focuses on the biology and ecology of the ectoparasitic mites associated with the house mouse, Mus musculus. The house mouse, together with it’s ectoparasites, were introduced in Puerto Rico possibly centuries ago, and are now well established on the island. We are trying to determine how local conditions affect the distribution and abundance of these mites, and how current and historical phenomena may affect the interactions between them. Finally, we are also conducting studies on the occurrence of dust mites, a source of many indoor allergens, on private student housing in Cayey, Puerto Rico. Dust mites are responsible for a large portion of the allergic asthma cases reported on the island, and our preliminary work shows that mites are very common in private student housing on this locality. We are using a combination of dust sampling and student surveys to further understand this prevailing health problem.

Students Participating In Research
Name E-Mail Project Funding
Keyla N. David Hermit crab mites AMP
María del Mar Ortega Hermit crab mites AMP
Vivian I. Soliván Hermit crab mites RISE
José Colón Mouse ectoparasites RISE
Limarys Cruz Mouse ectoparasites RISE
Eduardo A. Caussade Dust mites AMP
Josué de los Santos Dust mites RISE
Olga Rivera rivera_olga95@hotmail.com Dust Mites Graduated May 2000

Annual migrations and spawning of Coenobita clypeatus (Herbst) on Mona Island - INTERNATIONAL JOURNAL OF CRUSTACEAN RESEARCH-

2004-12-19T04:09:00.000-08:00

DADES DEL SUMARI DE CRUSTACEANA -INTERNATIONAL JOURNAL OF CRUSTACEAN RESEARCH-: "T�tol: Annual migrations and spawning of Coenobita clypeatus (Herbst) on Mona Island (Puerto Rico) and notes on inland crustaceans
Autor: Nieves-Rivera, �ngel M.; Williams Jr, Ernest H."

Behavior of Pagurus samuelis and Coenobita clypeatus during burial

2004-12-19T04:03:00.000-08:00

LLU Graduate School - Stephen G. Dunbar - hermit crabs: "Behavior of Pagurus samuelis and Coenobita clypeatus during burial; implications for the fossil record and modern ecology

Janelle ShivesJanelle Shives is a first year master's degree student. She is investigating hypotheses regarding the lack of hermit crabs found in association with gastropod shells in the fossil record. Although many gastropod shells are found throughout the fossil record with evidence that they have been 'hermitted' (Walker & Carlton, 1995), questions remain as to why so few hermit crabs are found.

Janelle's work focuses on the behaviors of Pagurus samuelis and Coenobita clypeatus in various conditions of burial stress. She is also using innovative techniques to investigate fossil gastropod shells that may hold hermit crabs that have not previously been recognized by museum curatorial staff. "

Ecological Importance of Terrestrial Hermit Crabs in the Galapagos Islands

2004-12-19T03:59:00.000-08:00

Ecological Importance of Terrestrial Hermit Crabs in the Galapagos Islands
SALLY E. WALKER (Dept. of Geology, University of Georgia, Athens, GA 30602)
Terrestrial hermit crabs are ubiquitous on tropical islands; however, their ecology is poorly known. This research was undertaken under the auspices of the Charles Darwin Research Foundation and the Galapagos National Park to determine the species of terrestrial hermit crabs that occur on the Galapagos Islands and their ecology in relation to the human population on Santa Cruz Island. The human impacted sites of Director´s Beach and Tortuga Bay and the protected site of Puerto Nuñez were used in this study. Coenobita compressus was the only species encountered. Thais melones was the most commonly used shell at Director’s Beach (54%) while Nerita scabricosta was used by 65% of the hermits at Tortuga Bay and by 75% at Puerto Nuñez. At the human-affected sites, C. compressus emerged 1 to 1.5 hours after sunset to forage on bananas, corn cobs, bread, and grapefruit which were discarded by tourists. Crabs were afraid of humans at these localities, stopping behavior upon approach. At the protected site, crabs appeared two hours before sunset and were not afraid of humans — continuing with mating, aggressive behavior and food foraging. They consumed the purple flowers of Sesuvium, leaves of Tiquilia galapagoa, and foraged within driftwood and mangrove litter. However, the crabs were attracted to the camp garbage and ate the plastic garbage bag, paper labels off the cans, and "papeles de higenico". In summary, these "Cangrejos de Basura" are indeed important organisms for maintaining the cleanliness of Galapagos beaches with their late night beach-sweeping activities.

Citation:

Walker, S.E. 1999. Ecological importance of terrestrial hermit crabs in the Galapagos Islands. Proceedings of the American Association for the Advancement of Science, Pacific Division 18 (1): 86.

Mites on Coenobita clypeatus

2004-12-19T03:56:00.000-08:00

acarology discussion list 9906: "From: 'Jose G. Palacios Vargas'
To: AGCAN.INTERNET('acarology@nhm.ac.uk')
Date: 6/5/98 6:37pm
Subject: Ewingiidae

Dear acarologist,

I would appreciate very much to know the references about the Astigmata mites of the family Ewingiidae. We have found some specimens on the hermit crab Coenobita from Quitana Roo Cost (close to Can Cun) Mexico.

Thank you very much Dr. Jose Palacios

From: 'Barry M. OConnor'
To: 'Jose G. Palacios Vargas' Date: 6/7/98 3:24pm
Subject: Re: Ewingiidae

At 5:37 PM -0500 6/5/98, Jose G. Palacios Vargas wrote:
>Dear acarologist,
>
> I would appreciate very much to know the references about the Astigmata mites of the family
>Ewingiidae. We have found some specimens on the hermit crab Coenobita from Quitana Roo Cost >(close to Can Cun) Mexico.
>
>Dear Jos� - Your host crab is most likely Coenobita clypeatus, the only Coenobita known from the
>western Atlantic coasts from Florida to Venezuela. This crab is host to Ewingia coenobita Pearse,
>1929, which occurs on the gills, and Askinasia antillarum Fain, Yunker, van Goethem & Johnston,
>1982 which occurs on the setae near the posterior lateral edge of the carapace.
Modern descriptions of these species can be found in the following papers:

Yunker, C.E. 1970. New genera and species of Ewingidae (Acari:Sarcoptiformes) from Pagurids (Crustacea) with notes on Ewingia coenobitae Pearse, 1929. Rev. Zool. Bot. Afr. 81: 237-254.

Fain, A., C.E. Yunker, J. van Goethem & D.E. Johnston. 1982. Notes on the Ewingiidae (Acari, Astigmata) living in association with pagurids and fresh-water crabs (Crustacea) with description of a new genus and a new species. Bull. Inst. r. Sci. Nat. Belg. Entomol. 54(8): 1-7.

In 1982 I placed the 'Ewingiidae' as a subgroup in the family Acaridae. As part of my current research on t"

Bulletin of Zoological Nomenclature 59(1) March 2002

2004-12-19T03:52:00.000-08:00

Bulletin of Zoological Nomenclature 59(1) March 2002: "Pagurus clypeatus Fabricius, 1787 (currently Coenobita clypeatus; Crustacea, Decapoda): proposed replacement of syntypes by a neotype

Patsy A. McLaughlin
Shannon Point Marine Center, Western Washington University, 1900 Shannon Point Road, Anacortes, WA 98221-9081B, U.S.A.

Lipke B. Holthuis
Nationaal Natuurhistorisch Museum, Naturalis, P.O. Box 9517, 2300 RA Leiden, The Netherlands

Abstract. The purpose of this application is to conserve the accustomed usage of the name of the common West Indian land hermit crab Coenobita clypeatus (Fabricius, 1787), the type species of Coenobita Latreille, 1829. The two existing syntypes represent two different and equally well known Indo-Pacific species: Coenobita rugosus Milne Edwards, 1837 and C. violascens Heller, 1862. It is proposed that stability should be maintained by the replacement of the two existing East Indies syntypes of Pagurus clypeatus Fabricius, 1787 with a West Indies neotype in the sense of the usage of the name since 1919. This will also conserve the names C. rugosus and C. violascens. The names of Coenobita Latreille, 1829 and of its type species, Pagurus clypeatus Fabricius, 1787, were placed on Official Lists in Opinion 1575 (March 1990).

Keywords. Nomenclature; taxonomy; Crustacea; Decapoda; COENOBITIDAE; Coenobita; Coenobita clypeatus; C. rugosus; C. violascens; hermit crabs; West Indies."

Cute flash animation featuring hermit crabs

2004-12-19T01:36:00.000-08:00

Cute flash animation about refining your research topic. Tommy researches the effects of pollution on hermit crabs.

Dietary assimilation and the digestive strategy of the omnivorous anomuran land crab Birgus latro (Coenobitidae)

2004-12-19T01:04:00.000-08:00

Dietary assimilation and the digestive strategy of the omnivorous anomuran land crab Birgus latro (Coenobitidae)

Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology
Publisher: Springer-Verlag Heidelberg
ISSN: 0174-1578 (Paper) 1432-136X (Online)
DOI: 10.1007/s00360-004-0415-7
Issue: Volume 174, Number 4
Date: May 2004
Pages: 299 - 308
Original Paper
Dietary assimilation and the digestive strategy of the omnivorous anomuran land crab Birgus latro (Coenobitidae)

Joanne E. Wilde1, Stuart M. Linton1 and Peter Greenaway1 Contact Information
(1) School of Biological, Earth and Environmental Sciences, The University of NSW, 2052 Sydney, NSW, Australia

Accepted: 15 January 2004 Published online: 4 February 2004
Abstract On Christmas Island, Indian Ocean, the diet of robber crabs, Birgus latro (Linnaeus) was generally high in fat, storage polysaccharides or protein and largely comprised fruits, seeds, nuts and animal material. The plant items also contained significant amounts of hemicellulose and cellulose. In laboratory feeding trials, crabs had similar intakes of dry matter when fed artificial diets high in either fat or storage polysaccharide, but intake was lower on a high protein diet. Assimilation coefficients of dry matter (69–74%), carbon (72–81%), nitrogen (76–100%), lipid (71–96%) and storage polysaccharide (89–99%) were high on all three diets. B. latro also assimilated significant amounts of the chitin ingested in the high protein diet ( 93%) and hemicellulose (49.6–65%) and cellulose (16–53%) from the high carbohydrate and high fat diets. This is consistent with the presence of chitinase, hemicellulase and cellulase enzymes in the digestive tract of B. latro. The mean retention time (27.2 h) for a dietary particle marker (57Co-labelled microspheres) was longer than measured in leaf-eating land crabs. The feeding strategy of B. latro involves the selection of highly digestible and nutrient-rich plant and animal material and retention of the digesta for a period long enough to allow extensive exploitation of storage carbohydrates, lipids, protein and significant amounts of structural carbohydrates (hemicellulose, cellulose and chitin).

Keywords Birgus latro - Land crab - Digestion - Diet - Robber crab - Dietary assimilation.

2004-12-18T09:27:00.000-08:00

Welcome to the Hermit Crab Wiki. A "Wiki" is an encyclopedia that can be edited by any web user. http://www.hermitcrabaddiction.com/wiki/

2004-11-09T05:03:00.000-08:00

Christmas Island is also part of the network of habitats protecting migratory species under the JAMBA and CAMBA agreements. The Hosnie's Spring area on the east coast of the island has been designated as a Wetland of International Importance under the Ramsar Convention on Wetlands. This site is remarkable because it contains a small stand of Bruguiera mangroves growing in freshwater 37 m above sea level. The stand has probably persisted in this location for up to 120,000 years. The Dales area, on the west coast, is currently under consideration for the same listing.

Robber Crab
Rainforest on Christmas Island is considered unique because many of it's key ecological processes, such as seed dispersal and predation, seedling regeneration and nutrient cycling, are almost entirely regulated by a single species, the red land crab (Gecarcoidea natalis). More than 40 million red crabs live in burrows throughout rainforest on the island, and their dominance in structuring the entire ecosystem is of outstanding scientific interest. These crabs are famed for their annual breeding migrations to the sea. The massed migration of millions of red crabs across the island at the end of each year is one of the great spectacles of the natural world.

The south coast of the the island
The diversity and abundance of crabs on Christmas Island is of great conservation significance. Twenty-three land and shoreline crabs are native to the island, including the robber (or coconut) crab, Birgus latro. Elsewhere in its range, populations of this species have been severely depleted by hunting and habitat clearance. The robber crab population on Christmas Island is recognised as the largest and most intact anywhere in the world. Perhaps one of Christmas Island's greatest assets is that it is still relatively intact; about 75% of Christmas Island's 135 square kilometres is still cloaked by undisturbed, primary forest. Although the island has lost several endemic species since it was first settled in 1888, and invasive species are cause for concern, the island's biota is, by world standards, in remarkably good shape. World Heritage Listing

Red Crabs
The best way to sum up the significance of Christmas Island's natural heritage is to consider it in the context of World Heritage. A site can be inscribed on the World Heritage list if it fulfils just one of the following; it represents a major stage of the earth's history, it is an outstanding example of ongoing ecological and biological processes, it contains superlative natural phenomena or areas of natural beauty, or it contains the most important natural habitats for the conservation of biological diversity. Expert advice indicates that Christmas Island would qualify as a World Heritage site on three of these four categories. The Issues Several developments threaten the integrity of the environment on Christmas Island Phosphate Mining Land "Swaps" Asia Pacific Space Centre Detention Centre Yellow Crazy Ants For more information, please contact: Pete Green Christmas Island Campaigner Email Pete Green Created: 19 Aug 2002 | Last updated: 19 Aug 2002 Print this page Email to a friend

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2004-11-06T02:46:00.000-08:00

Crustaceana
76 (5): 547-558, May 1 2003
Copyright © 2003 Koninklijke Brill, Leiden 2003
All rights reserved
Annual migrations and spawning of Coenobita clypeatus (Herbst) on Mona Island (Puerto Rico) and notes on inland crustaceans
Ángel M. Nieves-Rivera
Ernest H. Williams
Abstract
Annual migrations and spawning for the common land hermit crab, Coenobita clypeatus in Playa Sardinera and possibly in Uvero, Mona Island, occur in August or early September. Spawning corresponds to the crescent moon in the lunar cycle.

2004-10-29T05:38:00.000-07:00

Naturalistic vivariums which feature large pieces of driftwood and plants

2004-10-29T05:37:00.000-07:00

NATURESCAPE POOLS Natural looking, high-grade resin pools for the terrarium.
http://www.peregrine-livefoods.co.uk/Pools.htm

2004-10-29T05:36:00.000-07:00

Misting Systems

2004-10-29T05:19:00.000-07:00

132 GILCHRIST, S.L.* and J. Hermit crab shell cycling between seagrass, HICKMOTT. New College of USF, backreef, and reef habitats at Bailey's Cay, Roatan, Sarasota, FL. Honduras.

2004-10-29T04:26:00.000-07:00

Photo of Glogg, a land hermit crab owned by Marie (marie@netforces.org) recently moulting. On surfacing, his owner noticed a black spot on the right cheliped.

2004-10-26T11:06:00.000-07:00

August 24, 2004

Shell game
Whoa! I just realized that I almost forgot to post any pictures from my trip.
Here's one which expresses my mood perfectly:

Frankly, looking at that picture makes me jealous!
These little critters don't have to worry about elections; they can just tuck themselves into their shells. Well, maybe not "their" shells in the strictest sense, but when the original owner dies or gets eaten, why let a perfectly good shell go to waste? So what if it's pre-owned? And once you outgrow the shell, you just find another one, and leave the last one behind for some other deserving hermit. They get pretty big too; while I was SCUBA diving I saw one inside a large conch shell. (Well meaning humans even make designer shells for their captives.)
The guys in the above picture are Caribbean Land Crabs -- Coenobita clypeatus. They have gills, but use them as lungs by means of a curious adaptation:
As an adaptation for extracting oxygen from the air rather than from the water, the gills of Coenobita are reduced in number and stiffened, and the inner walls of the gill chamber are vascularized to promote the exchange of gases. Also, ventilation of the gill chamber is enhanced by the reduced side walls of the carapace or head shield of the crab. Moistening of the gills is abetted by well-developed glands in the bronchial region.
Gills as lungs? It may sound unnatural to some, but they've been doing it so long that in captivity they can be terrified of water . Yup; well-meaning owners can kill them by just by giving them a bath.
That's because their shells hold water in just the right balance for the crabs:
The danger of drying out or of over concentrating the body fluids through evaporation is the most critical problem confronting any animal that migrates from water to land. Coenobita has an advantage in this respect over the true land crabs, for it can store water in the appropriated snail shell, and this water may be used secondarily for drinking. One reason that hermit crabs so frequently try on different abandoned snail shells is to find one that fits the delicate abdomen closely, thereby minimizing evaporation. The same explanation probably accounts for the nocturnal habits of Coenobita Clypeatus in the southern part of its range, where daytime activity could result in severe evaporation. Experiments have shown that animals in well-fitting shells can subsist without food and water six times as long as those removed from their shells. When the crab withdraws into its shell in the daytime, the claws and walking legs form a reasonably effective seal in the shell mouth against evaporation. The parts of the animal that protrude farthest from the snail shell are most heavily calcified, and this undoubtedly helps to prevent the evaporation of body fluids.
Coenobita takes up water by dipping the tips of the claws in it, transferring drops to the mouthparts or maxillipeds and thence to the mouth and gill chamber. Very small amounts of water, such as raindrops and dew, can be utilized in this way. An alternate method is to hold both claws close together and dip them in the water; by shoveling motions, the water is forced to rise by capillary action along the fringe of hairs on the lower surfaces of the claws, and the maxillipeds, direct it to the mouth. Coenobita has a highly developed sensory perception for water; it prefers water of low salinity and it is able to discriminate well between different salinities. The animals seem to remain in best condition when a small amount of salt is present in the drinking water. Full-strength sea water can be used for drinking, but not for shell water-, the latter must be constantly diluted with nearly fresh water to prevent adverse concentration of the body fluids.
While that's more than I really needed to know, I can't say I disagree with any of it. I'm all in favor of preventing adverse concentration of body fluids, although I have nothing against trying on new shells.
NOTE: I don't mean to offend any crabs or hermits who might be reading this post. I'm a crab myself as well as a borderline hermit.

posted by Eric on 08.24.04 at 05:04 PM

2004-10-26T09:27:00.000-07:00

1(ii) HORIZONTAL ZONATION of the associated animals in the mangal
The main differences are due to the 'wetness' (SE Asia is very wet) and substratum type (sand/mud). Crabs dominate in all zones, they dominate in numbers and importance to the ecosystem. There are about 60 genera of crabs within the mangrove ecosystems. Fiddler crabs (Ocyponidae) such as Uca spp. live on the mud flats, Cardisoma (in the New World replaced by Ucides) are at the high shore. There are lots of Grapsid crabs (which in the New World are replaced by Aratus and Goniopsis).
Zonation in the Indo-Pacific
Landward fringe - From high water to ordinary spring tide level upwards there are a number of crabs and hermit crabs which are generally secretive in habitat. There are usually a large population of Uca spp. Examples of typical species: Coenobita (a hermit crab), Cardisoma (a burrowing land crab) - this is found in sand, Thallassina sp. (the Mud Lobster) - found in more mud/clayey substrate, Uca lactea, Sesarmid crabs (which use the Mud Lobster burrow). In the New World (Neotropics) there is a different species of Cardisoma (C.guanhumi) and crabs of the genus Ucides.

2004-10-26T09:09:00.000-07:00

Coenobita compressus. If we move to the upper beach, roadway and airstrip areas, the more common resident is the "hermit crab". Hermit crabs have a large, uncalcified abdomen that is normally kept concealed within an empty gastropod shell. Their distribution is traceable to water availability. They usually seem to require access to standing water for drinking and to replenish the reserve carried in the shell, although at least some species can extract water from damp sand by an unknown mechanism. A well-fitting shell is essential for maintaining low evaporation rates and carrying ample water. An appropriately sized shell in good condition allows invasion of inland environments offering more shade, food and fresh water.
Hermit crabs, with their heavy adopted shells, are the most cumbersome of land crabs. They feed on various forms of vegetation and destritus and the feces of horses and cows. They are also very effective carrion scavengers.
Reproduction in coenobitids has received little attention. Hermit crabs apparently go to the shore prior to mating, although copulation has gone largley unobserved. The eggs are hatched and the larvae shed into the sea where they undergo normal plaktonic development. They then move inland, where they lead a mainly nocturnal existence, by day sheltering in cracks under ledges or logs, or buried in the sand -although they may be active by day (as is the case here) in humid conditions or in rain.

2004-10-26T09:07:00.000-07:00

NOTEWORTHY FAUNA Ducie Atoll is particularly important for its large breeding populations of sea-birds. The island supports probably the world's largest breeding colony of Murphy's Petrels (Pterodroma ultima), with around 250,000 pairs, as well as about 20,000 pairs of Kermadec Petrels (P. neglecta) and 20,000 pairs of Herald Petrels (P. heraldica). Other breeding seabirds include Christmas Shearwater (Puffinus nativitatis), Red-tailed Tropicbird (Phaethon rubricauda), boobies (Sula spp.), Great Frigatebird (Fregata minor), Sooty Tern (Sterna fuscata), Brown Noddy (Anous stolidus), Blue-grey Noddy (Procelsterna cerulea) and Fairy Tern (Gygis alba). Three species of migrant shorebirds have been reported, Wandering Tattler (Heteroscelus incanus), Bristle-thighed Curlew (Numenius tahitiensis) and Sanderling (Calidris alba), but numbers are generally low (less than 20). There are no land-birds, and the only mammal present is the Polynesian Rat (Rattus exulans). Two species of land hermit crab (Coenobita spp.) have been recorded. The fish fauna is considered to be impoverished; only 138 species were recorded by Rehder and Randall (1975), with 15 of these being confined to southeastern Oceania. However, the island has a reputation for its large shark population. Insects, crustaceans, echinoderms and corals are listed by Rehder and Randall (1975).
NOTEWORTHY FLORA The island is exceptional for the paucity of its flora; only two species of vascular plants are known.
SCIENTIFIC RESEARCH AND FACILITIES The island was visited by the Whitney South Sea Expedition in 1922, by the 1970-71 National Geographic Society-Oceanic Institute Expedition to Southeast Oceania, and by Operation Raleigh in 1987. Scientists from the Pitcairn Islands Scientific Expedition (based on Henderson) visited the island at approximately three-monthly intervals during 1991.
RECREATION AND TOURISM The island has some value for "high-quality" tourism, e.g. for passengers from Society Expeditions cruise ships.
MANAGEMENT AUTHORITY AND JURISDICTION Pitcairn Islands Council in conjunction with the British Consulate-General in Auckland (New Zealand).
REFERENCES Dahl (1980, 1986); Elliot (1973); Hepburn et al. (1992); Rehder & Randall (1975); UNEP/IUCN (1988).
REASONS FOR INCLUSION 1a, 2a, 2c. An exceptionally undisturbed atoll ecosystem and one that, by virtue of its geographical location, is likely to remain so.
SOURCE M. de L. Brooke and references.

For help with this web site contact: Protected Areas Programme UNEP World Conservation Monitoring Centre 219 Huntingdon Road Cambridge CB3 0DL United Kingdom Information Enquiries Tel: +44 (0)1223 277722 Main Switchboard Tel: +44 (0)1223 277314 Fax: +44 (0)1223 277136 Email: info@unep-wcmc.org

2004-10-26T09:03:00.000-07:00

Morris, S. and Bridges, C.R. (1986) An in vitro investigation of the modulation of haemocyanin oxygen affinity in the land hermit crab Coenobita clypaetus Herbst. Physiol. Zool., 59, 606 - 615. Morris, S., Bridges, C.R. and Grieshaber, M.K. (1987) Regulation of haemocyanin oxygen affinity during emersion of the crayfish Austropotamobius pallipes. III. The dependence of Ca2+ binding on the concentration of L-lactate. J. Exp. Biol., 33, 339 - 352. Atkinson, R.J.A., Pelster, B., Bridges, C.R., Taylor A.C. and Morris, S. (1987) Behaviourial and physiological adaptations to a burrowing lifestyle in the snake blenny, Lumpenus lampretaeformis and the red band-fish, Cepola rubescens. J. Fish Biol., 31, 639 - 659. Morris, S., Greenaway, P. and McMahon, B.R. (1988) Oxygen and carbon dioxide transport by the haemocyanin of an amphibious crab; Holthuisana transversa. J. Comp. Physiol. 157, 873 - 882. Morris, S., Taylor, A.C. and Bridges, C.R. (1988) The effect of simultaneous salinity and oxygen stress on haemocyanin function in Palaemon elegans: The role of acclimation. Comp. Biochem. Physiol. 90A, 31 - 39. Morris, S. (1988) Effects of freezing on the function and association state of crustacean haemocyanins. J. Exp. Biol. 138, 535 - 539. Morris, S. and Taylor, A.C. (1988). L-lactate effects carbon dioxide transport by crustacean haemolymph. Comp. Biochem. Physiol. 91A, 523 - 527. Morris, S., Greenaway, P. and McMahon, B.R. (1988). Adaptations to a terrestrial existence in the Robber Crab Birgus latro L. I. An in vitro investigation of blood gas transport. J. Exp. Biol. 140, 477 - 491. Greenaway, P., Morris, S. and McMahon, B.R. (1988). Adaptations to a terrestrial existence in the Robber Crab Birgus latro L. II. In vivo respiratory gas exchange and transport. J. Exp. Biol. 140, 493 - 509.

2004-10-26T09:02:00.000-07:00

Coenobita perlatus
(land hermit crab)
Information
Classification
2004/10/23 06:31:27.534 GMT-4
By Noelle M. McKenzie
Kingdom: Animalia
Phylum: Arthropoda
Class: Malacostraca
Order: Decapoda
Suborder: Pleocyemata
Family: Coenobitidae
Genus: Coenobita
Species: Coenobita perlatus
Geographic Range
Coenobita perlatus is found in the Indo-Pacific from the Islands of Aldabra, Mauritius, and Seychelles through Samoa. These areas are located in the south central Pacific Ocean about 1,600 miles northeast of New Zealand, north of Madagascar and directly above the 10 degree latitude line. (Ingle, 1993)
Biogeographic Regions: ethiopian (native ); australian (native ); oceanic islands (native ); indian ocean (native ); pacific ocean (native ).
Habitat
Coenobita perlatus are found living near coastal shorelines. Coenobita perlatus require regular access to the sea or water of high salinity. They are never far from shore or adjacent dunes, and have been found in tidal pools, sandy areas, and humid areas with dune vegetation. Migration occurs from the dune areas to the sea when C. perlatus need to release their eggs into the water or are in need of water to maintain their body moisture. (Hazlett, 1998, Burggren, 1988, Veltman, 1997)
These animals are found in the following types of habitat: tropical ; terrestrial ; saltwater or marine .
Terrestrial Biomes: desert or dune ; forest ; scrub forest .
Aquatic Biomes: coastal .
Other: intertidal or littoral .
Physical Description
Mass
80 g (average)
(2.82 oz)

Length
800 mm (average)
(31.5 in)

Coenobita perlatus are approximately 80mm long and 80g in body mass. They occupy the multicolored discarded shells of gastropods in order to protect their soft, coiled abdomen and inner organs such as the liver and gonads. These land hermit crabs are decapods, which means they have 10 legs (5 pairs): The first pair is modified as the claws or chelipeds (pinchers), and two pairs of legs are used for walking. The next pair, the claws, are used for defense and transporting food and water to the their mouth. The last two pairs are highly modified but are used more for cleaning than holding on to the shell. When walking, these crabs drag their shells along, but despite this burden, they can run quickly. Each C. perlatus has a loosely fitting carapace that covers the forepart of the body. Coenobita perlatus prefer shells that fit snugly in order to prevent evaporation of moisture and to protect their soft abdomens. Coenobita perlatus have four antennae that help them to sense their surroundings. They have shown some geographic physical variation, but this variations have not been studied in depth.
Male and female C. perlatus can only be distinguished when they are out of their shells. Both the female and male genital pores are located on the coxal ventral surface of each pereiopod (on an appendage of one of the first five abdominal segments), and a long coxal tube (an extension of a pereiopod which is joined broadly to lateral margins of tergites) is present in the male.
(Hazlett, 1998, Burggren, 1988, Veltman, 1997)
Some key physical features: ectothermic ; heterothermic ; bilateral symmetry .
Sexual dimorphism: sexes shaped differently.
Reproduction
These creatures reproduce sexually and will not reproduce in captivity. Reproduction occurs while both individuals are in intermolt (hard-shelled stage), often in or near the burrows of males, or on land near the sea. Male C. perlatus place a spermatophore on the female (externally) which is then dissolved by secretions as the eggs are released. The eggs (about 10,000-50,000 per fertilization) are attached to the pleopods (appendages used for swimming) on the female's abdomen and remain there for some time. Female C. perlatus moisten the eggs with water that is held in the gastropod shell. After the eggs develop, females carry them on their abdomens to the sea, where they leave them on wet sand or a wet rock for the tide to carry them out to sea. The eggs are hatched and the larvae undergo planktonic development. Young C. perlatus are small, molting several times while still at sea in order to reach adult size. They then move to land, where they are vulnerable to their predators until they find a shell. Once C. perlatus have found shells, they live on land the rest of their lives. (Hazlett, 1998, Burggren, 1988, Ingle, 1993, Veltman, 1997)
Lifespan/Longevity
Longest known lifespan in wild
25-30 years (high)

Expected lifespan in captivity
1-4 years (average)

Coenobita perlatus can live up to 25-30 years in the wild, but once in captivity they typically live from 1-4 years.
Behavior
Despite the common name hermit crab, which alludes to a solitary lifestyle, these are very social creatures. They travel in groups of about 25 and are found, in the wild, living in colonies of up to 100 or more. Coenobita perlatus are nocturnal. During the day, when it is hot, they bury themselves in the damp sand or take shelter under ledges of logs to keep cool and reduce moisture loss. Afternoon tropical sun is a danger to these crabs because they require a certain amount of moisture for their gills to operate properly. If they become too dry, they can suffocate. In addition to taking cover from the sun, they also have gills on their big claw in order to conserve moisture. These gills must be kept wet to maintain good health.
When C. perlatus no longer fit their shells they look for bigger ones. The original occupant of the shell, if still present, is quickly removed, and the aggressor moves into its new home. If frightened, land hermit crabs may grasp things tightly with their claws. Even the smallest C. perlatus can draw blood if scared. (Hazlett 1988, Ingle 1993)
Key behaviors: terricolous; nocturnal ; motile ; sedentary ; social .
Communication and Perception
Coenobita perlatus have been observed communicating to one another by making sounds referred to as chirping. They use their antennae to sense smells and have excellent vision. They are also sensitive to vibrations.
Communicates with: visual ; tactile ; acoustic ; chemical .
Perception channels: visual ; tactile ; acoustic ; vibrations ; chemical .
Food Habits
Known as "garbage collectors of the seashore," Coenobita perlatus individuals are scavengers, eating a variety of dead and rotting material found along the seashore. These crabs, in general, do not fight over food and can often go long periods of time without food or water. Most C. perlatus carry water in their shells, which the use for breathing and as a water source when they are far from the sea. (Ingle, 1993)
Primary Diet: carnivore (scavenger ); detritivore .
Animal Foods: carrion .
Other Foods: detritus .
Economic Importance for Humans: Negative
Economic Importance for Humans: Positive
Coenobita perlatus can be used as a source of food for humans, but are most commonly found as household pets. They also play a vital role in seashore clean-up because they are scavengers. By ridding the shoreline of dead sea matter and other material that collects on the shore, hermit crabs are beneficial in keeping the shoreline clean and creating a healthier environment for humans and other aquatic and coastal organisms. (Veltman, 1997)
Ways that people benefit from these animals: pet trade ; food .
Conservation Status
Humans are currently the greatest danger to Coenobita perlatus. Though these creatures are not going extinct and are not yet endangered, we humans are destroying their habitats, collecting the crabs for food, over- collecting for pet shops, and polluting the environment. There are many conservation actions currently taking place that affect C. perlatus indirectly. These include shoreline clean-up of human pollution, and prevention of pollution by factories and barges. Pollution is a great threat to C. perlatus because they need a healthy environment to reproduce properly, a safe place to grow their eggs, and clean land and water to live on and drink from.
Other Comments
Growth on land is accomplished by the shedding of their exoskeleton. It takes about ten days for their skin to harden after molting, and as they grow larger, they search out roomier shells to more comfortably accommodate thier bodies. (Hazlett, 1998, Veltman, 1997)
Contributors
Noelle M. McKenzie (author), University of Michigan: June, 1999.
References

Dr. Brian Hazlett, Professor of Biology Department, University of Michigan

Burggren, W. and McMahon, B. 1988. Biology of the Land Crabs. Cambridge University Press, Cambridge.

Ingle, R.1993. Hermit Crabs of the Northeastern Atlantic Ocean and the Mediterranean Sea. Chapman & Hall: Natural History Museum Publications, London.

Lloyd Center Research Program. 1996. http://www.ultranet.com/~lloydctr/hermit.html

http://www.pathfinder.com/PetPath/Exotic/Breeds/AQUATIC/HERMITC/HERMITC.html

http://dino.slsa.sa.gov.au/sagov/agencies/museum/hermit.htm

Veltman, T. 1997. http://www.xs4all.nl/~pal/hermit.htm

2004/10/23 06:31:29.058 GMT-4
To cite this page: McKenzie, N. 1999. "Coenobita perlatus" (On-line), Animal Diversity Web. Accessed October 26, 2004 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Coenobita_perlatus.html.

2004-10-24T09:34:00.000-07:00

Information about Coenobita including descriotion of the eyestalks as "laterally flattened; eyes held subparallel to each other"

2004-10-24T09:32:00.000-07:00

Coenobitidae in 'Zoological Catalogue of Australia Crustacea: Malacostraca Zoological Catalogue of Australia.

2004-10-24T09:22:00.000-07:00

Russian site which presents two photos of hermit crabs labelled Coenobita variabilis that are perhaps misidentified

2004-10-24T09:21:00.001-07:00

Close up of hermit crab perhaps wrongly identified as C. variabilis

2004-10-24T09:21:00.000-07:00

Photo of crabitat with what has been labelled as C. variabilis, perhaps mistakenly. Looks more like C. purpureus

2004-10-07T16:24:00.000-07:00

edible plants, by tremolo

2004-10-07T16:20:00.001-07:00

Wonderful photos of C. purpureus and C. cavipes

2004-10-07T16:20:00.000-07:00