Shell Selection and Utilization by the Terrestrial Hermit Crab Coenobita Rugosus in Natural and Laboratory Conditions (original) (raw)
Related papers
Journal of Experimental Marine Biology and Ecology, 2009
Experimental analyses of hermit crabs and their preferences for shells are essential to understand the intrinsic relationship of the crabs' dependence on shells, and may be useful to explain their shell use pattern in nature. The aim of this study was to evaluate the effect of crab species and site on the pattern of shell use, selection, and preference in the south-western Atlantic hermit crabs Pagurus brevidactylus and Pagurus criniticornis, comparing sympatric and allopatric populations. Differently from the traditional approach to evaluate shell preference by simply determining the shell selection pattern (i.e., the number of shells of each type selected), preference was defined (according to [Liszka, D., Underwood, A.J., 1990. An experimental design to determine preferences for gastropod shells by a hermit-crab. J. Exp. Mar. Biol. Ecol., 137(1), 47–62]) by the comparison of the number of crabs changing for a particular shell type when three options were given (Cerithium atratum, Morula nodulosa, and Tegula viridula) with the number of crabs changing for this same type when only this type was offered. The effect of crab species was tested at Cabelo Gordo Beach, where P. brevidactylus was found occupying shells of C. atratum, M. nodulosa, and T. viridula in similar frequencies, whereas P. criniticornis occupied predominantly shells of C. atratum. In laboratory experiments the selection patterns of the two hermit-crab species for these three gastropods were different, with P. criniticornis selecting mainly shells of C. atratum, and P. brevidactylus selecting more shells of M. nodulosa. The shell preference was also dependent on crab species, with P. criniticornis showing a clear preference for shells of C. atratum, whereas P. brevidactylus did not show a preference for any of the tested shells. The effect of site was tested for the two species comparing data from Cabelo Gordo to Preta (P. brevidactylus) and Araçá beaches (P. criniticornis). The pattern of shell use, selection, and preference was demonstrated to be dependent on site only for P. brevidactylus. The results also showed that the shell use pattern of P. criniticornis can be explained by its preference at both sites, whereas for P. brevidactylus it occurred only at Cabelo Gordo, where the absence of preference was correlated with the similar use of the three gastropod species studied. Finally, the results showed that the shell selection pattern cannot be considered as a measure of shell preference, since it overestimates crab selectivity.
Marine and Freshwater Behaviour and Physiology, 2009
and-conditions-of-access.pdf This article may be used for research, teaching and private study purposes. Any substantial or systematic reproduction, redistribution , reselling , loan or sub-licensing, systematic supply or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material.
Journal of Zoology, 2005
Terrestrial hermit crabs use mollusc shells to protect their soft bodies from predation and desiccation, but their use is costly. The energetic short-term cost of using shells has been demonstrated, yet this could theoretically be overcome by increasing feeding rate or food quality. In the long term, shells have the potential to constrain growth, which may in turn have a negative effect on fitness. Thus crabs should choose the lightest (least expensive to carry) shell amongst those of a size that permit growth. Since in nature lighter shells are also thinner-walled, these may provide insufficient protection from predation or desiccation, facing the crabs with a trade-off between protection and growth. This potential trade-off was investigated in the terrestrial hermit crab Coenobita compressus. Crabs were individually maintained in captivity for a variable period of between 1 and 7 months, during which light or heavy replicates of the preferred shell were available. In a second experiment, crabs were given a choice between a thick (and heavy) or a thin (and light) shell. In addition, the resistance and water retention capacity of thin and thick shells was compared. As predicted, crab growth was negatively correlated with the weight of the shell used, but crabs rejected the thin (light) shells. Thin shells were more likely to break when crabs used the normal 'rolling' behaviour in response to perceived threats. In addition, thin shells lost water at a faster rate than thick ones. Since two putative functions of shell use in terrestrial hermit crabs are protection against predation and against desiccation, it is inferred that the preference for shells of intermediate weight in C. compressus results from a balance between the need to grow and the cost of carrying a brittle shell that is not sufficiently water tight.
Shell choice and occupation by the hermit crab (Crustacea: Diogenidae) in laboratory environment
International Journal of Aquatic Biology, 2018
The Neotropical hermit crabs’ behaviour is rarely studied, although it is an important tool for the conservation of these invertebrates. In this context, the present study aimed to describe the hermit crab ethogram on its behaviour in the choice and dispute by shells. 60 specimens of hermit crabs were collected that were occupying mollusc shells Cerithium atratum , in sandstone reefs. In the laboratory, 30 hermit crabs were removed from their host shells by heating, the rest remained in their shells. The specimens were submitted to five experimental tests: (I) behaviour, (II) shell dispute, (III) shell preference, (IV) specimen behaviour with and without shell, and (V) shell contention between individuals with and without shell. The ethogram was built and evaluated by the Ad Libitum type of observational sampling methods and by the scanning type, for 30 uninterrupted minutes, records every two minutes, in total 15 observations per each observer. There were eight behavioural acts div...
Journal of Experimental Marine Biology and Ecology, 2015
Hermit crabs are notoriously choosy about the gastropod shells they live in. Many periwinkle shells at Nahant, Massachusetts, U.S.A. contain the gastropod Crepidula plana, which forms a thin flat shell inside the periwinkle shell. This study examined how the presence of C. plana affected shell selection behavior by the hermit crab Pagurus longicarpus: naked hermit crabs were offered different combinations of shells, including some containing C. plana and some that had been drilled by naticid gastropods, and their choices were recorded. Because we had to evict hermit crabs from their shells before conducting our choice tests, we also determined rates of recovery from five commonly used shell eviction techniques. No hermit crabs were successfully evicted using low salinity seawater. For the other techniques used, hermit crabs took significantly longer to recover after being removed by gentle but continuous pulling on the carapace and appendages than after being removed by immersion in heated seawater, cracking the shell using a vise, or prodding the hermit crab in the abdomen through a hole drilled in the shell. Even so, most hermit crabs recovered from all of the stresses tested within 20 h, and from at least some stresses within 2-6 h. If shells are to be re-used for experiments, heating seawater is the best technique for evicting P. longicarpus; otherwise, cracking the shell using a vise is recommended. When provided with intact shells and similarly-sized shells containing adult C. plana, all of the hermit crabs chose shells without C. plana, and did so within only about 30 min. However, given a choice between shells housing C. plana and those bearing drill holes-shells which they normally avoid-the hermit crabs were about evenly divided in their choice of shells, and many of the hermit crabs never made a final decision even after 18 or 19 h, suggesting that the presence of C. plana greatly reduces shell attractiveness and suitability. The presence of C. plana increased total shell weight and reduced internal shell volume considerably, and also weakened the shell substantially, likely making the hermit crabs more vulnerable to predators; all of these factors may play a role in selecting for the intense avoidance behavior exhibited by this species for periwinkle shells bearing C. plana.
Shell recruitment in the Mediterranean hermit crab< i> Clibanarius erythropus
2009
Gastropod shells are vital for the majority of hermit crab species, being essential for their survival, growth, protection, and reproduction. Given their importance, shells are acquired and transferred between crabs through several modalities. We conducted observations and experiments at the Asinara Island (Sardinia, Italy) to investigate the efficacy of the different behavioral tactics adopted by the hermit crab Clibanarius erythropus to acquire shells, such as: (1) locomotion and activity at different tidal phases; (2) attendance at shell-supplying sites (simulated predation sites with five different odors: live and dead gastropods, live and dead crabs, predator); and (3) interactions with conspecifics in aggregations on simulated gastropod predation sites. In each tidal phase, locomotion was slow (0.7 cm min − 1) and, as a consequence, the probability of encountering empty shells and conspecifics was low. Simulated gastropod predation sites quickly attracted a larger number of hermit crabs than the other sites tested. Aggregations seemed to function as shell exchange markets, as previously suggested for other species: the first attendant took the experimental shell and a chain of shell exchanges among conspecifics followed. Our results show that, in C. erythropus, aggregation is the most efficient tactic for the acquisition of new shells, whereas in other species, such as Pagurus longicarpus, it is associated with exploitation ability due to the intense locomotion. The interspecific plasticity in hermit crabs' behavior is confirmed.
2015
Understanding of the use of shells as an indispensible resource for land hermit crabs increases our understanding of their life history. We investigated shell utilization of the land hermit crab Coenobita rugosus from April 2011 to March 2012 on Phuket Island in the Andaman Coast of Thailand. A total of 1, 322 individuals of C. rugosus were collected (711 males, 507 non-ovigerous females and 104 ovigerous females) using multiple quadrat sampling, and were found to use 63 molluscan shell species, including 62 gastropod shell species from 20 families and one bivalve shell. The diversity of shells used increased with body size from small to medium-sized crabs, but decreased in larger crabs. The most commonly occupied shell species was N. albicilla (19.6 % of crabs). However, N. albicilla used by C. rugosus was not the lightest shell species based on the ratio between internal volume and weight following the “energy saving hypothesis”. Globose shells and those with ovate apertures were ...
Influence of Shell Size and Drilled Holes on Shell Selection in Hermit Crabs
2006
Lacking the hard shell of other crustaceans, most hermit crabs must inhabit empty gastropod shells for protection. The factors influencing their decision of which shell to occupy have been the subject of many studies. It has been found that aspects such as competition, shell type, shell size, shell internal volume, and shell availability all play roles in the final decision. Ideally, a hermit crab would continue moving into larger shells as it grows. However, there is usually a shortage of suitable, available shells. Angel (1999) studied how living in smaller than ideal shells affected the growth rate and risk of predation in hermit crabs.
Hydrobiologia, 2008
Individuals of Pagurus criniticornis in a free-choice situation were experimentally tested under different laboratory conditions. In order to assess the effect of recently occupied shells on the size-and type-preference by hermit crabs, individuals were held for 30 days under one of the following two conditions: (1) excess of shells and (2) absence of shells. The crabs were then allowed to select shells from a wide array of empty gastropod shells of the two most-occupied species, as observed previously in the field: Cerithium atratum and Morula nodulosa. Preferred shell type (species) and size (shell aperture width and length) were correlated with hermit-crab size. The crabs showed a strong (100%) preference for C. atratum shells, demonstrating that recent and past experience did not influence either shell-type or shell-size preferences in this pagurid.
Shell recruitment in the Mediterranean hermit crab Clibanarius erythropus
Journal of Experimental Marine Biology and Ecology, 2009
Gastropod shells are vital for the majority of hermit crab species, being essential for their survival, growth, protection, and reproduction. Given their importance, shells are acquired and transferred between crabs through several modalities. We conducted observations and experiments at the Asinara Island (Sardinia, Italy) to investigate the efficacy of the different behavioral tactics adopted by the hermit crab Clibanarius erythropus to acquire shells, such as: (1) locomotion and activity at different tidal phases; (2) attendance at shell-supplying sites (simulated predation sites with five different odors: live and dead gastropods, live and dead crabs, predator); and interactions with conspecifics in aggregations on simulated gastropod predation sites. In each tidal phase, locomotion was slow (0.7 cm min − 1 ) and, as a consequence, the probability of encountering empty shells and conspecifics was low. Simulated gastropod predation sites quickly attracted a larger number of hermit crabs than the other sites tested. Aggregations seemed to function as shell exchange markets, as previously suggested for other species: the first attendant took the experimental shell and a chain of shell exchanges among conspecifics followed. Our results show that, in C. erythropus, aggregation is the most efficient tactic for the acquisition of new shells, whereas in other species, such as Pagurus longicarpus, it is associated with exploitation ability due to the intense locomotion. The interspecific plasticity in hermit crabs' behavior is confirmed.