Safe or in danger? Time and distance of reaction in hermit crabs to a risk of predation

Author(s):  
Alex Mauricio Mopán-Chilito ◽  
María José Tovar-Gil ◽  
John F. Aristizabal ◽  
Maribel Rojas-Montoya
2015 ◽  
Vol 93 (7) ◽  
pp. 559-565 ◽  
Author(s):  
Carlos Enrique Chávez-Solís ◽  
Guillermina Alcaraz

Hermit crabs respond to predators by hiding in their shells. However, retraction may cause the crab to lose hold of the rock and fall through the water column, and the crab may land with the shell aperture in a different orientation. When the shell is aperture down, hermit crabs return to activity by moving their bodies forward and placing their legs on the ground. In contrast, when the shell is aperture up, crabs need to perform a righting maneuver by extending part of their bodies out of the shell, which makes them more vulnerable to predation. The main goal of this study was to examine the hiding time of the hermit crab Calcinus californiensis Bouvier, 1898 in different shell species under these two different situations to better understand the conflict between the cost of staying in hiding and the risk of predation. The study was conducted in rocky tide pools using seven different shell types that reflect different predator protection and resource value to the crab (based on previous studies). We measured the time required to perform the righting maneuver as a measure of the potential risk incurred when returning to activity. The hiding time with the shell aperture down was not affected by shell species. The requirement to carry out a righting maneuver lengthened the hiding time, which varied in the different shell species according to the time required to recover the natural position. The potential risks associated with the righting time, the protection offered by the shells, and the resource value played an important role in the hiding time of the crabs using different shells. This study shows that hermit crabs are aware of the attributes of the shell and use this information to make decisions about how long to stay hidden after being threatened.


Author(s):  
Xavier Lambin

The dependency of mustelid demographic rates on prey abundance has the potential to cause a strong coupling between predator-prey populations. Data on mustelid dynamics show that such strong reciprocal interactions only materialise in some restricted conditions. Bite-size mustelid predators searching for scarce, depleted prey expose themselves to increased risk of predation by larger predators of small mammal that are themselves searching for similar prey species. As voles or muskrats become scarcer, weasels and mink searching for prey over larger areas become increasingly exposed to intra-guild predation, unless they operate in a habitat refuge such as the sub-nivean space. Where larger predators are sufficiently abundant or exert year-round predation pressure on small mustelids, their impact on mustelids may impose biological barrier to dispersal that are sufficient to weaken the coupling between small mustelids and their rodent prey, and thus impose a degree of top down limitation on mustelids.


1994 ◽  
Vol 15 (4) ◽  
pp. 413-416 ◽  
Author(s):  
H. Saint Girons

AbstractIf one accepts that the number of times that vipers are observed in the field in any given season is an indirect measure of the overall risk of predation run by such diurnal predators hunting by vision, the results obtained in this study show that risk of predation is particularly high in males during the period of mating and in females when pregnant.


2021 ◽  
pp. 1-12
Author(s):  
Morgane Allanic ◽  
Misato Hayashi ◽  
Takeshi Furuichi ◽  
Tetsuro Matsuzawa

Grooming site preferences have been relatively well studied in monkey species in order to investigate the function of social grooming. They are not only influenced by the amount of ectoparasites, but also by different social variables such as the dominance rank between individuals or their levels of affiliation. However, studies on this topic mainly come from monkey species, with almost no report on great apes. This study aimed to explore whether body site and body orientation preferences during social grooming show species-specific differences (bonobos vs. chimpanzees) and environment-specific differences (captivity vs. wild). Results showed that bonobos groomed the head, the front and faced each other more often than chimpanzees, while chimpanzees groomed the back, anogenitals and more frequently in face-to-back positions. Moreover, captive individuals were found to groom facing one another more often than wild ones, whereas wild individuals groomed the back and in face-to-back positions more. While future studies should expand their scope to include more populations per condition, our preliminary 2 by 2 comparison study highlights the influence of (i) species-specific social differences such as social tolerance, social attention and facial communication, and (ii) socioenvironmental constraints such as risk of predation, spatial crowding and levels of hygiene, that might be the two important factors determining the grooming patterns in two <i>Pan</i>species.


Mammalia ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Brian Keane ◽  
Phillip J. Long ◽  
Yasmeen Fleifil ◽  
Nancy G. Solomon

AbstractBehavioral changes that reduce the risk of predation in response to predator-derived odor cues are widespread among mammalian taxa and have received a great deal of attention. Although voles of the genus Microtus are staples in the diet of many mammalian predators, including domestic cats (Felis catus), there are no previous studies on vole space utilization and activity levels in response to odor cues from domestic cats. Therefore, the objective of our study was to investigate responses of adult prairie voles (Microtus ochrogaster) living in semi-natural habitats to odor cues from domestic cat excreta. Contrary to expectations, neither adult males or females showed significant changes in space use or willingness to enter traps in response to cat odors. One hypothesis to explain our results are that prairie voles have not co-evolved with domestic cats long enough to respond to their odors. Other possible explanations include whether levels of odors in the environment were sufficient to trigger a response or that the perceived risk of predation from odor cues alone did not outweigh relative costs of changing space use and activity levels. Future studies should consider multiple factors when determining what cues are sufficient to elicit antipredatory behavior.


Palaios ◽  
1987 ◽  
Vol 2 (4) ◽  
pp. 313 ◽  
Author(s):  
Robert W. Frey
Keyword(s):  

Evolution ◽  
1991 ◽  
Vol 45 (6) ◽  
pp. 1301 ◽  
Author(s):  
C. W. Cunningham ◽  
L. W. Buss ◽  
Cort Anderson
Keyword(s):  

Author(s):  
Paula Schirrmacher ◽  
Christina C. Roggatz ◽  
David M. Benoit ◽  
Jörg D. Hardege

AbstractWith carbon dioxide (CO2) levels rising dramatically, climate change threatens marine environments. Due to increasing CO2 concentrations in the ocean, pH levels are expected to drop by 0.4 units by the end of the century. There is an urgent need to understand the impact of ocean acidification on chemical-ecological processes. To date, the extent and mechanisms by which the decreasing ocean pH influences chemical communication are unclear. Combining behaviour assays with computational chemistry, we explore the function of the predator related cue 2-phenylethylamine (PEA) for hermit crabs (Pagurus bernhardus) in current and end-of-the-century oceanic pH. Living in intertidal environments, hermit crabs face large pH fluctuations in their current habitat in addition to climate-change related ocean acidification. We demonstrate that the dietary predator cue PEA for mammals and sea lampreys is an attractant for hermit crabs, with the potency of the cue increasing with decreasing pH levels. In order to explain this increased potency, we assess changes to PEA’s conformational and charge-related properties as one potential mechanistic pathway. Using quantum chemical calculations validated by NMR spectroscopy, we characterise the different protonation states of PEA in water. We show how protonation of PEA could affect receptor-ligand binding, using a possible model receptor for PEA (human TAAR1). Investigating potential mechanisms of pH-dependent effects on olfactory perception of PEA and the respective behavioural response, our study advances the understanding of how ocean acidification interferes with the sense of smell and thereby might impact essential ecological interactions in marine ecosystems.


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