Fig 1 - uploaded by Tsunenori Koga
Content may be subject to copyright.
Predation intensity of the portunid crab Charybdis japonica on the hermit crab Diogenes nitidimanus inAUmbonium-type andB Batillaria-type shells, according to shell size and season.
Source publication
Portunid crabs are strong predators in shore ecosystems, and often prey on hermit crabs. In a previous study, we observed the loss of larger individuals of the hermit crab Diogenes nitidimanus during the mid-reproductive season. Therefore, we experimentally investigated predation intensity of the portunid crabs Charybdis japonica and Portunus pelag...
Similar publications
Crab-eating mongooses (Herpestes urva) are widely distributed across Southeast Asia. In Taiwan, the mongoose (H. urva formosanus, endemic subspecies) is a protected species under the Wildlife Protection Act. Crab-eating mongooses have been observed near streams, riversides, agricultural lands, and shallow mountain areas. Additionally, as described...
Escape decisions to predators are influenced by aspects such as
prey’s visual perspective, in which visual cues are essential to detect
and react to predators. Crabs use the visual sense to detect and
scaling potential threats. Here, we evaluate the escaping response
of free-ranging Pacific hermit crab (Coenobita compressus) after
showing them stim...
Many aquatic invertebrates adjust their behavior to the degree of predation risk, which can be inferred from various sensory cues. We assessed the ability of the hermit crab Pagurus minutus to process different types of cues during predator avoidance and to discriminate between predators and non-predators by measuring the length of time that the he...
Citations
... Charybdis japonica is a highly carnivorous portunid crab that reaches about 80 mm in carapace width and is distributed across Japan, Korea, and China (Miyake 1983) from estuarine tidal flats to subtidal zones up to a depth of 45 m. The species is a major predator of hermit crabs in the Waka River estuary (Sakata et al. 2020). Clibanarius infraspinatus is a relatively large diogenid hermit crab that reaches about 19 mm in shield length and is distributed across Japan, southern China, and the Philippines (Miyake 1982). ...
... The elements of the box plot are as follows: thick black lines, means; boxes, interquartile ranges; whiskers, 5th and 95th percentiles; open circles, outliers 2014), and is likely to do the same when targeting hermit crabs occupying T. funebralis shells as in the experiment conducted by Rosen et al. (2009). Meanwhile, the predator Charybdis japonicus chosen for our experiment is capable of crushing the shells of several gastropod species used by hermit crabs in the Waka River estuary, but cannot easily crush the Batillaria shells (Sakata et al. 2020) occupied by P. minutus in our experiments. Hence, whereas fleeing is likely to be the optimal choice for P. granosimanus, P. minutus individuals housed in Batillaria shells are likely to be safe inside their shells, which could explain the difference in hiding times between the two species. ...
... japonica, which can prey even on deeply burrowed bivalves such as Ruditapes philippinarum, probably by relying on chemical cues and searching through the sand with its non-paddle ambulatory legs (Kimura 2005;Takahashi et al. 2016). Hence, withdrawing into its shell and waiting for any predators to give up would be a better tactic for P. minutus inhabiting robust Batillaria shells (Sakata et al. 2020), but fleeing or hiding in refugia would be more effective for P. granosimanus, reflecting the long hiding times observed for P. minutus and short hiding times for P. granosimanus. Future comparisons of P. minutus behavior in Batillaria as compared to other non-robust shell species could show whether this is the case. ...
Many aquatic invertebrates adjust their behavior to the degree of predation risk, which can be inferred from various sensory cues. We assessed the ability of the hermit crab Pagurus minutus to process different types of cues during predator avoidance and to discriminate between predators and non-predators by measuring the length of time that the hermit crabs remained retracted within their shells (hiding time) after exposure to visual cues, chemical cues, or both. Video images were used as visual cues, and water from aquaria holding predators or non-predators were used as chemical cues. The predator species was the portunid crab Charybdis japonica, and the non-predator species was the hermit crab Clibanarius infraspinatus. Natural seawater and background video were used as controls. Test individuals were exposed to each cue for 100 s. Both visual and chemical predator cues significantly increased hiding time in comparison to the controls, whereas non-predator cues did not significantly affect hiding time, indicating that P. minutus can discriminate between predators and non-predators from both visual and chemical cues. However, exposure to visual and chemical cues simultaneously did not significantly lengthen hiding times in comparison to exposure to a single cue type, indicating that there is no dominance in risk hierarchy between visual and chemical cues, and that P. minutus integrates information from both types of cues as if they were a single cue. We discuss the differences in our results from those previously obtained with a similar experimental design for the hermit crab P. granosimanus.
Significance statement
Animals must identify the most informative cues and integrate information from multiple cues to make the appropriate decisions for predator avoidance. When exposed to two types of cues, prey animals may assess them as a sign of multiple nearby predators even if the cues come from a single predator, leading to stronger response to two simultaneous cues than to either cue in isolation. It is still possible that prey animals integrate information from multiple cues as originating from a single predator. However, most studies have not fully considered this possibility. Our study revealed that P. minutus were able to discriminate between predators and non-predators from visual and chemical cues in isolation, but did not respond stronger to the simultaneous cues than to either cue in isolation. Our results suggest an example of non-additive response to multiple cues due to information redundancy among cue types.
