2015 Fiscal Year Final Research Report
Abnormal molting? Male hermit crabs shrink their secondary sexual traits responding to predation risk
| Project/Area Number |
25440238
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Ecology/Environment
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| Research Institution | Wakayama University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
YOSHINO Kenji 佐賀大学, 低平地沿岸海域研究センター, 助教 (40380290)
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| Project Period (FY) |
2013-04-01 – 2016-03-31
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| Keywords | 対捕食者反応 / 二次的性形質 / 自然淘汰 / 性淘汰 / ヤドカリ / 脱皮 |
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| Outline of Final Research Achievements |
Secondary sexual traits of males often involve risk of predation because of their conspicuousness. We got results in an experiment using a hermit crab species that only large males with relatively longer claws which are advantageous in inter-male competition for female mates decreased length of the claws by molting under high predation risk, but that small males or females did not. This change of large males may be adaptive to reduce predation risk and then enable to acquire more female mates. Decreasing size by molting is the opposite phenomenon, because molting is known for growing or regenerating the missing claws or legs in some crustaceans.
We conducted another experiment of similar design but increasing stress to hermit crabs. The survival rate of crabs with predator significantly dropped, while that without predator did not. The results indicated that not only predation itself but also existence of predator causes serious stress to the prey animals.
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| Free Research Field |
動物生態学、行動生態学、進化生態学
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