| Project/Area Number |
25440169
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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 |
Animal physiology/Animal behavior
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| Research Institution | Shimane University |
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Principal Investigator |
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| Project Period (FY) |
2013-04-01 – 2016-03-31
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| Project Status |
Completed (Fiscal Year 2015)
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| Budget Amount *help |
¥5,200,000 (Direct Cost: ¥4,000,000、Indirect Cost: ¥1,200,000)
Fiscal Year 2015: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2014: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2013: ¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000)
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| Keywords | mating behavior / promiscuity / sneaker males / reproduction / spermatozoa / glycogen / 代替繁殖戦術 / スニーキング / 精子進化 / 交尾後性選択 / 精子寿命 / 解糖系 / ヤリイカ / 精子競争 / 生殖戦術 / 雄2型 / スニーキング交接 / 受精 / 乳酸排出 / 乱交 / 走化性 |
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| Outline of Final Research Achievements |
In squids, two types of male mating behavior are causally associated with adult body size. Males inseminate promiscuously with the same females; large “consort” males internally, and small “sneaker” males externally. Previously we found that in Heterololigo bleekeri, only sneaker spermatozoa are able to swarm, suggesting that a swarming trait might have arisen in sneakers as a “sperm cooperation” strategy among sibling sperm to compete with consorts, or as a consequence of adaptation to external fertilization. Notably, only sneaker spermatozoa inseminated long before egg spawning can be stored in the seminal receptacle. We found that they exhibited greater persistence in fertilization competence and flagellar motility than consort ones owning to larger amount of flagellar glycogen. These results, together with comparative omics analyses, suggest that postcopulatory reproductive contexts define sperm longevity by modulating the inherent energy levels and metabolic pathways.
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