| Budget Amount *help |
¥5,590,000 (Direct Cost: ¥4,300,000、Indirect Cost: ¥1,290,000)
Fiscal Year 2014: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2013: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
Fiscal Year 2012: ¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000)
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| Outline of Final Research Achievements |
Lepidopteran males including swallowtail butterflies transfer two types of sperm, nucleated eupyrene and non-nucleated apyrene sperm, within a single spermatophore. Both types of sperm migrate to the spermatheca. The cheap filler hypothesis has been proposed on the role of apyrene sperm in the polyandrous species, where motile apyrene sperm in the spermatheca reduce female receptivity of re-mating. Males of monandrous species also produce apyrene sperm, migrating to the spermatheca. Sperm dynamics and the motility of apyrene sperm in the spermatheca after copulation were examined in polyandrous and monandrous species. In the polyandrous species, apyrene sperm disappeared from the spermatheca in a couple of days after the copulation. In the monandrous species, although apyrene sperm remain in the spermatheca long time after copulation, they lost the motility soon after the migration to the spermatheca. Then, alternative hypotheses of the role of apyrene sperm was discussed.
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