| Budget Amount *help |
¥5,330,000 (Direct Cost: ¥4,100,000、Indirect Cost: ¥1,230,000)
Fiscal Year 2013: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2012: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2011: ¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000)
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| Research Abstract |
Female guppies Poecilia reticulata, a live-bearing fish, are known to adjust the number of offspring according to the attractiveness of their mates. In this study, I tested a hypothesis that females may adjust the number of offspring by manipulating fertilization period of eggs. Results of this study indicated that females fertilized their eggs immediately after mating with males, when the males were preferred by the females in female preference test. On the other hand, some females did not fertilize eggs even 22 days after mating. These females held many ripe eggs according to the extent of sexual ornamentation of their mates. These results suggest that female guppies may manipulate fertilization period and the number of ripe eggs until fertilization depending on the attractiveness of their mates.
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