2013 Fiscal Year Final Research Report

A study of the importance of fertilization period for maternal manipulation of offspring traits

Research Project

Project/Area Number	23570020
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Research Field	Ecology/Environment
Research Institution	Tokyo Gakugei University
Principal Investigator	KARINO KENJI 東京学芸大学, 教育学部, 教授 (40293005)
Project Period (FY)	2011 – 2013
Keywords	産子調節 / 受精時期 / 性淘汰 / 配偶者選択 / 行動生態学
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.