Evolution and function of mate competition among females in monogamous birds.

2020 Fiscal Year Final Research Report

• Project/Area Number: 19K23764
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0703:Biology at organismal to population levels and anthropology, and related fields
• Research Institution: Osaka City University
• Principal Investigator: Nishida Yuusuke 大阪市立大学, 大学院理学研究科, 特任講師 (70845916)
• Project Period (FY): 2019-08-30 – 2021-03-31
• Keywords: 性的対立 / モズ / 貯食

Outline of Final Research Achievements

Reproductive investment theory predicts that mating competition among same sex and mutual mate choice occur in monogamous species where both parents foster offspring. In addition, sexual conflict will occur simultaneously. Bull-headed shrike is a monogamous bird and pair bond is stronger in the post-mating period than in the pre-mating period. sexual conflict is predicted to occur in the pre-mating periods than the post-mating period. The male shrike store food by impaling its prey on the branches of trees. In the pre-mating period males stored 90.1 ± 15.1% of food acquired in conspicuous places, while in the post-mating period they stored 89.8 ± 17.6% of food acquired in concealed places. The males recovered 97.5 ± 7.1% of the caches in concealed places and the males and paring females 57.7 ± 33.4% of the caches in conspicuous places. It is suggested that male bull-headed shrikes concealed caches to prevent females from retrieving it during the pre-mating period.

Free Research Field

行動生態学

Academic Significance and Societal Importance of the Research Achievements

繁殖投資理論によると、両親で子育てし、繁殖投資量の性差の小さい一夫一妻の種では、雄間競争、雌間競争、雌雄の相互配偶者選択が生じるとされる。さらには、雌雄それぞれが自身の適応度を最大化しようと、雌雄間の利害対立も同時に生じると予想されるが、検証例は少ない。モズは一夫一妻の鳥類で、ペアボンドは交尾後の時期は強固になるが、交尾前の時期は不安定であるため、交尾前の時期で性的対立が生じる可能性がある。モズの雄は交尾前には隠蔽貯蔵することを発見し、さらに隠蔽貯蔵は性的対立で進化した行動であることを世界に先がけて発見した。