人口密度は赤鹿の性別比率の変動に影響する
L E Kruuk1, T H Clutton-Brock, S D Albon
1Department of Zoology, University of Cambridge, UK. Loeske.Kruuk@ed.ac.uk
Nature
|June 12, 1999
まとめ
母親の優位性は,高人口密度で赤鹿の子孫の性別比率に影響を与えない. 密度や降雨量などの環境要因は,潜在的に胎児の喪失を通じて,早期の植入前の影響を上回る性比に影響を与えます.
科学分野:
- エコロジー エコロジー エコロジー
- 生殖生物学 生殖生物学
- 哺乳類の研究について
背景:
- 哺乳類の集団は,出生時に性比の歪みをしばしば表しますが,これらのパターンは矛盾しています.
- 性比に影響を与える複数のメカニズムが存在し,その影響は環境条件によって調節されます.
研究 の 目的:
- 環境条件,特に人口密度が,赤鹿 (Cervus elaphus) の母親の優位性と子孫の性別比率の関係にどのように影響するか調査する.
- 環境の変化に対応した性比の変動の背後にあるメカニズムを探求する.
主な方法:
- 赤鹿の長年のデータを分析し,性別比率,人口密度,冬の降雨などの環境変数に焦点を当てました.
- 発見の比較と,類の性別比率の動態に関する既存の文献.
主要な成果:
- 支配的な雌鹿がより多くの雄を産むという以前に観察された適応関係は,高人口密度では存在しない.
- 子孫の性別比 (雄の比) は,人口密度と冬の降雨量,栄養ストレス指標の増加とともに減少した.
- これらの変化は,受精率の低下と相関しており,主なメカニズムとして異なる胎児喪失を示唆しています.
結論:
- 環境要因,特に高密度と降雨量に関連した栄養上のストレスが,母親の優位性効果など,性別比に影響を与える植入前のメカニズムを覆す可能性があります.
- 性比に影響を与える支配的なメカニズムは,約2世代以内に変化する可能性があります.
- 母親の質と雄の子孫の比率の間の肯定的な関連は,荷重能力を下回る類の個体数に限定されているようです.
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