Velando Alberto, Drummond Hugh, Torres Roxana
Universidade de Vigo Departamento de Ecoloxía e Bioloxía Animal, 36310 Vigo, Spain.
Proc Biol Sci. 2006 Jun 22;273(1593):1443-8. doi: 10.1098/rspb.2006.3480.
This study reports an experimental confirmation of the terminal investment hypothesis, a longstanding theoretical idea that animals should increase their reproductive effort as they age and their prospects for survival and reproduction decline. Previous correlational and experimental attempts to test this hypothesis have yielded contradictory results. In the blue-footed booby, Sula nebouxii, a long-lived bird, after initial increase, male reproductive success declines progressively with age. Before laying, males of two age classes were challenged with lipopolysaccharide to elicit an immune response, which induced symptoms of declining survival prospects. Reproductive success of immune-challenged mature males fell, while that of immune-challenged old males showed a 98% increase. These results demonstrate that senescent males with poor reproductive prospects increase their effort when those prospects are threatened, whereas younger males with good reproductive prospects do not.
本研究报告了对终端投资假说的实验验证，这是一个长期存在的理论观点，即动物应随着年龄增长以及生存和繁殖前景的下降而增加繁殖投入。此前检验该假说的相关研究和实验尝试得出了相互矛盾的结果。在蓝脚鲣鸟（Sula nebouxii）这种长寿鸟类中，雄性繁殖成功率在经历初期增长后会随着年龄的增长而逐渐下降。在产卵前，对两个年龄组的雄性蓝脚鲣鸟注射脂多糖以引发免疫反应，该反应会引发生存前景下降的症状。受到免疫挑战的成熟雄性的繁殖成功率下降，而受到免疫挑战的老年雄性的繁殖成功率则提高了98%。这些结果表明，繁殖前景不佳的衰老雄性在繁殖前景受到威胁时会增加繁殖投入，而繁殖前景良好的年轻雄性则不会。
