Sex-specific foraging behaviour in a seabird with reversed sexual dimorphism: the red-footed booby
Sex-specific foraging behaviour in a seabird with reversed sexual dimorphism: the red-footed booby
复制标题
DOI：
10.1007/s00442-005-0226-x
复制
发表时间：
2005
期刊：
影响因子：
2.7
通讯作者：
H. Weimerskirch;M. Corre;Y. Ropert‐Coudert;A. Kato;F. Marsac
中科院分区：
文献类型：
--
作者：
H. Weimerskirch;M. Corre;Y. Ropert‐Coudert;A. Kato;F. Marsac
大多数试图解释RSD进化的假说都认为觅食能力的大小差异是最重要的，但关于觅食行为的性别差异的研究仍然很少。我们通过几个小型活动和遥测记录仪比较了具有RSD的海鸟物种中雄性和雌性的觅食行为。红脚鲣鸟中，雄性比雌性小5%，轻15%，但尾巴比雌性长。雄性和雌性在窝里孵蛋的时间差不多。在海上觅食时，雄性和雌性在海水中觅食的时间相似，在相似的区域觅食，在飞行中觅食的时间比例相似，捕食大小相似的猎物——飞鱼和飞乌贼。然而，与雄性相比，雌性在孵化期间的活动范围更远（85公里对50公里），而且主要在觅食旅程的末端觅食，而雄性则在整个旅程中都积极觅食。雄性比雌性活跃得多，着陆和潜水的频率更高。在研究期间，雄性体重下降，而雌性没有明显变化。这些结果表明，雄性和雌性红脚鲣鸟在觅食行为的几个方面存在差异。虽然研究中发现的一些差异可能是雌性体型较大的直接结果，即雌性的速度略高，深度略深，但其他差异明显表明两性之间的觅食策略不同。雄性的体型较小，尾巴较长，这赋予了它们更高的灵活性，并使它们能够占据与雌性不同的觅食生态位。不同的觅食策略导致雄性的高觅食努力可能是繁殖期雄性数量迅速减少的原因。这些结果表明，觅食差异可能是鲣鸟繁殖投资差异的原因，并可能参与RSD的进化和维持。
Most hypotheses attempting to explain the evolution of reversed sexual dimorphism (RSD) assume that size-related differences in foraging ability are of prime importance, but the studies on sex-specific differences in foraging behaviour remain scarce. We compare the foraging behaviour of males and females in a seabird species with a RSD by using several miniaturised activity and telemetry loggers. In red-footed boobies males are 5% smaller and 15% lighter than females, but have a longer tail than females. Both sexes spend similar time on the nest while incubating or brooding. When foraging at sea, males and females spend similar time foraging in oceanic waters, forage in similar areas, spend similar proportion of their foraging trip in flight, and feed on similar prey—flying fishes and flying squids—of similar size. However, compared to males, females range farther during incubation (85 km vs. 50 km), and furthermore feed mostly at the extremity of their foraging trip, whereas males actively forage throughout the trip. Males are much more active than females, landing and diving more often. During the study period, males lost mass, whereas females showed no significant changes. These results indicate that males and females of the red-footed boobies differ in several aspects in their foraging behaviour. Although some differences found in the study may be the direct result of the larger size of females, that is, the slightly higher speeds and deeper depths attained by females, others indicate clearly different foraging strategies between the sexes. The smaller size and longer tail of males confer them a higher agility, and could allow them to occupy a foraging niche different from that of females. The higher foraging effort of males related to its different foraging strategy is probably at the origin of the rapid mass loss of males during the breeding period. These results suggest that foraging differences are probably the reason for the differential breeding investment observed in boobies, and are likely to be involved in the evolution and maintenance of RSD.