Low food abundance prior to breeding results in female-biased sex allocation in Tengmalm’s Owl ( Aegolius funerus )

摘要: Parents can enhance their fitness by favouring that sex whose reproductive value is expected to be highest. In species in which females are the larger with potentially greater returns, one assume parents should bias investment toward daughters increase daughters’ (i.e. age-specific expectation of all present and future offspring) and, thereby, indirectly own inclusive fitness. study reported here, we investigated allocation Tengmalm’s Owl (Aegolius funereus), a bird pronounced female-biased sexual size dimorphism than males. Assuming parental would have greatest effect on daughters, hypothesized favoured good conditions sons poor conditions. Our was conducted Czech Republic over seven breeding seasons (2006–2012). total, 205 nestlings from 52 nests were sexed. The mean nestling ratio, 48.5 ± 4.6% (± standard error), did not depart parity, identify any variable related it. However, find at fledging (1) body mass female offspring approximately 8% heavier male offspring, (2) surprisingly, tended decreasing prey abundance autumn, i.e. prior breeding. One possible explanation this “carry-over effect” increased maximize survival environment. This could supported sex-specific adult’s condition success. Whereas number fledglings increasing age mother, it also wing length father. These results indicate large may mainly important for reproduction, while success independent or even associated small size. To best our knowledge, first found such positive, relatively long-lasting, carry-over pre-breeding species.