Bergmann's rule is followed at multiple stages of postembryonic development in a long-distance migratory songbird.

摘要: Bergmann's rule is a well-established, ecogeographical principle that states body size varies positively with latitude, reflecting the thermoregulatory benefits of larger bodies as temperatures decline. However, this does not seem to easily apply migratory species are able avoid extreme during winter at higher latitudes. Further, little known about ontogeny relationship across life stages or how it influenced by ongoing global climate change. To address these knowledge gaps, we assessed contemporary between latitude and in long-distance species, prothonotary warbler (Protonotaria citrea) (egg adult) on their breeding grounds. We also measured historic eggs (1865-1961) assess if stage has changed over time. In accordance rule, found positive mass all post-embryonic stages, from early nestling through adulthood. observed same predicted pattern eggs, but exhibited reverse (negative) relationship. suggest results indicate genetic component speculate selection for altricial nestlings increases may possibly drive even rare cold weather events cause mortality stages. Furthermore, opposite relationships dependent time period, be related rapidly warming environments latitudes associated Although unclear what mechanism(s) would allow recent reversal (but still its maintenance later stages). This evidence suggests anthropogenic change process altering one longest-standing principles ecology.