Songbirds must annually undergo two energetically demanding but important activities: breeding and feather molt. Due to the high energetic investment that each demands, these two events are generally not carried out simultaneously. However, substantial variation in the level of annual reproductive investment among populations may result in variation in molt-breeding overlap between them. With the goal of understanding whether different songbird populations overlap molt and breeding, and, if so, to determine directions for research on the potential tradeoffs involved, we describe the relationship between clutch size, molt, and energetic condition within a genus of New World Flycatchers (Tyrannus). Of 219 Flycatchers sampled, only one individual molted flight feathers while breeding, suggesting that molting flight feathers and breeding simultaneously is too energetically expensive at any clutch size. However, some Flycatchers molted body feathers during the breeding season. When we tested for an effect of clutch size, sex and energetic condition on body molt intensity during the breeding season, only clutch size and sex had significant effects, with a negative effect of clutch size on body molt intensity in males but not in females. Based on these results, we develop a set of hypotheses to guide future studies on the potential tradeoffs between investment in reproduction and molt.
Morcegos em teias da aranha-gigante Nephilingis cruentata (Fabricius, 1775) (Araneae: Nephilidae) no Brasil. Em todo o mundo morcegos são vítimas principalmente de vertebrados, mas também são atacados por invertebrados. Relatamos aqui dois casos de morcegos enredados em teias da aranha-gigante Nephilingis cruentata, no sudeste do Brasil. No primeiro, ocorrido em dezembro de 2012, uma fêmea de Eptesicus diminutus foi encontrada morta, e no segundo, ocorrido em março de 2013, um macho de Tadarida brasiliensis foi retirado vivo da teia e liberado. Os animais não apresentavam marcas de predação e ambos os eventos foram registrados após fortes chuvas. Suspeita-se que os morcegos podem ter se emaranharado nas teias quando buscavam abrigo da chuva ou caçavam insetos. Mesmo que esses morcegos não tenham sido predados, esta espécie de aranha não deve ser descartada como um predador oportunista de pequenos morcegos, como observado em outras regiões fora do Brasil.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.