Redução do forrageio do iguana-negro-de-cauda-espinhosa, Ctenosaura similis (Sauria: Iguanidae), na presença de estímulos do predador

The presence of a predator may have direct and indirect effects on the behavior of the prey. Although altered behavior may help prey avoid predators, it also can have a potential impact on critical activities such as foraging. Predator-prey interactions are routinely studied in laboratory-based experiments owing to the perceived difficulties of conducting such experiments in natural settings. We conducted an experimental study under field conditions in Palo Verde National Park in northwestern Costa Rica to assess behavioral responses of Black Spiny-tailed Iguanas (Ctenosaura similis) to the presence of predators and predator cues. Free-roaming iguanas were offered mango in designated areas in the presence of a predator (Boa constrictor), a predator cue (B. constrictor feces), and a control (no predator or predator cue). Results indicate that iguanas reduced their foraging efforts in the presence of both a predator and its cue.A presença de um predador pode exercer efeitos diretos e indiretos sobre o comportamento da presa. Embora a alteração do comportamento possa ajudar a presa a evitar predadores, pode também ter um impacto potencial sobre atividades críticas, como o forrageio. As interações predador-presa são comumente estudadas em experimentos de laboratório devido às dificuldades em conduzir experimentos sob condições naturais. Conduzimos um estudo experimental em campo no Parque Nacional Palo Verde, no noroeste da Costa Rica, para avaliar as respostas dos iguanas-negros-de-cauda-espinhosa (Ctenosaura similis) à presença de predadores e de seus estímulos. Oferecemos manga a iguanas livres em áreas pré-estabelecidas na presença de um predador (Boa constrictor), de um estímulo do predador (fezes de B. constrictor) e em uma áreacontrole (sem predador ou estímulo). Os resultados indicam que os iguanas reduziram seus esforços de forrageio tanto na presença do predador como de seu estímulo

Reduced foraging in the presence of predator cues by the Black Spiny-tailed Iguana, Ctenosaura similis (Sauria: Iguanidae)

The presence of a predator may have direct and indirect effects on the behavior of the prey. Although altered behavior may help prey avoid predators, it also can have a potential impact on critical activities such as foraging. Predator-prey interactions are routinely studied in laboratory-based experiments owing to theperceived difficulties of conducting such experiments in natural settings. We conducted an experimental study under field conditions in Palo Verde National Park in northwestern Costa Rica to assess behavioral responses of Black Spiny-tailed Iguanas (Ctenosaurasimilis) to the presence of predators and predator cues. Free-roaming iguanas were offered mango in designated areas in the presence of a predator (Boa constrictor), a predator cue (B. constrictor feces), and a control (no predator or predator cue). Results indicate that iguanas reduced their foraging efforts in the presence of both a predator and its cue

A Comprehensive Analysis of Replicative Lifespan in 4,698 Single-Gene Deletion Strains Uncovers Conserved Mechanisms of Aging

Many genes that affect replicative lifespan (RLS) in the budding yeast Saccharomyces cerevisiae also affect aging in other organisms such as C. elegans and M. musculus. We performed a systematic analysis of yeast RLS in a set of 4,698 viable single-gene deletion strains. Multiple functional gene clusters were identified, and full genome-to-genome comparison demonstrated a significant conservation in longevity pathways between yeast and C. elegans. Among the mechanisms of aging identified, deletion of tRNA exporter LOS1 robustly extended lifespan. Dietary restriction (DR) and inhibition of mechanistic Target of Rapamycin (mTOR) exclude Los1 from the nucleus in a Rad53-dependent manner. Moreover, lifespan extension from deletion of LOS1 is nonadditive with DR or mTOR inhibition, and results in Gcn4 transcription factor activation. Thus, the DNA damage response and mTOR converge on Los1-mediated nuclear tRNA export to regulate Gcn4 activity and aging