A formação, recrutamento e manutenção de trilhas em formigas cortadeiras do gênero Atta é controlada quimicamente e envolve a participação de diferentes castas. Todavia, são escassos os estudos sobre a dinâmica das castas sob diferentes fontes de estímulos para a colônia, e como isso interfere na deposição de trilhas químicas. O presente trabalho visou compreender a influência de diferentes fontes de estímulos no padrão químico de deposição das trilhas, bem como no comportamento de recrutamento, forrageamento e defesa das operárias em Atta sexdens rubropilosa (Hymenoptera: Formicidae). Os resultados indicaram que houve variação do perfil etológico e alocação de tarefas desempenhadas pelos indivíduos presentes na colônia, de acordo com a fonte de estímulo. Neste caso foram oferecidos uma fonte de estímulo atrativa (\"pétalas de rosas\") e outra de agressividade (\"rainha de outra colônia\"). Além disso, os perfis químicos observados nas trilhas variaram qualitativamente e quantitativamente de acordo com os estímulos oferecidos. Estes dados sugerem que as operárias de A. sexdens rubropilosa seriam capazes de manejar quimicamente seu feromônio de trilha para informar e alterar o comportamento de suas companheiras de ninho, de acordo com a fonte de estímulo em que foram expostas. / Formation, recruitment and maintenance of trail in Atta leaf-cutting ants are chemically controlled and involve participation of different castes. Nevertheless, studies on caste dynamic under different stimuli to the colony are scarce, and how it interferes in the chemical deposition of the trail. This investigation aimed to understand how different source of stimuli influence the chemical pattern of trail marking as well as the recruitment, foraging and defense behavior by workers in Atta sexdens rubropilosa (Hymenoptera: Formicidae). Results indicate variation in the ethological profile and task allocation performed by the colony individuals, according to the stimuli source. In this case, it was offered an attractive stimulus source (\"rose petals\") and an aggressive one (\"other colony queen\"). Moreover, the chemical profiles of the trail varied qualitatively and quantitatively in response to the stimuli they were exposed. These data suggest that A. sexdens rubropilosa workers would be able to chemically manipulate their trail pheromone with aim to inform and alter their nestmate behavior in response to the exposed stimuli source.

A formação, recrutamento e manutenção de trilhas em formigas cortadeiras do gênero Atta é controlada quimicamente e envolve a participação de diferentes castas. Todavia, são escassos os estudos sobre a dinâmica das castas sob diferentes fontes de estímulos para a colônia, e como isso interfere na deposição de trilhas químicas. O presente trabalho visou compreender a influência de diferentes fontes de estímulos no padrão químico de deposição das trilhas, bem como no comportamento de recrutamento, forrageamento e defesa das operárias em Atta sexdens rubropilosa (Hymenoptera: Formicidae). Os resultados indicaram que houve variação do perfil etológico e alocação de tarefas desempenhadas pelos indivíduos presentes na colônia, de acordo com a fonte de estímulo. Neste caso foram oferecidos uma fonte de estímulo atrativa (\"pétalas de rosas\") e outra de agressividade (\"rainha de outra colônia\"). Além disso, os perfis químicos observados nas trilhas variaram qualitativamente e quantitativamente de acordo com os estímulos oferecidos. Estes dados sugerem que as operárias de A. sexdens rubropilosa seriam capazes de manejar quimicamente seu feromônio de trilha para informar e alterar o comportamento de suas companheiras de ninho, de acordo com a fonte de estímulo em que foram expostas. / Formation, recruitment and maintenance of trail in Atta leaf-cutting ants are chemically controlled and involve participation of different castes. Nevertheless, studies on caste dynamic under different stimuli to the colony are scarce, and how it interferes in the chemical deposition of the trail. This investigation aimed to understand how different source of stimuli influence the chemical pattern of trail marking as well as the recruitment, foraging and defense behavior by workers in Atta sexdens rubropilosa (Hymenoptera: Formicidae). Results indicate variation in the ethological profile and task allocation performed by the colony individuals, according to the stimuli source. In this case, it was offered an attractive stimulus source (\"rose petals\") and an aggressive one (\"other colony queen\"). Moreover, the chemical profiles of the trail varied qualitatively and quantitatively in response to the stimuli they were exposed. These data suggest that A. sexdens rubropilosa workers would be able to chemically manipulate their trail pheromone with aim to inform and alter their nestmate behavior in response to the exposed stimuli source.

The Wood Thrush (Hylocichla mustelina) is declining throughout its range, yet is capable of persisting in both contiguous forests and small forest patches surrounded by human suburban development. Thus, it is an ideal species for gaining insight into the effects of suburbanization on migrant songbirds. I investigated two aspects of Wood Thrush nesting ecology: nest ectoparasites and nest defense behavior in order to determine if suburbanization influences either aspect. Nests from suburban forests had fewer haematophagous mites, though the abundance of haematophagous blowfly larvae did not differ between suburban and contiguous forests. There was no relationship between the abundance of mites and nest site characteristics, though blowfly abundance may be related to nesting substrate species. Parasites had little effect on nestling condition. In regard to nest defense, suburban Wood Thrushes had shorter flight initiation distances and mounted more active defenses during initial nest visits than birds nesting in contiguous forests, suggesting a previously-established sensitization response to human disturbances in suburban birds. I found no consistent shifts in aggression over subsequent nest visits in either habitat type, suggesting that throughout the breeding season, Wood Thrushes neither habituate nor sensitize further to repeated human disturbances. My results suggest that Wood Thrushes nesting in suburban forest patches are subject to fewer nest ectoparasites and defend their nests more aggressively than conspecifics nesting in contiguous forests. These results draw attention to the fact that although Wood Thrushes persist in both rural and suburban habitats, their nesting ecology may be different between these habitat types.