ABSTRACT Bird droppings are an unusual food resource for coprophagous insects and used mostly by opportunistic decomposers. Among them, dung beetles feed mainly on dung, although the species differ in their trophic plasticity. Here we report a record of a dung beetle, Canthidium cf. gracilipes, reaching and manipulating the dropping of a passeriform bird, Dendrocincla fuliginosa (Dendrocolaptidae). The behavior was observed in an urban forest fragment located in the Amazonian city of Manaus, Brazil. Two hours after the bird defecated, the dung beetle reached the dropping and started manipulating them with its fore- and hindlegs. It did not eat the dung, though. For a clear understanding of the relationships between bird droppings and Amazonian dung beetles, it will be important to perform standardized experiments with a wide variety of native dung and carrion types.

RESUMO Excrementos de aves correspondem a um recurso alimentar pouco comum para insetos coprófagos, sendo utilizados geralmente por decompositores oportunistas. Entre eles, os rola bostas se alimentam principalmente de fezes, entretanto a plasticidade alimentar varia entre as espécies. Neste estudo nós reportamos um registro do rola bosta Canthidium cf. gracilipes se aproximando de e manipulando os excrementos de uma ave passeriformes, Dendrocincla fuliginosa (Dendrocolaptidae). O comportamento foi observado em um fragmento localizado na cidade amazônica de Manaus, Brasil. Duas horas depois de que a ave defecou, o rola bosta se aproximou das fezes e começou a manipulá-las com as patas anteriores e posteriores. Entretanto, não se observou consumo do excremento. Para uma compreensão mais clara das relações entre os excrementos de aves e os rola bostas amazônicos, é importante a realização de experimentos padronizados com uma ampla variedade de fezes e carcaças nativas.

Abstract Dung beetles (Scarabaeinae) interact with resources in different ways and are classified according to resource relocation guilds. Dichotomius geminatus (Coprini) and Deltochilum verruciferum (Canthonini) are two of the most abundant and ecologically important species of the semi-arid region of Brazil, and understanding their behaviour may facilitate the comprehension of strategies associated to competition for resources. The aim of the present study was to investigate the behavioural repertoire of D. geminatus (tunneler) and D. verruciferum (roller), in isolation and controlled setting in the Brazilian semi-arid biome, using carrion as a food resource. Our hypothesis was that, due to the distinct food relocation strategies presented by these species, distinct behaviours would occur involving resource utilization. We also compared the behaviour of the two species and investigated the period of diel activity. Both species were more active during the night, but D. geminatus presented a shorter peak of nocturnal activity when compared to D. verruciferum. Although there was activity during the day, feeding was only observed during the night, for both species. During the periods of inactivity, D. verruciferum commonly went underneath the carrion, remaining still. As the target species of the study are very abundant, the differences in behaviour associated with the distinct relocation guilds may indicate a strategy to avoid direct competition.