Temporal distribution, seed damage and notes on the natural history of Acanthoscelides quadridentatus and Acanthoscelides winderi (Coleoptera: Chrysomelidae: Bruchinae) on their host plant, Mimosa setosa var. paludosa (Fabaceae: Mimosoideae), in the Brazilian Cerrado

Abstract

ABSTRACTThe seed beetles, Acanthoscelides quadridentatus and Acanthoscelides winderi are here recorded for the first time feeding on seeds of Mimosa setosa var. paludosa in the Brazilian Cerrado. Our main aims were to describe the temporal distribution, seed damage, and notes on the natural history of these two species on their host plant. We hypothesised that: (a) healthy seeds from infested fruits would have worse germination rate than healthy seeds from noninfested fruits, and (b) females of seed beetles would lay more eggs on large fruits. We made field observations and an experimental field study with the presence of seed beetles versus their exclusion on plants. Results revealed that seed beetles are synchronised with fruiting, with a temporal partitioning in occurrence. Attacked seeds did not germinate, whereas healthy seeds from infested fruits had worse germination rate than healthy seeds from noninfested fruits. Females of seed beetles laid more eggs on large fruits. These results suggest that seed beetles avoid competition through a temporal partitioning curcial for their coexistence, and select large fruits to oviposit as these fruits probably provide more food resource for their offspring. Furthermore, plants might perceive seed beetles’ damage and then reduce resource allocation on infested fruits.