Host utilization of the Brazil nut family (Lecythidaceae) by sympatric wood-boring species of Palame (Coleoptera, Cerambycidae, Lamiinae, Acanthocinini)

Abstract

Estimates of the total number of arthropod species in existence are based, in part, upon assumptions about both the host specificity of tropical insects and their restriction to the forest canopy. It has been difficult to evaluate these estimates because of the paucity of available data. A newly discovered association between wood-boring beetles (Cerambycidae) and their host plants in the Brazil nut family (Lecythidaceae) inspired a year-long rearing project in the Neotropical rain forest of French Guiana. Branches severed from five species of Lecythidaceae yielded 1813 cerambycids belonging to 37 species. Three cerambycid species–Palame anceps (Bates), P. crassimana Bates, and P. mimetica Monné–accounted for almost half of the individuals reared. Each demonstrated a different pattern of host fidelity. Palame crassimana emerged from four of the five potential hosts, P. anceps emerged exclusively from a single host, and P. mimetica made a seasonal change in host affiliation. Although Palame spp. emerged from both ground level and canopy branches, they made a seasonal shift in stratum: they reproduced at both levels during the dry season, but exclusively at canopy level during the rainy season. Even specialized tropical insects may show greater flexibility in host utilization than some current hypotheses suggest.