Revisiting trends in morphology of antennal sensilla in scarabaeoid beetles

Abstract Phytophagous scarab beetles associated with angiosperms have characteristically enlarged lamellate antennae and exhibit a striking morphological variation of sensilla. In this study, we compared the morphology antennal surface 62 species Scarabaeoidea using SEM microscopy, particularly also in light their evolution association angiosperms. We investigated correlation sensilla morphology, i.e., structure distribution, diversity lineage diversification rates. A high was observed but multiple transitional forms, even on same antennomere. interpreted as evidence for evolutionary plasticity. recognized clear patterns convergence repeated certain types placoid One main tendency found phytophagous Pleurostict chafers shift from trichodea to placoid-like sensilla, apparently enhanced by increase surface, either size or number lamellae. This trend occurred not only Pleurosticts, Glaphyridae, second angiosperm-associated Scarabaeoidea. However, our results suggest no direct relation between rate general origin could be explained species-poor lineages possessing otherwise successful rich groups having (e.g., dung beetles). Results further reveal need refine current phylogenetic hypotheses more comprehensive taxon sampling expand molecular characterization pheromones odor binding proteins better understand role chemical communication diversification.