Unraveling the function of the hooked hairs of females of Monoeca species (Apidae: Tapinotaspidini)

Abstract

Females of all Monoeca species have strong hooked bristles on the mesosomal venter, leg bases, and metasomal sterna (2–4), which suggests that they could be related to pollen collection; however, this has not been proved. These females show a strong association with species of Malpighiaceae that provide sources of oil and pollen. To prevent/reduce spontaneous self-pollination, most Neotropical Malpighiaceae species have a stigmatic cuticle that prevents the germination of self-pollen grains while intact. We performed field observations and offered virgin flowers to Monoeca females. Our results show that the hooked hairs of Monoeca species collaborate in the pollen collection from the anthers and could break the stigmatic cuticles during their stereotyped oil-collecting behavior.