Mate Recognition by the Green Mate Borer, Hedypathes betulinus (Coleoptera: Cerambycidae): the Role of Cuticular Compounds

Abstract

Green mate, Ilex paraguariensis (Aquifoliaceae), is native to South America and its range includes the south of Brazil. Hedypathes betulinus (Coleoptera: Cerambycidae) is considered the most important insect pest of green mate, causing severe damage to plants and significant economic losses. In previous work, laboratory assays were performed to document the mating sequence of this species and the male long-range sex pheromone was identified. Previous reports of the mating sequence suggested that males recognize females only after antennal contact and consequently the existence of a contact sex pheromone. To test the hypothesis that mate-recognition in H. betulinus is mediated by a contact sex pheromone, this study analyzed male and female body extracts by GC-MS. Extracts were fractionated to separate the compounds by polarity, producing hexane, cyclohexene and ether fractions. Active fractions were identified with laboratory bioassays. Bioassays were performed by introducing female cadavers to live males and male copulation response scored (± ). In assays using solvent washed female cadavers, males did not recognize female cadavers, but attempted copulation with female cadavers with the extract re-applied. Cumulatively, these results suggest that a contact sex pheromone on the cuticle of females mediates mate recognition. Laboratory bioassays and analysis of the female solvent extracts produced by fractionation, individually and in binary and ternary combinations, suggests that the more polar compounds present in the ether fraction are crucial to mate recognition in this species.