A Male Aggregation Pheromone in the Bronze Bug, Thaumastocoris peregrinus (Thaumastocoridae)

Abstract

Forest plantations in Uruguay have doubled in the past decade, with Eucalyptus spp. leading this growth. The bronze bug, Thaumastocoris peregrinus (Heteroptera: Thaumastocoridae), originally restricted to Australia, is an important emerging pest of Eucalyptus plantations in the Southern hemisphere. T. peregrinus feeds on mature Eucalyptus leaves, causing them to turn brown and often fall from the tree. Although population dynamics and behavioural patterns are not clearly understood, circumstantial observations suggest that males and nymphs aggregate. We used gas chromatography coupled to mass spectrometry to analyze volatile organic compounds emitted by virgin males and females, and characterized a male-specific compound, 3-methylbut-2-enyl butanoate, based on mass spectral data and chromatographic comparison with a synthetic standard. We also performed Y-olfactometer bioassays to test the attraction of virgin males and females toward live virgin males, male volatile extracts, and synthetic 3-methylbut-2-enyl butanoate. Males were attracted toward conspecific males, while virgin females showed no preference, suggesting that male volatiles are not involved in sexual communication. Further olfactometer tests showed that males were attracted to male volatile extracts and to synthetic 3-methylbut-2-enyl butanoate. The ecological significance of this compound and its potential use for the management of T. peregrinus in Eucalyptus forests will be further investigated.