Green traps and (Z)-3-hexenol as novel attractive cues for males Coraebus undatus

Abstract

Monitoring and mass trapping are two relevant strategies within the Integrated Pest Management principles. However, the development of an effective trapping method represents a challenge in which multimodal cues should be taken into account to ensure trapping performance. In the case of the flathead oak borer, Coraebus undatus (F.) (Coleoptera: Buprestidae), trapping methods so far mainly rely on sticky or interception purple traps that appear attractive for mated females when placed in the understory. Taking into account the visual behaviour of the species and the kairomone activity of the green leaf volatile compound ( Z )-3-hexenol in other Buprestidae, we aimed to test the efficacy of green-coloured traps and ( Z )-3-hexenol as lures when placed in the canopy. We first examined the electroantennographic and behavioural response of both sexes to ( Z )-3-hexenol, and then evaluated the performance of the combination of unbaited canopy-placed sticky green prism traps or baited with ( Z )-3-hexenol. Antennae from virgin adults responded to increasing stimuli of ( Z )-3-hexenol following a dose–response pattern, although males exhibited a higher response than females overall. In olfactometric trials, ( Z )-3-hexenol evoked a positive chemotactic response in males and females. Sticky green prism traps in the canopy were attractive to males, and this attractiveness was significantly increased when releasing ( Z )-3-hexenol. Females were also attracted to green traps, although no significant effect of ( Z )-3-hexenol was reported. This study highlights the relevance of combining visual and chemical stimuli for efficiently trapping of C. undatus , especially males, representing a key step for better monitoring strategies of the species.

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