Contact chemoreceptive mate recognition in Cerambyx welensii Küster (Coleoptera: Cerambycidae)

Abstract

Cerambyx welensii Küster (Coleoptera: Cerambycidae) is a wood‐borer responsible for the decline of Mediterranean oaks in open woodlands. To establish that contact pheromones are involved in mate recognition of C. welensii, we extracted the cuticular hydrocarbons by solid phase microextraction at pre‐reproductive, beginning and ending of the reproductive period, and by solvent extraction of prothorax and elytra. The extracts were analysed by GC–MS under electron impact and chemical ionization conditions. Cuticular hydrocarbon profiles varied according to the reproductive period, although differences between sexes were not significant. Two compounds, 11/13‐methylheptacosane and 11‐methylnonacosane were more abundant in females at the beginning and ending of the reproductive periods. Compound 11/13‐methylheptacosane was also more representative in female prothorax than in males, and 2‐methyloctacosane was richer in male elytra than in females. We also studied the role of cuticular hydrocarbons in mate recognition in arena bioassays. Treatment of solvent‐washed dead females and glass dummies with one female equivalent (FE) of cuticular extract elicited mating responses in males, especially at the beginning of the reproductive period, with copulation attempts reaching 61.9% on solvent‐washed dead females and 23.8% on dummies. The successive treatment with synthetic compounds approaching a male cuticular profile inhibited male response. Our results confirm that contact pheromones mediate mate recognition in C. welensii. Knowledge of the precise role played by the major compounds 11/13‐methylheptacosane and 11‐methylnonacosane and other minor compounds representative in female prothorax may contribute to the development of novel management strategies against C. welensii.

Evidence of a pheromone involved in the behaviour of Drosophila suzukii Matsumura (Diptera: Drosophilidae)

“…On the other hand, Sánchez‐Ororio et al. (2023), when evaluating the effect of contact pheromones involved in mate recognition in Cerambyx welensii , found a higher abundance of nine compounds in males than in females, including heneicosane, hexacosane and pentacosane, which were also found in our GC–MS analysis. Heneicosane and hexacosane were also found in higher abundance in males than in females, while pentacosane was only found in males.…”

Female delayed mating has a limited impact on the reproductive output of Cerambyx welensii, a synovigenic longhorn beetle

“…Females also have contact pheromones in the cuticular wax layer that trigger a rapid male response at close range (Sánchez-Osorio et al, 2023). Females walking on the host tree may deposit contact pheromones leaving a chemical trail that directs searching males towards them (Hanks & Wang, 2017).…”