When a male perceives a female: the effect of waxy components on the body surface on decision-making in the invasive pest weevil.

Mutsumi Isa,Norikuni Kumano,Haruki Tatsuta

doi:10.1098/rsos.181542

Abstract

Insects use various semiochemicals for sexual communication and mate recognition; these can therefore be used to govern the behaviours of harmful pest species, and several candidate chemicals have been explored for this purpose. For the West Indian sweet potato weevil, Euscepes postfasciatus, which is one of the most serious pests of sweet potato, no effective capture techniques, such as sex pheromone lures, exist. Toward exploring promising procedures for monitoring these weevils, we assessed the effect of secretions on the body surface on the recognition of congeners and on courtship behaviour in the weevils. Our study clearly demonstrated that weevils responded to extracts from the body surface, and the behaviour adopted by the weevils varied significantly depending on the condition of the extracts. Furthermore, we found a significantly prolonged retention time for males on glass beads covered with extracts of females based on survival analysis. These findings are, as far as we are aware, the first to show the effect of lipid components of the body surface on decision-making in these economically important pest weevils.

Highlights

Considerable ecological, behavioural and physiological information regarding the hydrocarbons on the body surfaces of insects has recently been accumulated (e.g. [1])
We used a strain of E. postfasciatus originally captured at Yomitan village (268240 N, 1278430 E) in May 2006 and maintained at 25 + 18C under a photoperiod of 14 L : 10 D at a facility of the Okinawa Prefectural Plant Protection Center (OPPPC), Japan
The examination of the composition of chemicals in the extract from the cuticular surface was not the prime focus in the present study, our behavioural experiment using weevil extracts clearly showed that male weevils paid attention to glass beads coated with dissolved compounds and their pre-copulatory behaviour was triggered, suggesting that the males of E. postfasciatus perceived some stimulus signals retained on the body surface

Summary

Introduction

Considerable ecological, behavioural and physiological information regarding the hydrocarbons on the body surfaces of insects has recently been accumulated (e.g. [1]). [2] and function to prevent water loss and desiccation [3] and infection by microorganisms [1], and 2 are used for mutual communication in individuals belonging to different sexes in a great variety of insects [4,5]. They are known to be semiochemicals that play various crucial roles, such as providing information regarding the socio-sexual status of males, as well as species and gender recognition [1,6,7]. From the view of practical use in pest management, such semiochemicals, as well as volatile sex pheromones, can be used for the orientation and trapping of harmful insect pests (e.g. [11,12])

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