Appl. Entomol. Zool. 36 (3): 299–309 (2001)

Pheromone communication and mating behaviour of coffee white stem borer, quadripes Chevrolat (Coleoptera: Cerambycidae)

Marc Rhainds,* Chin Chiew Lan,1 Skip King, Regine Gries, Li Zhen Mo2 and Gerhard Gries Center for Environmental Biology, Department of Biological Sciences, Simon Fraser University, Burnaby, B.C., V5A 1S6, Canada 1 Nestlé R&D Center Sdn. Bhd., P.O. Box 185, 08000 Sg. Petani, Kedah D.A., Malaysia 2 Nestlé Agricultural Service Liaison Office, 19 Renmin Donglu, 650051 Kunming, Yunan, China (Received 10 July 2000; Accepted 16 February 2001)

Abstract This study investigated pheromone communication and mating behaviour of the coffee white stem borer (CWSB), Xy- lotrechus quadripes (Coleoptera: Cerambycidae), in South Yunan, China. Coupled gas chromatographic-electroan- tennographic detection (GC-EAD) and GC-mass spectrometric (MS) analyses of volatiles released by male and fe- male CWSB identified 2-hydroxy-3-decanone and 2,3-decanedione as male-specific candidate pheromones. Further GC-EAD and GC-MS analyses confirmed that only (S)-2-hydroxy-3-decanone is produced by male CWSB and elicits antennal responses by male and female CWSB. In field experiments, 2-hydroxy-3-decanone as a trap bait afforded capture of one female CWSB, and in laboratory experiments it weakly attracted female but not male CWSB. Complex mating behaviour in CWSB includes: 1) attraction of potential mates by both sexes; 2) repeated landings (with ever decreasing distance) of a female next to a male; 3) males dashing to a nearby female; 4) rejection of mating attempts by females; 5) post-mating female guarding by males; and 6) size-dependent mating success of males. Considering this complex mating behaviour, lack of direct flight towards pheromone sources, mating near pheromone-baited traps, and only moderate attractiveness of (synthetic) pheromone, pheromone-based trapping of females does not seem to be a viable strategy for managing CWSB populations in China.

Key words: Xylotrechus quadripes, coffee white stem borer, Cerambycidae, pheromone, mating behaviour

Male CWSB from India produce (S)-2-hydroxy- INTRODUCTION 3-decanone as a female attracting pheromone (Hall The coffee white stem borer (CWSB), Xy- et al., 1998). This study was undertaken to investi- lotrechus quadripes (Chevrolat) (Coleoptera: Cer- gate pheromone communication and mating behav- ambicydae), is a major pest in commercial coffee iour of CWSB in South Yunan, China. Specific ob- plantations in Asia (Duffy, 1968; Visitpanich, jectives were to: 1) identify pheromone compo- 1992a; Kuang et al., 1997; Rhainds et al., 2001a). nents; 2) evaluate behavioural activity of candidate Damage inflicted to coffee stems by wood-feeding pheromones; 3) document pre-mating interactions larvae causes mortality of plants or reduction in between adults; and 4) quantify intraspecific varia- fruit production (Veeresh, n.d.). Because larvae in- tions of mating success. side coffee stems are difficult to control, manage- ment strategies are aimed at preventing infestation, MATERIALS AND METHODS either by manually collecting adults, uprooting infested stems, or interfering with oviposition Identification of candidate pheromone. Three behaviour by scrubbing stems or swabbing them shipments of adult CWSB were sent from South with repellent chemicals (Veeresh, n.d.). Recently, Yunan to Simon Fraser University. Volatiles re- pheromone-based monitoring and/or mass trapping leased by males or females (Visitpanich, 1994) of CWSB populations have been considered as po- were captured in 6 separate aerations. Groups of tential management tactics. 15, 21 or 25 males, and of 12, 22 or 36 females,

* To whom correspondence should be addressed at: Department of Entomology, New York State Agricultural Experiment Station, Cornell Univer- sity, Geneva, NY 14456, U.S.A.

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