Effects of semiochemical pre-feeding, physiological state, and weather on the response of Bactrocera dorsalis to methyl eugenol baited traps

Abstract

Plant-derived phenylpropanoids are semiochemicals that are often highly attractive to Bactrocera (Diptera: Tephritidae) males. One of these semiochemicals, methyl eugenol (ME), is used in the male annihilation technique (MAT) for the management of B. dorsalis (Hendel), a destructive horticultural pest. It is not normally viable to simultaneously implement MAT with the sterile insect technique (SIT), as released sterile males are attracted to MAT devices. However, prior semiochemical exposure can reduce the later response of Bactrocera males to the same or another semiochemical, which may allow the synchronous application of MAT and SIT. We determined how the interaction between semiochemical pre-feeding, weather, and fly physiology impacted the response of male B. dorsalis to ME baited traps. Response by a known number of males in field cages was determined in relation to temperature, relative humidity, semiochemical pre-feeding (ME, eugenol, or none), diet (protein supplemented and protein deprived) and age (4, 10 and 20 days old). Semiochemical pre-feeding of both ME and eugenol equally decreased the response of males that were 10 days old, or older, to ME baited traps. Adult diet had no effect on the response of males to ME baited traps. Response improved as temperature and relative humidity increased. These results highlight the feasibility of synchronous MAT-SIT programmes targeting B. dorsalis and the viability of continued protein supplementation of sterile males. We show that eugenol is an alternative to ME for suppression of male B. dorsalis response to MAT devices and that weather conditions significantly affect the variability and reliability of abundance estimates from trap captures.