Response of egg-pupal parasitoid Fopius arisanus (Sonan) to infochemicals from the host eggs' surface of Bactrocera dorsalis (Hendel)

Abstract

To determine host-related infochemicals that facilitate contact between the egg-pupal parasitoid, Fopius arisanus (Sonan), and its host, Bactrocera dorsalis (Hendel), we analyzed the volatiles on the surface of B. dorsalis eggs by hydrocarbon profiling of the hexane extracts using Gas Chromatography–Mass Spectrometry (GC–MS). These analyses resulted in the identification of 12 components from the egg surface. Among these 6 were alkanes (Dodecane, Heneicosane, Docosane, Tricosane, Tetracosane and Pentacosane) and the proportion was 42.79%, 1 was a fatty acid (Palmitic acid) and the proportion was 3.88%, 3 were fatty acid derivatives (Dodecanoic acid methylester, Lauric acid ethyl ester and Ethyl tetradecanoate) and the proportion was 45.92%, and 2 were alcohols (Tetradecanol and Hexadecanol) and the proportion was 7.41%. 9 chemicals were chosen from the above 12 components to study the EAG and behavioral responses of male and female F. arisanus. The results showed that the EAG and behavioral responses of F. arisanus to same chemical had similar trends, and both EAG relative values and lure rates of females were higher than males' generally. However, for Dodecane and Tetracosane the EAG relative values and lure rates showed extremely significant differences between males and females respectively, for Tricosane there was significant difference, for Ethyl tetradecanoate there was no significant difference between males and females of the relative EAG values but of the lure rates there was significant difference. The results maybe provide new insights from the chemical relationship between parasitoid and host to biocontrol B. dorsalis using F. arisanus.