Saturated hydrocarbons as kairomonal source for the egg parasitoid, Trichogramma chilonis Ishii (Hym., Trichogrammatidae)

Abstract

Studies on the effect of saturated hydrocarbons on parasitization by the egg parasitoid Trichogramma chilonis Ishii were carried out in the laboratory and net house. Bioassay of 11 hydrocarbons, viz. pentadecane, heptadecane, ecosane, heneicosane, docosane, tricosane, tetracosane, pentacosane, hexacosane, octacosane and hexatriacontane, were carried out under controlled conditions in the laboratory. These were also tested on potted maize plants in a net house. Among the saturated hydrocarbons, octacosane recorded the highest parasitoid activity index followed by docosane and tricosane. However, tricosane caused the highest percentage of parasitization, which was at par with octacosane and docosane. A positive correlation was found between concentration and kairomonal activity only in case of tricosane. In the net house, tricosane recorded the highest parasitization. Response of the parasitoid to egg cards treated with hydrocarbons decreased with increase in distance between the release point and host eggs. No parasitization was observed in host eggs placed at 8 m and 10 m away from the point of release except in the case of tricosane and pentacosane.

Kairomonal effect of some saturated hydrocarbons on the egg parasitoids, Trichogramma brasiliensis (Ashmead) and Trichogramma exiguum, Pinto, Platner and Oatman (Hym., Trichogrammatidae)

“…Pentadecane showed the highest PAI at C 2 whereas the highest parasitism was noted at C 5 . P admavathi and P aul (1998) reported that 125 ng/cm 2 concentration of tetracosane and 250 ng/cm 2 concentration of eicosane recorded the highest response of Trichogramma chilonis (Ishii) which corroborates the present finding in the case of T. exiguum . They also reported that 62.5 ng/cm 2 concentration of octacosane and docosane, 125 ng/cm 2 concentration of pentacosane and 250 ng/cm 2 concentration of heneicosane recorded the highest responses of T. chilonis , which differ from the present findings.…”

“…(1997), reported the highest parasitism by T. brasiliensis and Trichogramma japonicum (Ashmead) in the case of tricosane‐treated egg cards followed by pentacosane. P admavathi and P aul (1998) also reported tricosane to be the best hydrocarbon for attracting T. chilonis followed by octacosane and docosane. All these reports corroborate the present findings.…”

“…(1997) reported that heptadecane elicited lower responses from T. brasiliensis and T. japonicum . P admavathi and P aul (1998) reported heptadecane, eicosane, tetracosane and pentacosane to have poor kairomonal activity against T. chilonis .…”

Plant Volatile Chemicals and Insect Responses

“…Octacosane recorded the highest parasitoid activity index followed by docosane and tricosane. However, the tricosane caused the highest percentage of parasitisation, which was at par with octacosane and docosane (Padmavathi and Paul 1998 ). Similar studies with the maize weevil, Sitophilus zeamais , an economically important pest of stored grains in tropical and subtropical regions of the world, also demonstrated the role played by VOCs from the maize ( Zea mays ) plants in host location by this insect.…”

Chemical characterization of contact semiochemicals for host-recognition and host-acceptance by the specialist parasitoid Cotesia plutellae (Kurdjumov)

“…In social Hymenoptera, the cuticular lipids used in insect/insect relationships are mainly hydrocarbons and are involved in a variety of functions such as nest-mate recognition, reproduction, or parasitism (Dettner & Liepert 1994;Turillazzi et al 2000;Ruther et al 2002;Dani et al 2005). In parasitoid wasps, non-volatile host cuticular lipids are used in very short range and in specialist parasitoids serve as chemical recognition signals to identify host species (Vinson 1976;Rutledge 1996;Howard et al 1998;Padmavathi & Paul 1998;Kumazaki et al 2000) or to discriminate suitable individuals for oviposition (Vinson & Guillot 1972;Buckner & Jones 2005).…”