Sex Pheromones in Insects

Rory Atteridge 0603612E Sex Pheromones in the Insects Introduction Sex pheromones are chemicals or odours given off by an individual in order to invoke a sexual response or behaviour change on individuals of the same species (Shorey 1973). These chemicals can be released by males and/or females, depending on the species (Gieselhardt et al. 2008, Ayasse et al. 2001). Pheromones generally consist of a carbon backbone of between 10 and 20 carbon atoms (in Lepidoptera), these are however arranged to form multitudes of different compounds, ranging from methyl groups and alcohols to fatty acids and acetates. These include isomers and stereoisomers of the same compounds allowing for a large diversity and chance for high species specificity (Raina 1993, Ayasse et al. 2001, Roelofs and Brown 1982, Lanier 1970). Sex pheromones have been studied in greater detail over recent years, but most historical work was done on Hymenoptera and Lepidopteran species. However, work has been done on Coleoptera, Dictyoptera and Mantodea(Perez 2005, Ayasse et al. 2001). Pheromones are released from many anatomical sites of the insect body. Some of the more obvious and common places include in pheromone glands between the 8th and 9th segments of the lepidopteran abdomen and the aedaegal glands of most insects (Gieselhardt et al. 2008, Roelofs and Brown 1982, Ayasse et al 2001). There are many other, more unexpected, locations at which pheromones are released or stored. These include the antennae of many parasitic wasps (Isidoro et al. 1996), the cuticle of insects in the form of lipids (Jurenka et al. 2007), venom glands of ants and mandibular glands of some flightless bees (Ayasse et al. 2001). Detection and tracking of pheromones Other location mechanisms include the orientation of an insect towards the source point of a pheromone. In the Desert Tenebrionid Beetle, once the male detects the sex pheromone of the female, he stops and walks in a circle in what seems to be

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