Interactions between male moths of the lightbrown apple moth, Epiphyas postvittana (Walker) (Lep.: Tort.), landing on synthetic sex pheromone sources in a wind-tunnel

Abstract. This study was designed to determine whether landings of males of Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae) on synthetic sex pheromone sources are influenced by other males which have preceded them in flying to and landing on the sources. The investigation comprised two separate experiments. In one, using a single pheromone source, insects released singly were compared with insects released in groups of three, and in the other, insects released in groups of five were presented with a choice between two identical sources. The resolution for changes in attractancy was higher in the choice experiment which demonstrated an increase in attraction for a source on which males had already landed and remained whilst the new male flew towards it. A single resident insect increased the source attractancy by a factor of 1.40 and a pair of insects by 1.77 compared with an empty source. With the single sources the data exhibited the same trend but the result was rendered not significant by an insufficient amount of data, although approximately equal times were allocated to each experiment. To achieve a significant result with the single sources at least 6 times as much data would need to be collected.