Effects of photoperiod and mating on sex pheromone production and release by oviparae of the aphid Schizaphis graminum

Abstract

ABSTRACT. By extraction and bioassay procedures, it is shown that the sex pheromone released by oviparae of the greenbug, Schizaphis graminum (Rondani), during the daylight hours of a light: dark regime, is present in the tibia of the metathoracic legs only during daily photophases.Shortly after mating, pheromone‐emitting oviparae cease to produce as well as to release the pheromone. This mating‐induced response requires that copulation be completed, and suggests the involvement of sperm or seminal substances transferred by the males to the oviparae during copulation.Although multiple matings increase the number of eggs deposited by an ovipara, the mating‐induced termination of pheromone production/ release would enhance the chances for mating of neighbouring oviparae. This would result in a further increase in egg production as well as in the number of genetically similar offspring, because neighbouring oviparae are most probably sisters. The phenomenon is discussed in terms of kin selection.