Morphology of putative female sex pheromone glands and mating behaviour in Aphidoletes aphidimyza

Adult emergence period, sex ratio, female calling behaviour, and the risky mating behaviour of A. aphidimyza in spider webs are described. We provide evidence that A. aphidimyza females produce a sex pheromone and attract males, and we give a description of the location and structure of the supposed pheromone producing glands of A. aphidimyza based on scanning and transmission electron microscopy. This is the first demonstration of occurrence of sex pheromones for a zoophagous species of Cecidomyiidae. The question is discussed why A. aphidimyza is using spider webs for mating.