ATTRACTION OF THE SEXES IN FORMICA-LUGUBRIS ZETT (HYMENOPTERA, FORMICIDAE)

Sexuals of Formica lugubris fly to mating places, where females attrac t males by using a sex pheromone. Females collected on the nest surfac e before departing on a mating flight are much less attractive than th ose collected on the mating place after the mating flight, suggesting that the mating flight triggers the release of the sex pheromone. Olfa ctory cues are essential for males to locate females while they patrol . Males probably use visual cues to locate females once they have alig hted nearby them. Males are also attracted by aggregations of other ma les on the ground, probably because one or several females are likely to be close to male aggregations.