MALE PATROLLING BEHAVIOUR AND SEX ATTRACTION IN ANTS OF GENUS FORMICA

Patrolling behaviour, an adaptation bringing the sexes together for copulation, is defined as the flight movements of male ants as they leave their nests in search of reproductive females, and involves flight across wind until perceiving the presence of a female. Once sex attraction has occurred, males fly directly upwind to the general location of the female, and make rapid flitting and crawling movements up and down plant stems until contact is made with the female. This phenomenon has been observed of F. montana and F. pergandei and may be common to other species of Formica, even other genera of ants. The most plausible explanation of this attraction is that the males are responding to a pheromone released by a female. The attractant is apparently wind-borne, and males are able to determine the direction of its source by antennal movements. The immediate vicinity of a female may become so saturated with attractant that males are unable to find her directly, either by chemical or visual means, but must explore each specific area of vegetation until physical contact between them is made. Male attraction may be illustrative of the mechanism used by males of many ant species to locate mates during nuptial flights. In the absence of specialized mating aggregations such as swarms, an odour stimulus would probably be a more effective attractant than auditory or visual stimulation. That this mechanism may be used by other species of ants is suggested by the discovery that females of F. ulkei, which are reproductively unattractive on the vegetation surrounding a nest, later became attractive after flying a short distance and landing in a tree. © 1969.