Symposium on reproduction of arthropods of medical and veterinary importance. II. Meeting of the sexes.

Abstract

Many parasitic species intimately associated with their hosts mate in the burrow, lair or rookery of the host, or on the host. Other species meet and mate on or near free-roaming hosts which they have sought out for feeding, oviposition or larviposition, whereas some blow fly and flesh fly species mate near dead “hosts” on which eggs or larvae are deposited. Another common method of encounter is meeting at a specific topographic site attractive to both sexes (e.g., a hilltop, stream or trail). Some species meet at emergence sites. In species of Diptera which aggregate at specific sites, males swarm or hover over a distinctively recognizable landmark or perch on or adjacent to the landmark. Males wait for females at aggregation sites for about 30 min. to several hours each day; females generally are present at such sites only as long as it takes to copulate. Pursuit by a male and subsequent coupling occurs after a female enters a male swarm or flies over a perched male. The opposite sex is accepted or rejected, within centimeters, on the basis of chemical, acoustic, visual or tactile stimuli. Sex pheromones or assembling scents have now been associated with several species of medical-veterinary importance, but these chemicals do not appear to attract from long distances. They seem more important as a means of contact recognition of the sexes after they have met. Females of most species mate only once, with members of the Nematocera and Brachycera normally mating before seeking a blood meal. Females of most Cyclorrapha, and many arthropods other than Diptera, feed on protein before mating.