Swarming and Mating Behavior of Laboratory and Field Strains of Culex tarsalis (Diptera: Culicidae)

Abstract

Swarming and mating behavior of a laboratory colony and adults emerging from field-collected immatures of Culex tarsalis Coquillett were observed in small laboratory and large outdoor cages. Natural populations were observed in foothill environments near Bakersfield (Kern County), Calif. Pairing and increases in percent of insemination occurred concurrently with swarming at dusk and to a lesser extent at dawn. Female presence was not essential to stimulate male swarming. Timing of movement to and from resting sites, swarming, and mating was similar among laboratory and field populations in the field, in outdoor cages, and in the laboratory. However, proportionately more laboratory males participated in crepuscular swarms in the outdoor cages. Correspondingly, the insemination of concurrently released females occurred more rapidly for laboratory than for field strains. Thus, colonization selected for demes able to swarm and mate in confined spaces.