Mating Flight Activity as Dealation Factors for Red Imported Fire Ant (Hymenoptera: Formicidae) Female Alates

Abstract

Queens of the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), release a primer pheromone that inhibits dealation (wing removal) of nestmate female alates by presumably suppressing endogenous concentrations of juvenile hormone (JH). Alates cast their wings once separated from the queen; however, the point of initiating dealation varies upon conditions. Alates are stimulated to shed their wings after several days of the death or removal of the queen, whereas newly mated alates dealate within 1 h after the mating flight. We found no single premating behavior or combination of behaviors associated with the nuptial flight that induces dealation rates comparable with that of newly mated queens. Copulation by itself or in conjunction with other behavioral signals and environmental prompts seems to be critical in causing rapid dealation in newly inseminated alates. In addition, colonies containing alates treated with precosene would not initiate mating flights nor could they be induced to fly. We suggest that precosene treatment affects the corpora allata (CA), but CA products other than juvenile hormone (JH) or in combination with JH are responsible for rapid dealation after mating. Dealation in the two contexts, within the colony and after mating flights, seems to occur via separate mechanisms.