Production and Flight of Alate Red Imported Fire Ants12

Abstract

Emergence of alate Solenopsis invicta Buren from several habitats in northern Florida averaged 187,000/acre/year. The number of active mounds per acre varied between habitats, and the numbers of alates produced was not directly correlated with the numbers of mounds per acre. Alates were captured each month, with the heaviest flights occurring April through August. Of the alates captured, 52% were females. Some habitats produced a higher male:female sex ratio than others. About 90% of the flights were composed of over 74% of one sex of alates; 65% of the flights were monosexual. Rainfall stimulated flights, but high relative humidity did not. Some flights continued for 2–3 days after a rain. Colonies sometimes had more than one mound, and flight could occur from either or both mounds. Artificially created air movement terminated flights, but shading did not. Two ovipositing queens were found in a single colony. Sexual brood appeared in mounds in March, and first flights composed of alates which developed from the new season's brood occurred in late April and early May. Dealate and deformed sexual forms which had been carried over the winter were seen attempting to fly in the spring.