Red Imported Fire Ants: Effects of Insect Growth Regulators on Caste Formation and Colony Growth and Survival1

Abstract

Fourteen of 26 insect growth regulators (IGRs) administered in peanut butter bait to large laboratory colonies of Solenopsis invicta Buren caused a shift in caste differentiation with the result that worker brood production ceased and production of alate forms, most deformed wings, increased. Also, 8 of the compounds caused one or more colonies to die: AI3-36206 (1-(S-methoxy-4,8-dimethylnonyl)-4-(I-ethylethyl) benzene) caused 15 of 20 treated colonies to die; and A13-36093 (1-(8-ethoxy-4,8-dimethylnonyl)-4-(1-methylethyl) benzene) and AI3-35477 (JH-25) (E)-1-[(7-ethoxy-3,7-dimethyl-2-octenyl) oxy]-4-ethylbenzene or (E)-1-[ (7-eth-oxy-3,7-dimethyl-2-octenyl)oxy]-4-ethylbenzene) caused 3 of 4 and 6 of 9 colonies, respectively, to die.