Methoxyfenozide, a Molting Hormone Agonist, Affects Autogeny Capacity, Oviposition, Fecundity, and Fertility in Culex pipiens (Diptera: Culicidae)

Abstract

Abstract The current study aimed to evaluate the effects of methoxyfenozide (RH-2485), an insect growth disrupter (IGD) belonging to molting hormone agonist class, against female adults of Culex pipiens L. under laboratory conditions. Lethal concentrations (LC50 = 24.54 µg/liter and LC90 = 70.79 µg/liter), previously determined against fourth instar larvae, were tested for adult female fertility, fecundity and oviposition after tarsal contact before mating and any bloodmeal. Methoxyfenozide was found to alter negatively their autogeny capacity and oviposition. A strong reduction of 56% and 72% (P < 0.001) in females’ autogeny capacity was observed in both treated series, respectively. Alteration in oviposition were found to be higher with LC90 (OAI-LC90 = −0.62) than with the LC50 (OAI-LC50 = −0.42). Also fecundity and hatching rate (fertility) were significantly reduced in treated series as compared to controls. A significant reduction of 37.65 and 28.23% in fecundity and decrease of 56.85 and 71.87% in fertility were found, respectively in LC50 and LC90 treated series. Obtained data clearly demonstrated that methoxyfenozide have significant depressive effect on reproductive potential against medically important vector with minimizing ecotoxicological risks in mosquitoes management.