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

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.

Chemical screening, insecticidal and reprotoxic activities of Tecoma stans ethanolic leaf extract against the vector mosquito Culex pipiens

“…The scale of this situation emphasizes the insufficiency of the current approaches, and new further inroads must be involved to switch from chemical‐based insecticides to non‐conventional control methods. To achieve the expected objectives, various intervention policies and strategies are based on integrated measures such as insect growth disruptors (Hamaidia et al, 2018; Hamaidia & Soltani, 2014; Hamaidia & Soltani, 2016; Hamaidia & Soltani, 2019, 2020) or biopesticides (Bouguerra et al, 2018; Bouzidi et al, 2020; Draouet et al, 2020; Dris et al, 2017).…”

The Behavioral Toxicity of Insect Growth Disruptors on Apis mellifera Queen Care

“…One of the most ubiquitous classes of agrochemicals honey bees can encounter are insect growth disruptors (IGDs) (Traynor et al, 2016;Fine and Corby-Harris, 2021), which are commonly applied in blooming almond orchards (CalDPR, 2019;Wade et al, 2019). IGDs are agrochemical pesticides that target pathways associated with insect growth and development (Pener and Dhadialla, 2012), though they are also known to impact numerous aspects of adult insect behavior including oviposition (Smagghe and Degheele, 1994;Hamaidia and Soltani, 2021), mating (Thompson et al, 2005), memory and learning (Abramson et al, 2004), and behavioral maturation (Jaycox et al, 1974;Robinson, 1985). Because IGDs exhibit low lethality to adult honey bees (Tasei, 2001), they are often applied to blooming crops where bees forage, such as almonds (Mullin et al, 2016;Wade et al, 2019;CalPIP Home -California Pesticide Information Portal).…”