Spinosad resistance affects biological parameters of Musca domestica Linnaeus

Abstract

Musca domestica is one of the major cosmopolitan insect pests of public health importance. Spinosad is considered an eco-friendly insecticide used for the management of M. domestica and other pests of significant concern. Cases of resistance against spinosad in M. domestica have been reported from some parts of the world; however, there are no reports of any negative effects of spinosad resistance on the fitness/biological parameters of M. domestica. To investigate fitness costs, a near isogenic M. domestica resistant strain (Spin-R) was constructed using Spin-UNSEL-susceptible and Spin-SEL-resistant strains sharing a close genetic background. We found significantly reduced rates of adult eclosion, fecundity, egg hatching, survival, and lengthened developmental time in the Spin-R strain. Moreover, the values of different fitness parameters like biotic potential, mean relative growth rate, intrinsic rate of natural increase, and net reproductive rate, were also significantly reduced in the Spin-R strain, which reflect fitness costs most probably linked with spinosad resistance. The presence of fitness costs suggests likely instability of resistance to spinosad in M. domestica, which can be reverted by relaxing spinosad selection pressure and rotation with alternate insecticides. The wise use of insecticides will ultimately help to manage resistance in this pest and minimize environmental pollution.

Characterization of permethrin resistance in a Musca domestica strain: resistance development, cross‐resistance potential and realized heritability

“…Previously, cross‐resistance to cypermethrin, deltamethrin and β‐cyfluthrin in a permethrin selected strain of M. domestica was reported by Liu and Yue . Being in different pesticide classes, cross‐resistance of the Perm‐SEL strain with imidacloprid (neonicotinoid class) or spinosad (spinosyns class) was not expected . Absence or lack of cross‐resistance to imidacloprid and spinosad provides an opportunity to use them as alternative insecticides in the resistance management program.…”

Toxicity of Different Dilutions of Spinosad Bait against Two Fruit-fly Species (Diptera: Tephritidae)

“…The medfly insects used in the present experiment were from a pesticide-susceptible population (S) (personal communication); thus, the formulated spinosad (Success ® 0.02 CB) at high insecticide concentrations may not have provided the appropriate feeding stimuli to induce the fruit-fly (C. capitata and A. grandis) insects to ingest enough toxic ingredient to cause mortality, considering the non-increasing mortality rates with the concentration increase in the toxic bait, mainly for the three lowest spinosad dilutions at 240 minutes after treatment (Table 2). This hypothesis should be elucidated in future studies because this effect on the medfly behaviour can favour the development of insecticide resistance, changes in biological parameters or induce population outbreaks [32,33,34], especially if bait stations are established in wide-area programmes. In this aspect, the amount of food ingested by Anastrepha suspensa (Loew) was dependent on the concentration and class of the food (carbohydrate, protein, amino acid).…”

Permethrin resistance associated with inherited genes in a near‐isogenic line of Musca domestica

“…The Perm‐SEL strain had almost 600‐fold resistance to permethrin in comparison with the Lab‐susceptible strain 29 . Both strains were used to construct a near‐isogenic line (Perm‐R) with permethrin resistance following the backcrossing methodology of Khan 30 and Mu et al 31 with modification.

Mass mating was done by introducing 50 pairs of Lab‐susceptible females and Perm‐SEL males into a mesh cage within 6 h of adults' eclosion. A self‐cross between the offspring of Lab‐susceptible and Perm‐SEL strain yielded offspring designated as the F1 progeny.

…”

“…The selection bioassays and backcrossing were completed when the LD 50 values of the self‐bred progenies BCnF2, BCnF3 and BCnF4 had become stable. All strains were maintained under laboratory conditions as described previously 17,30 All strains were reared under the laboratory conditions [25 ± 2 °C, 65 ± 5% relative humidity (RH), 12:12 h light/dark photoperiod] and fed with sugar–milk‐based diet as described previously 17 .…”