Fitness costs associated with chlorantraniliprole resistance in Spodoptera exigua (Lepidoptera: Noctuidae)

Abstract

BACKGROUND The field population of Spodoptera exigua, an intermittently occurring polyphagous pest, has developed resistance to chlorantraniliprole, while whether or not such resistance carries fitness costs remains poorly understood. Here we selected six generations of the Leshan population (LS‐P) by two‐way selecting method, and obtained a highly resistant strain (CH‐RE) and resistant degeneration strain (CH‐SE) sharing a similar genetic background. After that fitness costs were evaluated by comparing the life history characteristics of CH‐RE, CH‐SE and the laboratory susceptible strain (SE‐Lab) via the age‐stage two‐sex life table method. RESULTS The resistance ratio of CH‐RE and CH‐SE were 226.69‐fold and 3.72‐fold, respectively, and the estimated realized heritability (h2) of CH‐RE was 0.058. Compared with CH‐SE, the duration of pre‐adult, the longevity of adult, adult preoviposition period (APOP) and average generation time (T) of CH‐RE had significantly increased, but the oviposition days, average fecundity, intrinsic growth rate (r), weekly growth rate (λ) and reproductive rate (R0) decreased significantly. Moreover, the relative fitness of CH‐RE was 0.25, and showed fitness costs. Concurrently, the fecundity of CH‐SE was slightly lower than SE‐Lab, but there was no significant difference in r, λ and R0, and the fitness (1) of CH‐SE was similar to SE‐Lab (1.02), which was no fitness cost. CONCLUSION These findings represent that chlorantraniliprole resistance in S. exigua has a fitness cost, and the fitness cost will disappear with the recovery of sensitivity when the insecticide is stopped for field populations, supporting that such resistance would be managed by switching off the selection pressure with rotation with alternate insecticides. © 2020 Society of Chemical Industry

Resistance of Nilaparvata lugens (Hemiptera: Delphacidae) to triflumezopyrim: inheritance and fitness costs

“…In the sulfoxaflor-resistant N. lugens strain, the pre-adult period and TPOP were significantly prolonged, but the female adult period, oviposition days, total fecundity and egg hatchability were markedly reduced. 24 Deleterious impacts of insecticide resistance on fitness have also been reported in other resistant insect populations, including those of Diaphornia citri, 48 Aphis gossypii, 26 Spodoptera exigua 27 and Helicoverpa armigera. 49 Furthermore, studies have proposed that the frequency of resistance alleles might decrease when the selection pressure of insecticides is removed.…”

“…49 Furthermore, studies have proposed that the frequency of resistance alleles might decrease when the selection pressure of insecticides is removed. 27,50 Therefore, negative fitness cost may lead to rapid recovery of sensitivity of the TR population in the insecticide-free environment, 25,28 and triflumezopyrim can be alternated with insecticides having different modes of action and without cross-resistance to maintain its efficacy. In short, the TR strain of N. lugens showed a lower fitness than the TS strain, pointing towards the possible delay in development of triflumezopyrim resistance and favoring its long-term usage in the field.…”

“…25,26 Fitness costs are not only important factors influencing the evolution of insecticide resistance but are also the basis of pest resistance management. 27 The reduced fitness of resistant insect populations mainly results from the presence of resistance alleles in resistant insect populations. 28 Previously, fitness costs linked with the resistance of N. lugens to clothianidin, sulfoxaflor, imidacloprid, nitenpyram, chlorpyrifos and fipronil have been reported, and adverse impacts on the life history traits of these resistant strains were observed.…”

Fitness cost of spinosad resistance related to vitellogenin in Frankliniella occidentalis (Pergande)

“…Fitness costs, defined as trade‐offs between two or more traits in which alleles that increase fitness in one environment reduce fitness in another, have been associated with insecticide resistance and found to delay the development of such resistance 5,6 . In the absence of the insecticide, fitness costs associated with resistance to that insecticide can result in lower fecundity, delayed maturation, longer developmental time and reduced longevity of the resistant genotype relative to the nonresistant genotype 7–9 . Studies of fitness costs attributed to spinosad resistance have been reported previously for Plutella xylostella , 10 Helicoverpa armigera , 11 Bactrocera dorsalis , 12 Spodoptera litura , 13 Spodoptera frugiperda 14 and Ceratitis capitata , 15 all of which led to the extension of development duration, the decline of survival rate and the decrease of fecundity.…”

New Insights into the Life History Changes Can Enhance Control Strategies for Therioaphis trifolii

“…Life-table analysis has emerged as a powerful tool for analyzing and understanding the effects of abiotic and biotic factors such as temperature on insect growth, survival, reproduction, and population growth [26][27][28]. This analysis is the key to population ecology [29], pest biological control [30], host preferences [25,31,32], and the adaptation of insects [28,33].…”