Sublethal Pyrethroid Insecticide Exposure Carries Positive Fitness Effects Over Generations in a Pest Insect

Abstract

Stress tolerance and adaptation to stress are known to facilitate species invasions. Many invasive species are also pests and insecticides are used to control them, which could shape their overall tolerance to stress. It is well-known that heavy insecticide usage leads to selection of resistant genotypes but less is known about potential effects of mild sublethal insecticide usage. We studied whether stressful, sublethal pyrethroid insecticide exposure has within-generational and/or maternal transgenerational effects on fitness-related traits in the Colorado potato beetle ( Leptinotarsa decemlineata ) and whether maternal insecticide exposure affects insecticide tolerance of offspring. Sublethal insecticide stress exposure had positive within-and transgenerational effects. Insecticide-stressed larvae had higher adult survival and higher adult body mass than those not exposed to stress. Furthermore, offspring whose mothers were exposed to insecticide stress had higher larval and pupal survival and were heavier as adults (only females) than those descending from control mothers. Maternal insecticide stress did not explain differences in lipid content of the offspring. To conclude, stressful insecticide exposure has positive transgenerational fitness effects in the offspring. Therefore, unsuccessful insecticide control of invasive pest species may lead to undesired side effects since survival and higher body mass are known to facilitate population growth and invasion success.

Contrasting susceptibility of lepidopteran pests to diamide and pyrethroid insecticides in a region of overwintering and migratory intersection

“…1). These low resistance ratio values for bifenthrin are similar to those for other U.S. cotton bollworm populations tested recently 30,44,45 or over 20 years ago, [46][47][48][49][50] likely caused by increased detoxification. This similarity among populations may be associated with the high dispersal capacity and reproductive biology of cotton bollworm, leading to extensive gene flow.…”

The impact of sublethal permethrin exposure on susceptible and resistant genotypes of the urban disease vector Aedes aegypti

“…aegypti tend to be conducted on susceptible insects and focus on a very small number of traits. 10,[21][22][23]33 Given the ubiquity of pyrethroid resistance in Ae. aegypti populations around the globe, this limits our ability to understand the impacts of sublethal exposure in the field and the extent to which they will favour further selection for resistance in Ae.…”

Predicting low-concentration effects of pesticides

“…We also assume that compensation of toxicant stress increases the survival rate of individuals and their offspring. This was often observed for different groups including aquatic 13 and terrestrial insects 14 , and crustaceans 15 . However, the increasing mortality under control conditions, without toxicant stress, indicates the presence of a previously unknown but significant presence of stress from a different source.…”