Premium
Restoration of susceptibility following removal of selection for Cry34 / 35Ab1 resistance documents fitness costs in resistant population of western corn rootworm, Diabrotica virgifera virgifera
Author(s) -
Paddock Kyle J,
Hibbard Bruce E,
Barry Julie,
Sethi Amit,
Mueller Ashley L,
Shelby Kent S,
Pereira Adriano E
Publication year - 2021
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/ps.6266
Subject(s) - western corn rootworm , biology , bacillus thuringiensis , pest analysis , fecundity , population , larva , agronomy , selection (genetic algorithm) , seedling , sowing , botany , bacteria , genetics , demography , artificial intelligence , sociology , computer science
BACKGROUND Management of the corn pest, western corn rootworm (WCR), Diabrotica virgifera virgifera (LeConte) (Coleoptera: Chrysomelidae), relies heavily on the planting of transgenic corn expressing toxins produced by the bacterium Bacillus thuringiensis (Bt). This has resulted in the evolution of resistance to all of the four commercially available Bt toxins targeting coleopteran insects. In this study, we evaluated the susceptibility of a Cry34/35Ab1‐resistant WCR colony in seedling and diet toxicity assays after removal from selection for six and nine generations. In addition, female fecundity, egg fertility, adult lifespan, larval development, and adult emergence were evaluated in two Cry34/35Ab1‐resistant and two susceptible WCR colonies to assess fitness costs. RESULTS Susceptibility to Cry34/35Ab1 was restored in a colony removed from selection after six and nine generations based on diet toxicity assays and comparisons of relative survival, head capsule width, and dry weight in plant assays. Thus, pronounced fitness costs associated with resistance to Cry34/35Ab1 were documented by susceptibility being restored within six generations. In separate studies evaluating specific fitness costs, larval fitness when reared on isoline corn did not differ between resistant and susceptible colonies. However, beetles from susceptible colonies lived longer than resistant beetles which resulted in females from susceptible colonies producing significantly more eggs than resistant colonies, with no differences in egg fertility. CONCLUSIONS The presence of a fitness cost that may contribute to the restoration of susceptibility to Bt has not been documented in other Cry3‐resistant WCR populations and could have significant impact on the deployment of resistance management practices. Published 2021. This article is a U.S. Government work and is in the public domain in the USA.