Evaluation of potential fitness costs associated with eCry3.1Ab resistance in Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae)

Authors: Geisert, Ryan; Hibbard, Bruce

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/10/2016
Publication Date: 5/4/2016
Citation: Geisert, R.W., Hibbard, B.E. 2016. Evaluation of potential fitness costs associated with eCry3.1Ab resistance in Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae). Journal of Economic Entomology. 109(4):1853-1858.

Interpretive Summary: The western corn rootworm has developed resistance to most control tactics used to manage it. This includes the use of transgenic corn varieties that express insecticidal Bt proteins. Because of this it is important to evaluate resistance dynamics in the western corn rootworm for the newest rootworm targeting Bt protein. This experiment was conducted in order to determine if there is fitness costs associated with resistance to this product for the western corn rootworm. The experiments indicated that there was no fitness costs associated with resistance to the product for rootworms. Data from these experiments help to show us the dynamics of resistance development as well as how quickly it could develop for rootworms.

Technical Abstract: Both an eCry3.1Ab resistant and paired control western corn rootworm, Diabrotica virgifera virgifera colony were tested for adult longevity, egg oviposition, egg viability, and larval development in order to evaluate the potential fitness costs associated with eCry3.1Ab resistance in the western corn rootworm. Adult longevity experiments were conducted by pairing virgin males and females together in plastic boxes supplied with food, water, and ovipositional medium and observed for survival time. Eggs were also collected from the ovipositional medium once a week to determine average egg oviposition and egg viability. Larval development time experiments were conducted by infesting seedling assays with twenty five neonate larvae and recording larval recovery after several days. Adult longevity, average egg oviposition, and larval development time indicated a lack of fitness costs associated with eCry3.1Ab resistance in the western corn rootworm. Results of egg viability indicated a fitness advantage for the eCry3.1Ab resistant colony with a significantly higher egg hatch than the control.