AC-DC electropenetrography (EPG) for in-depth studies of feeding and oviposition behaviors

Authors: Backus, Elaine; Cervantes, Felix; GUEDES, RAUL - Universidade Federal De Vicosa; Li, Andrew; WAYADANDE, ASTRI - Oklahoma State University

Submitted to: Annals of the Entomological Society of America
Publication Type: Review Article
Publication Acceptance Date: 2/4/2019
Publication Date: 3/13/2019
Citation: Backus, E.A., Cervantes, F.A., Guedes, R.N., Li, A.Y., Wayadande, A.C. 2019. AC-DC electropenetrography (EPG) for in-depth studies of feeding and oviposition behaviors. Annals of the Entomological Society of America. 112(3):236-248. https://doi.org/10.1093/aesa/saz009.
DOI: https://doi.org/10.1093/aesa/saz009

Interpretive Summary: Sixty years ago, invention of electropenetrography (EPG; also known as electrical penetration graph monitoring) solved a major challenge for research on insect pests, that is, how to study the feeding, host damage, and transmission of pathogens (plant and animal) by piercing-sucking pests. The piercing mouthparts penetrate opaque host tissues, preventing direct, visual observation. However, until recently, most EPG research was restricted to studies of aphids and leafhoppers on crop plants. Recent advances in EPG technology via the 3rd-generation, AC-DC monitor (electropenetrograph) are opening new doors to expand the science into all types of pest feeding and egg-laying. EPG can be used in three main ways for development of novel tactics of pest control. First, in cases where fundamental mechanisms of feeding damage or transmission of a pathogen are unknown, EPG can identify such mechanisms. Second, once the causes of damage or pathogen transmission are understood, EPG can be used to demonstrate effects of insecticides, antifeedants, repellants, or other chemical compounds on specific feeding behaviors that cause damage or facilitate transmission. Third, EPG can similarly identify effects of resistant versus susceptible plants or animals, including transgenic organisms genetically engineered to express biopesticides or other genes. The purpose of this paper is to encourage new research avenues by: 1) reviewing electronic principles and history of EPG, especially development of the new, AC-DC electropenetrograph, 2) reviewing principles underlying biological meanings of waveforms, and 3) presenting a few example waveforms from newly studied pests, specifically plant bugs, flies, mosquitoes, and ticks.

Technical Abstract: Studying the feeding, host damage, and transmission of pathogens (plant and animal) by piercing-sucking arthropods is challenging. The piercing mouthparts are probed/penetrated into opaque host tissues, precluding direct observation. This challenge was overcome by electropenetrography, or electrical penetration graph (EPG) monitoring, the most rigorous method to identify specific arthropod feeding behaviors. However, until recently, most EPG research was restricted to studies of aphid and leafhopper pests. Recent advances in EPG technology via the 3rd-generation, AC-DC monitor (electropenetrograph), are opening new doors to expand the science into all types of arthropod feeding and oviposition. EPG can be used in three main ways for development of novel integrated pest management (IPM) tactics. First, in cases where the fundamental mechanisms of feeding/oviposition effects or transmission of a pathogen are unknown, EPG is instrumental in identifying such mechanisms. Second, once causes of damage or pathogen transmission are understood, EPG can be used to demonstrate effects of insecticides, antifeedants, repellants, or other chemical compounds on specific feeding behaviors responsible for damage or transmission. Third, EPG can similarly identify effects of resistant versus susceptible varieties of crop plants or animals, including transgenic organisms genetically engineered to express biopesticides or other genes. The purpose of this paper is to encourage new research avenues by: 1) reviewing electronic principles and history of EPG, culminating in the new, AC-DC electropenetrograph, 2) reviewing principles underlying biological meanings of waveforms, and 3) presenting a few example waveforms from new taxa of arthropods, specifically Lygus hesperus plant bugs, Drosophila suzukii flies, Aedes aegypti mosquitoes, and Amblyomma cajennense ticks.