Substrate-mediated feeding and egg-laying by spotted wing drosophila: waveform recognition and quantification via electropenetrography

Authors: GUEDES, RAUL NARCISCO - Universidade Federal De Viçosa; Cervantes, Felix; Backus, Elaine; Walse, Spencer

Submitted to: Journal of Pest Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/14/2018
Publication Date: 11/24/2018
Citation: Guedes, R.C., Cervantes, F.A., Backus, E.A., Walse, S.S. 2018. Substrate-mediated feeding and egg-laying by spotted wing drosophila: waveform recognition and quantification via electropenetrography. Journal of Pest Science. 92(2):495-507. https://doi.org/10.1007/s10340-018-1065-y.
DOI: https://doi.org/10.1007/s10340-018-1065-y

Interpretive Summary: Crop damage cause by insect pests can be minimized through an understanding of feeding and foraging habits. Toward this end, we electronically monitored, using electropenetrography (EPG), the behavior of adult spotted wing drosophila on two substrates, artificial diet and strawberry fruits. Three substrate-associated behaviors were diagnosed: non-probing, feeding, and egg-laying. Dabbing and ingestion occurred during feeding, while abdominal probing and egg-laying constituted the egg-laying phase. The egg-laying phase was similar on diet and strawberry. In contrast, the non-probing was more frequent, but shorter on diet, where feeding lasted longer and was more frequent. Dabbing was more frequent and lasted longer on diet, while ingestion events per insect lasted longer on strawberry. These findings show that EPG is a valuable tool for characterizing feeding and foraging behaviors and should springboard future studies on deterring such activities on agriculturally-valuable crops.

Technical Abstract: Substrate suitability is a key determinant of feeding and egg-laying decisions by arthropods and rigorous observation of such activities provides important management insight. Electropenetrography (EPG) was used to analyze feeding and egg-laying by the spotted wing drosophila (Drosophila suzukii (Matsumura)) on artificial diet and strawberry fruits. Three behavioral phases were recognized on both substrates: non-probing, feeding, and egg-laying. The non-probing phase encompassed a family of waveforms consisting of resting (coded as Z), grooming (G), and walking (W). The feeding phase encompassed waveforms representing substrate dabbing (D) and ingestion (I), while the egg-laying phase encompassed abdominal probing (P) and egg-laying (L) per se. The egg-laying phase was similar on diet and strawberry. In contrast, non-probing events were more frequent, but shorter, leading to less overall non-probing on diet compared with strawberry. Dabbing was more frequent and lasted longer overall on diet, but ingestion events lasted longer on strawberry. Therefore, although the flies fed (dabbed and ingested) for longer overall on diet, each ingestion event was longer on strawberries. Our results suggest that strawberry fruits are a more suitable and preferred food source because they led to extended periods of sustained ingestion. These findings demonstrate the first application of EPG for characterizing substrate-specific feeding and egg-laying behaviors of a key phytophagous pest, offering intriguing insight into management as well as host selection behaviors.