Feeding assay to test bioactive peptide effects on survival in Western flower thrips

Western flower thrips (WFT), Frankliniella occidentalis (Thysanoptera: Thripidae), is a polyphagous pest known for its small size and wide host range. These characteristics, plus their short generation time and ability to transmit diseases such as impatiens necrotic spot virus and tomato spotted wilt virus, make them a devastating nursery crop pest with insecticides as the main form of control. WFT can quickly develop resistance to insecticides, and the environmental and human health impacts emphasize the need for alternative methods of management. Insect neuropeptides and receptors are often proposed as targets for species-specific, non-toxic insect control, as they control biological processes important for survival.

In using modified neuropeptides, we can block the active site of the target receptor, rendering it dysfunctional, leading to negative effects on the insect’s survival. It is important to test the effects of the peptides on the insect using a feeding assay as the ideal procedure. We tested several modified neuropeptides by mixing them with a sugar solution and feeding them to individual male thrips, and the mortality of the thrips was monitored daily. This procedure proved difficult, taking into consideration WFTs microscopic size and constant erratic movement, making the development of a reliable and consistent strategy crucial for the feeding assay’s success.

In this presentation, we outline the steps taken to achieve a successful feeding assay to assess WFT survival, as well as the analysis and significance of the results of several trials performed in the lab.