Stylet Penetration Behaviors of Megacopta cribraria, the Invasive Kudzu Bug, Using Electrical Penetration Graph Techniques

The kudzu bug, Megacopta cribraria, was first discovered in North America in 2009 and has spread through most of the southeastern United States, causing yield loss in soybean.  Since discovery, research has focused on managing this invasive pest,  and many important characteristics of the pest’s feeding behavior remain unknown. When the piercing-sucking mouthparts of phytophagous hemipterans are inserted into the plant, they become invisible to researchers and behaviors cannot be monitored. The electrical penetration graph technique is a tool that allows researchers to overcome this difficulty so feeding behavior experiments can be performed. Feeding activities performed by an insect wired into an electrical circuit, are converted into waveforms which can be quantified and analyzed.  Study objectives were to provide the first documentation and characterization of M. cribraria waveforms and to determine waveform biological meaning through histology. Adult females probed soybean stems 1.4 ± 0.97 times in nine hours with an average probe time of 2.27 ± 1.30 hours. Mouthparts were shown to terminate in the phloem. Results can be used in conjunction with the development of  resistant soybean varieties as well as providing a baseline for further research on the feeding behaviors of the kudzu bug and other soybean-feeding hemipterans.