Feeding behavior of Leptoglossus phyllopus (Hemiptera:Coreidae) developmental stages

Leptoglossus phyllopus (Hemiptera: Coreidae) is considered a minor economic problem, but research on its feeding behavior could be useful in understanding congeneric leaffooted bug species that pose a greater economic threat. The objective of this research was to examine probing behavior of juvenile and adult bugs using Electrical Penetration Graph (EPG) techniques.

Leaffooted bugs were laboratory-reared on green beans and sunflower seeds and aged by separating juveniles immediately after molt. Newly molted nymphs were fed for 24 hours and then starved for 24 hours. Adult males used in EPG trials ranged in age from 1-2 weeks, and were also starved 24 hours prior to testing.

Feeding was monitored for 9 hours using a AC-DC 4-channel EPG monitor (Bennett Electronics, Columbia, Missouri) and Windaq-Lite® software (Dataq Instruments, Akron, OH). Recognizable voltage spikes (waveforms) indicated stylet insertion into the green bean. Feeding behaviors of third, fourth, and fifth instar nymphs and adults on green beans were analyzed (10 insects per developmental stage).

Probe frequency and duration per insect, probe duration per probe (i.e., a single feed), time until first probe per insect, and length of pathway of each probe were compared. Significant differences appear between juveniles vs. adults for probe frequency and length of pathway, indicating that adults eat more frequently and locate the feeding site faster than nymphs. Knowledge of the most damaging stages can aid in timing of control. Further study will allow comparisons between coreids and other Heteroptera and correlations of waveforms with ingestion and salivation behaviors.