Survival Rate, Food Consumption, and Tunneling of the Formosan Subterranean Termite (Isoptera: Rhinotermitidae) Feeding on Bt and non-Bt Maize

Abstract

Although several termite species were reported to be susceptible to some Bacillus thuringiensis (Bt) subspecies, no research has been conduced to evaluate the possible non-target effect of genetically modified (GM) Bt crops on termites. In this study, plant tissues of three commercial planted Bt maize (YieldGard* Corn Borer, Genuity* VT Triple PROTM and Genuity* SmartStaxTM) and two non-Bt maize hybrids were provided to Formosan subterranean termite, Coptotermes formosanus, as food. Five food sources including wood blocks and filter paper treated with maize leaf extract as well as leaves, stalks, and roots of maize were tested in the laboratory. The experiment was maintained for two weeks and the survival rate of termites, food consumption, and tunneling behavior were recorded. The results revealed no significant differences in survival rate, food consumption and length of tunnels between termites feeding on Bt and non-Bt maize planting materials, indicating that Bt proteins expressed in the three Bt maize products did not negatively affect C. formosanus. However, compared to wood block and filter paper treatments, termites feeding on maize tissues showed different consumption pattern and tunneling behavior. Our study also suggests that maize stalk is a good candidate for termite bait matrices.