Influence of chemical cues from host plants on the behavior of neonate Estigmene acrea larvae (Lepidoptera: Arctiidae)

The role of the chemical cues during the host-finding behavior of neonate Estigmene acrea (Drury) larvae was studied in the laboratory using olfactometer bioassays. Three host plant species of E. acrea were used in the experiments: soybean, Glycine max L. Merr.; tomato, Lycopersicum esculentum Miller; and maize, Zea mays L. The number of larvae showing an attraction toward the leaf volatiles of individual test plants was significantly higher than toward the control air in single-choice olfactometer bioassays. In dual-choice tests, larvae showed a clear preference for the volatiles from soybean over the volatiles from maize and tomato leaves, In contrast, larvae did not show any preference for the maize and tomato volatiles, The locomotory behavior of larvae was clearly affected by hexanic and methanolic soybean extracts. Larvae spent more time walking and walked more distance on the zones containing soybean extracts than on the zones treated with maize and tomato extracts and control solvents. The feeding preference tests revealed that larvae prefer feeding on soybean over maize and tomato foliages.