Velvetbean Caterpillar: Response of Males to Virgin Females and Pheromone in the Laboratory and Field

Abstract

Observations of the sexual behavior of A. gemmatalis (Hubner) were made in the laboratory and field during 1976. The calling behavior of the female is characteristic of many moth species in that the tip of the abdomen is curved upward when calling. In the laboratory, males fly in a zig-zag path toward calling females or to pheromone extracts. Clasper extension by some males was observed as they approached the pheromone source. Females began calling about 2 h after sunset and this behavior continued intermittently throughout the scotophase. Mating and increased age greatly reduced the attractiveness of females to males in field traps. Pheromone was obtained from non-calling and calling females. In field bioassays, extracts from females collected before and after dark were effective in attracting males, with extracts taken at 4 and 6 h after dark capturing the most males. Seven trap designs were evaluated for effectiveness at capturing A. gemmatalis males, but only the electric grid trap proved efficient and warranted further use.