Calling Behavior of the Female German Cockroach, Blattella germanica (Dictyoptera: Blattellidae)

the first time, to exhibit a characteristic calling behavior during which females emit a volatile sex pheromone. Under a photoperiod of l2L: 12D, the percentage of 7-day-old virgin females that exhibited this behavior peaked before the end of the scotophase in a similar pattern to the diel periodicity of mating. A clear relationship was evident between calling and stages of sexual receptivity during successive gonotrophic cycles. Females initiated calling 5-6days after the imag-inal molt, when their basal oocytes were 1.6 mm long. If not mated, females continued to exhibit bouts of calling during the next 3-4 days until 24 h before ovulation. Calling was completely suppressed by mating as well as the presence of an egg case in the genital atrium in both virgin and mated gravid females. We suggest hat calling and the emission of a volatile sex pheromone serve to attract males from a distance as well as to potentiate responses to contact sex pheromone in aggregations. KEY WORDS: German cockroach; Blattella germanica; calling behavior; sex pheromone