Female calling behaviour and response of males to synthetic pheromone and virgin females in spring and summer generations of Hyphantria cunea (Lep., Arctiidae) (Drury) in Northeastern China

Abstract

Abstract: The Chinese population of Hyphantria cunea (Drury) was investigated regarding female calling, male flight, and male response to synthetic and natural pheromone. Special attention was given to the little studied spring generation. In the spring, (1st) generation females called in the beginning of the night, 19:30‐01:30, and the older females started calling earlier and calling lasted longer. During the summer, (2nd) generation females called in early morning, 03:45–04:50, with a 20 min peak just before sunrise. Pumping rate of the ovipositor ranged between 0.8–1.0 Hz and 1.1–1.2 Hz in spring and summer generation, respectively. Calling longevity of females was 4.7 ± 0.6 days (mean ± SEM) in spring and 3.6 ± 0.6 days in summer, respectively, and females 2–3 days old attracted most males. Synthetic baits (1,3Z,6Z‐9,10‐epoxyheneicosatriene: 3Z,6Z‐9,10‐epoxyheneicosadiene: 9Z,12Z,15Z‐octadecatrienal, at 1:1:8, total 5–6 mg/dispenser) had the same or higher catch than virgin females as baits. A bait with 2 mg loading was not competitive, while a 5 mg bait had good activity even when used during both generations. Change in dose of synthetics (1–3 ×) or number of females (1–6 ×) did not give a clear increase in response, while the coefficient of variation decreased with female number. Smaller sticky traps caught less than Uni‐traps (covered buckets with DDVp as killing agent), while a large cross‐barrier sticky trap caught equal to Uni‐trap but proved impractical. Height of trap placement was important in summer generation, when traps at 4 and 7 m caught 2 × and 4 × more than those at 2 m. The spring generation had a more uniform distribution of catch with height. Light intensity and air temperature affected male flight cativity, with temperature drop at dusk in 1st gen. and light increase at dawn in 2nd gen., repsectively, judged to be the most important for onset of male activity.