Abstract: Lysiphlebus fabarum (Marshall) is one of most important natural enemies of the soybean aphid, Aphis glycines Matsumura. Biological characteristics of L. fabarum including such indices as the developmental duration, breeding potential, longevity and sex ratios, and the emergence, feeding and parasitism behaviors of the parasitoid were observed under the laboratory conditions and described. The results showed that within the temperature of 19-31℃, the developmental duration gradually shortened with the increase of temperature. Most offsprings were produced at 22℃. At 19℃, the female adults had the longest longevity (12.9 d on average) when they were provided with 10% honey water as food. However, when the temperature reached to 31℃, the adult longevity was only 4.0 d. The sex ratio was 1.5∶1 at 19℃, and 1.3∶1 at 22℃; at higher temperatures (25℃, 28℃ and 31℃), however, more males were produced. The emergence period varies from 1.5 h to 3 h. Adult females can copulate and lay eggs on the day of emergence, and they usually choose the 2nd-3rd nymphs of the aphid to parasite. The results will be useful to guide the control of the soybean aphid in fields and provide basic knowledge on mass production, storage and utilization of L. fabarum in future.

Key words: Lysiphlebus fabarum; Aphis glycines, life history, behavior, developmental duration, longevity, emergence, breeding