Biological Characteristics of Two Natural Enemies of Thrips, Orius strigicollis (Poppius) and O. laevigatus (Fieber) (Hemiptera: Anthocoridae)
With the comparison of native Orius strigicollis (Poppius) to European O. laevigatus (Fieber), we investigated biological characteristics such as developmental period, fecundity, life span, predation ability, and augmentation after release. Experiments were carried out at five temperature condition, 15℃, 20℃, 25℃, 30℃, and 35℃. In the case of O. strigicollis, egg period was 3.1~14.9 days (hatchability: 46.7~88.2%), and developmental period of nymphs was 9.4~42.8 days (survival rate: 2.4~96.5%). Fecundity at each temperature was 28.1, 107.9, 123.6, 127.3, and 18.1, respectively. Life span of adults was 63.4, 40.1, 22.1, 18.3, and 11.0 days, respectively. In the case of O. laevigatus, egg period was 3.1~13.5 days (hatchability: 65.0~89.9%), and developmental period of nymphs was 9.3~42.0 (survival rate: 4.3~80.6%) days. Fecundity at each temperature was 101.8, 218.6, 224.5, 219.5, and 15.7. Life span of adults was 70.6, 66.4, 32.6, 34.5, and 7.3 days, respectively. In long-day condition (16L:8D), fecundity of O. strigicollis and O. laevigatus was 105.8 (18℃)~142.4 (25℃) and 109.5 (18℃)~191.5 (25℃), respectively. In short-day condition (10L:14D), fecundity of them was 1.0 (18℃)~31.8 (25℃) and 63.0 (18℃)~198.8 (25℃), respectively. Daily prey consumption of second instar Frankliniella occidentalis was 14.3 and 10.9, respectively. In greenhouse, density of O. strigicollis begins to increase from mid May and peaked about early July (1.8 individual/flower), while that of O. laevigatus begins to increase from mid March and peaked about early June (6.6 individual/flower).