In the northern rice-growing areas, Haplogonatopus oratorius is the dominant natural enemy species of Laodelphax striatellus among dryinid wasps. Its population dynamics are closely related to external environmental factors. This study aims to clarify the effects of temperature and pesticides on the main biological parameters of H. oratorius under laboratory conditions.
Five temperatures (12, 18, 24, 30, and 36 ℃) were set to examine their effects on the predation, parasitism, and adult longevity of the parental generation of H. oratorius, as well as on the cocooning rate, emergence rate, female proportion, and developmental duration of its offspring. Additionally, the lethal effects of two concentrations of chlorantraniliprole, abamectin, and pymetrozine were tested on the main developmental stages (parasitized hosts, cocoons, and adults) of H. oratorius.
1) Under different temperature conditions, the highest predation rate of H. oratorius was 20.5% (at 18 and 24 ℃), and it gradually decreased from 18 to 36 ℃, with the lowest rate being 9.0% (at 12 ℃). The highest parasitism rate was 30.5% (at 30 ℃), which gradually increased from 12 to 30 ℃, and the lowest rate was 12.0% (at 36 ℃). Adult longevity was longest at 18 ℃ (21.7 days for females, 3.7 days for males) and the shortest at 36 ℃ (2.8 days for females, 1.3 days for males). The cocooning rate (85.7%), emergence rate (76.2%), and the female proportion (38.1%) of offspring were all highest at 24 ℃, while no offspring survived at 36 ℃. 2) When parasitized hosts (5 and 12 days post-parasitism) were treated with the tested insecticides, the mortality caused by chlorantraniliprole ranged from 62.5% to 75%, whereas abamectin and pymetrozine both caused 100% mortality. For cocoons treated for 3 and 7 days, mortality ranged from 3.3% to 30.0% for all tested insecticides. For adult females and males, abamectin caused 48-h mortality of 73.3%-90.0%, while chlorantraniliprole and pymetrozine caused 48-h mortality of 36.7%-73.3%.
The suitable temperature range for H. oratorius is 18-30 ℃; survival rate decreases significantly at both low and high temperatures, and no survival was observed at 36 ℃. The wasp shows relatively strong tolerance to insecticides during the cocoon stage.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |