Abstract:

Objective: Grassland caterpillars, Gynaephora spp. (Lepidoptera:Lymantriidae), attack many plants in the Sanjiangyuan Nature Reserve which is in Qinghai-Tibet Plateau. For protecting the vegetation there it is essential to control the pests with non-pollution techniques. We investigated the insect natural enemies of the caterpillars and tried to use them for biocontrol. Methods: We collected pupae of G. qinghaiensis which is widely distributed in the Reserve and brought them to lab for rearing parasitoids.Then the parasitism rate was counted and the natural enemies were classified. Results: A new parasitoid species, Pteromalus sanjiangyuanicus Yang (Hymenoptera:Pteromalidae), was found parasitizing the pupae of Gynaephora qinghaiensis during the survey by taxonomic study. In this paper, the morphological characteristics of the new species of parasitoid were described in detail, and clear color photos of morphological characteristics were provided. The basic information of its biology and distribution is also provided. Meanwhile, a key to distinguish the new species from the closed species P. qinghaiensis Liao 1987 is provided. The characters below are different from the latter species:Female antennae black-brown only with base part of the scape dark-yellow; metasoma dark-brown with slight purple luster; all coxae having same color with mesosoma and others yellow-brown; notauli appearing at anterior 1/3 of mesonotum and although they are weak but distinct; forewing with marginal vein 1.3 times as long as stigmal vein; dorsellum with a sharp carina which like a "V" and its anterior part concave with about 10 short longitudinal carinae in concave area, length of the area about as long as frenal area of scutellum (22:24) medially; propodeum with median carina exist at basal 1/3 although it is weak; upper mesepimeron reticulate and not smooth and shining. Male antennae dark-brown and metasoma only 0.8 times as long as mesosoma. Conclusion: In the present survey, a new parasitoid species has been found and is a new natural enemy which has high potential for biocontrol of the caterpillar. The types of the new species are kept in the Insect Collection, Chinese Academy of Forestry, Beijing, China.

Key words: Gynaephora qinghaiensis, insect natural enemy, Pteromalus sanjiangyuanicus, new species, parasitoid, biocontrol