Thesis (M.Sc.)--Chulalongkorn University, 2015

Parasitic wasps are classified in the order Hymenoptera, same group as bees, ants and other wasps. Braconid wasps belong to the extremely diverse superfamily Ichneumonoidea. The characteristics of the braconid wasps are (1) fore wing without vein 2m-cu and/or with 1/Rs+M, (2) hind wing with 1r-m arising basal to split between R and RS, and (3) second and third metasomal tergites fusied. The aims of this research are to study the taxonomy of the nocturnal parasitic wasps, belonging to the family Braconidae on the Samaesan Islands and from the surrounding areas and construct the pictorial key of the parasitic wasp in the family Braconidae in subfamily level, including created the database of nocturnal braconids recorded from the study sites. In this study, 2 types of traps: black light trap and mobile bucket light traps were used to collect the specimens during September 2013 to September 2014. One hundred and seventy five morphospecies within 17 subfamilies (12 koinobionts and 5 idibionts) from 652 specimens have been collected and number of koinobiont specimens has been recorded more than the idiobionts in most of the collecting periods. A new record of Braconid subfamilies in Thailand have been reported for first time: Helconinae, Lysiterminae, Pambolinae, and Rhysipolinae. Most of the specimens are Cheloninae representing about 45% of all specimens (291 from 652 specimens) and the highest number of morphospecies belongs to the subfamily Cheloninae. Number of braconid species collecting from Khao Ma Cho is similar to those of Samaesan Island. Estimated species richness of the braconid species by Chao-1 in the study sites is approximately 271 species. Moreover, a new species of braconid wasp in the genus Aleiodes Wesmael, 1838 was also discovered in this study.