Taxonomy of Aphelinidae (Hymenoptera: Chalcidoidea) from Taiwan

Chalcidoids are the most diverse group consisting of 22,000 described species in Hymenoptera. It is estimated that their total diversity could be from 60,000 to more than 500,000 species. Among them, the family Aphelinidae are smaller than average size (1.5 mm or less), containing 1,224 species in 32 genera. In spite of their small numbers, aphelinid parasitoids are major biocontrol agents of economically important pest species belonging to the hemipteran groups of coccoids, aphids and aleyrodids. However, the taxonomy of Taiwan aphelinids has not been established and poorly studied. Furthermore, since Dalman (1820) referred one Entedon species to the genus Aphelinus, no fewer than 102 genera were originally described in this family. Only since the middle of the 20th century did scientists begin vigorous attempts to study the types of described genera; this led to a drastic reduction in the number of genera to 32. However, the complex morphological features and complicated slide mounting make aphelinids as an extremely unpleasant and difficult group to study taxonomically. In this study, we provide a convenient, pellucid and permanent mounting method for aphelinids, and use plenty morphological drawings to make taxonomists feel easier to study these tiny insect groups. From 2008-2016, according to the collections and foreign academic exchanges, we provided a reliable key and revised Taiwan aphelinids, which currently include 108 species of 10 genera, including 7 new species and 25 new recorded species. The data shows a great biodiversity of Taiwan aphelinids because of the unique island with varied crops, plants and climate. We believe we can use these data to study the association between parasitoids, host insects and host plants in the future. This revision is just a beginning in that direction.