Abstract:

This paper reports a kind of obligate pest that damages the leaves of Manglietia yuyuanensis in Fujian province. The pest is a new species of Tenthredinidae, Cladiucha huangbki Niu & Wei sp. nov. Its potential distribution area includes northern Guangdong, Zhejiang, Jiangxi and Hunan. Cladiucha huangbki is the most similar to C. megatheca Wei, but differs from the latter with smaller body; the female antenna clearly longer than twice head breadth with 22 + 3 antennomeres; malar space 0.4 times as long as diameter of median ocellus; the middle fovea shallow and without a deep pit; the lateral furrows of postocellar area distinctly divergent; the middle serrulae of female lancet flat; and the host plant is M. yuyuanensis. The mitochondrial genomes of three Cladiucha species have been sequenced. C. huangbki and C. punctata Wei are divergent in morphology, but similar in the mitochondrial genome. The COⅠ and other 11 protein-coding genes have high similarity, but the P distance of the two nad2 genes is 4.86%. This is the first reported case within Symphyta of Hymenoptera that the difference between the COⅠ genes of the closely related species of a genus is very small but the difference between the nad2 genes of them is distinct. In order to facilitate the identification of the sawfly pests on Magnoliaceae, a key for world Cladiucha species is provided.

Key words: Hymenoptera, Tenthredinidae, Megabelesinae, Cladiucha, China, Magnoliaceae