Cynipidae (Hymenoptera: Cynipoidea) on Cyclobalanopsis (Fagaceae) in Mainland China, with the First Record of Sexual Generation of Cynipini in Winter

Abstract

Cycloneuroterus wangi Abe, Ide, & Odagiri sp. nov. and Dryocosmus nanlingensis Abe, Ide, & Odagiri sp. nov. are described from Mainland China. Gall wasps associated with Quercus (Cyclobalanopsis) sessilifolia Blume, which is distributed in Japan, Taiwan, and Mainland China, have not yet been recorded. However, this evergreen oak species is considered to be the host plant of C. wangi on the basis of an observation in which eight females of this gall wasp species inserted their ovipositors into the buds of Q. (C.) sessilifolia. This is the first record of the Cynipidae (Hymenoptera: Cynipoidea) being associated with Cyclobalanopsis from Mainland China. As cynipids associated with Cyclobalanopsis have previously been known from Japan, Taiwan, and Vietnam, the discovery of C. wangi indicates that oak gall wasps associated with Cyclobalanopsis are widely distributed in Asia, as predicted previously. The collection of an adult male of D. nanlingensis by sweeping Fagaceae trees represents the first observation of a sexual generation of Cynipini in winter. Further investigations are necessary to elucidate the life cycle and to identify the host plant of D. nanlingensis. Cynipid species richness in broadleaf forests dominated by Fagaceae is considered to be high in Mainland China because of remarkable diversity of potential host plants, such as oaks and related taxa.

Heterogony in Cycloneuroterus (Hymenoptera: Cynipidae: Cynipini) From Rearing Experiments and DNA Barcoding

“…zhuili are similar to those of the chestnut gall wasp Dryocosmus kuriphilus Yasumatsu, which reproduces asexually without males, D. zhuili reproduces bisexually and, unlike all other species of Cynipini, is considered to have one sexual generation in 1 yr (Zhu et al 2015, Pang et al 2018). In addition, Dryocosmus nanlingensis Abe, Ide, and Odagiri was described based only on one male from China, indicating that it is the sexual generation (Abe et al 2014). However, this male was collected in winter (December), which is typically the emergence period of the asexual generation in most species of Cynipini (Abe et al 2014).…”

“…Cycloneuroterus Melika and Tang is a genus of Cynipini that contains 17 species, known from Taiwan, Japan, and mainland China (Tang et al 2011, 2016; Ide et al 2012; Abe et al 2014). All but one species are described based only on the sexual generation adult.…”

“…The adult female of C . wangi Abe, Ide, and Odagiri examined by Abe et al (2014) was considered to be the asexual generation because of its emergence period, but the sexual generation wasp remains unknown (Abe et al 2014). Therefore, there are no Cycloneuroterus species for which the morphology of both sexual and asexual generation adults is known.…”

New Dryocosmus Giraud species associated with Cyclobalanopsis and non-Quercus host plants from the Eastern Palaearctic (Hymenoptera, Cynipidae, Cynipini)

“…Only one cynipine species, Cycloneuroterus wangi Abe, Ide, & Odagiri, 2014, has been reported to oviposit on Cyclobalanopsis outside Japan, Taiwan and Vietnam despite the wide Asian distribution (Abe et al 2014) of this Quercus subgenus. Although Dryocosmus species have been collected in Yunnan province of southern China (Abe et al 2014b) and in the Indochina region (Abe et al 2014a), their host associations are unknown. Although all Cyclobalanopsis associated Drycosmus species-including the five new species of the present paper-are known from Taiwan (Table 2), we can not confirm or deny if this restricted distribution is due to sampling bias.…”

“…Males and females of the sexual generation usually occur at the same time as the flush of new growth on host plants in the spring, while the parthenogenetic females of the asexual generation occur in the winter (Csóka et al 2005, Abe et al 2014b). Of the 22 described Eastern Palaearctic Dryocosmus, no species are known to have alternate sexual and asexual generations; asexual specimens are known for four and sexual for 18 species (Table 2).…”