Tatsuya Ide

Discovery of a New Plagiotrochus Species (Hymenoptera: Cynipidae) Inducing Galls on the Evergreen Oak in Japan

ABSTRACT Plagiotrochus masudai Ide, Wachi & Abe sp. nov. (Hymenoptera: Cynipidae), a gall inducer on Quercus (Cyclohalanopsis) glauca Thunberg in Japan, is described. This is the first description of an oak gall wasp species (tribe Cynipini) inducing galls on Cyclohalanopsis. The unique life cycle of P. masudai takes 3 yr to complete. The adult wasps of the sexual generation emerge from bud galls on Q. glauca in spring of the first year, and those of the asexual generation emerge from twig galls in spring of the third year.

Discovery of a New Gall-Inducing Species in the Inquiline Tribe Synergini (Hymenoptera: Cynipidae): Inconsistent Implications from Biology and Morphology

ABSTRACT A new gall-inducing species of the inquiline tribe Synergini (Hymenoptera: Cynipidae), Synergus itoensis Abe, Ide & Wachi, sp. nov., from Japan is described. The morphological features of the adult clearly indicate that this new species is assigned to the genus Synergus Hartig, 1840, and members of Synergini have all been known as inquilines to date. Field observation showed that adult emergence of this gall wasp from acorns of the evergreen oak, Quercus (Cyclobalanopsis) glauca Thunberg, on the ground is well synchronized with the rapid growth period of fresh acorns in late summer. A rearing experiment demonstrated gall induction by S. itoensis in the seed coat of the acorn of Q. (C.) glauca under field conditions. Moreover, the occurrence of arrhenotoky in this gall wasp and lack of a significant effect of gall induction on acorn size were indicated. Judging from the inconsistency of biological and morphological features in S. itoensis, gall-inducing ability might have been regained within Synergini. The advantages and disadvantages of gall induction in acorns are discussed.

Three new species and a new record of cycloneuroterus (Hymenoptera: Cynipidae: Cynipini) inducing galls on cyclobalanopsis in Japan

ABSTRACT The following three new species of Cycloneuroterus Melika et Tang (Hymenoptera: Cynipidae: Cynipini) from Japan are described: C. akagashiphilus from Quercus (Cyclobalanopsis) acuta and C. hisashii and C. arakashiphagus from Q. (C.) glauca. Quercus (C.) acuta is recorded as a host plant of Cynipini for the first time. Cycloneuroterus fortuitusus Tang et Melika, previously known from Taiwan, is newly recorded for Japan. A key to all eight recognized species of Cycloneuroterus is provided. The hitherto known five species of Cycloneuroterus were recorded in Taiwan only and four of them induce galls on the strictly Asian subgenus Cyclobalanopsis. Therefore, the discovery of the three new species of Cycloneuroterus in Japan confirms the close association between Cycloneuroterus and Cyclobalanopsis, and suggests the existence of the potentially diverse cynipid fauna on this subgenus in Asia. More extensive sampling is expected to reveal the species richness in the Cynipini in the region.

Description of Two New Species of Dryocosmus (Hymenoptera: Cynipidae: Cynipini) Inducing Galls on the Strictly Asian Subgenus Cyclobalanopsis of the Genus Quercus, with a Key to Species of Dryocosmus in East Asia

ABSTBACT Two new species of Dryocosmus (Hymenoptera: Cynipidae: Cynipini), D. sefuriensis Ide, Wachi et Abe, sp. nov. and D. sakureiensis Ide, Wachi et Abe, sp. nov., are described from Japan. A key to species of Dryocosmus in East Asia is given. Although the members of Dryocosmus have been known to induce galls on the subgenus Quercus of the genus Quercus and the genera Castanea, Castanopsis, Chrysolepis, and Lithocarpus of Fagaceae, this is the first record of this gall wasp genus from the strictly Asian subgenus Cyclobalanopsis of the genus Quercus. The discovery of two new species of Dryocosmus associated with Q. (C.) acuta suggests the exceptionally diverse host range of Dryocosmus and the species richness of Cynipini on this plant subgenus in Asia.

A New Inquiline Species of Saphonecrus (Hymenoptera: Cynipidae: Synergini) Associated with Cecidomyiid Galls on Oak Trees in Japan

ABSTRACT A new inquiline oak gall wasp species, Saphonecrus yukawai Wachi, Ide & Abe, sp. nov. (Hymenoptera: Cynipidae: Synergini), is described from Japan. Although most inquiline oak gall wasps are associated with cynipid galls on Quercus trees, the adult wasps of S. yukawai emerged from galls induced by the gall midge Ametrodiplosis acutissima (Monzen) (Diptera: Cecidomyiidae) on Quercus (sect. Cerris) acutissima Carruthers. Host shift from cynipid galls to cecidomyiid galls in inquiline oak gall wasps is discussed.

Taxonomic Status of Two Species of Andricus (Hymenoptera: Cynipidae) Described by Shinji (1940, 1941) as Gall Inducers on Cyclobalanopsis

ABSTRACT Andricus shirakashii Shinji, 1940 and Andricus shirokashicola [sic] Shinji, 1941 (Hymenoptera: Cynipidae) were described from leaf galls on the evergreen oak, Quercus (Cyclobalanopsis) myrsinifolia Blume [Japanese: shirakashi], but their assignment to oak gall wasps (tribe Cynipini) has long been considered enigmatic. These species are in fact inquiline gall wasps that were described as gall-inducing wasps. Because the morphological characteristics of these species are typical of the genus Ufo (tribe Synergini), we transfer A. shirakashii and A. shirokashicola to this inquiline genus. Due to the loss of the type specimens of each species, the neotypes are here designated and the two species are redescribed.

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.

Discovery of Cynipidae (Hymenoptera: Cynipoidea) From the Indochina Region, With Description of Three New Species

ABSTRACT Plagiotrochus indochinensis Abe, Ide, Konishi, & Ueno sp. nov., Dryocosmus okajimai Abe, Ide, Konishi, & Ueno sp. nov., and Synophrus vietnamensis Abe, Ide, Konishi, & Ueno sp. nov. are described from Vietnam. This is the first record of Cynipidae (Hymenoptera: Cynipoidea) from the Indochina region; the former two species belong to tribe Cynipini and the latter to the inquiline tribe Synergini. Based on the observation of a female P. indochinensis inserting its ovipositor into a young sprout of Quercus (Cyclobalanopsis) helferiana A. de Candolle in the field, this wasp species is considered to induce galls on this evergreen oak species. This article confirms that members of Cynipini that induce galls on Cyclobalanopsis (the ring cup oaks) are widely distributed in Asia, as predicted previously. Although D. okajimai was collected by sweeping an evergreen Fagaceae tree, its host remains to be clarified. Because the adults of S. vietnamensis were collected by sweeping an evergreen Fagaceae tree in June and dissecting a bud gall on Castanopsis sp. in September, it is considered that this wasp species has more than one generation a year. The gall-inducing ability and host plant specificity of S. vietnamensis should be examined carefully in future. The high species richness of Quercus L. and related genera in the Indochina region increases the likelihood of the existence of little-known, but potentially diverse, cynipid fauna in this region.

Gall Inducers Arose from Inquilines: Phylogenetic Position of a Gall-Inducing Species and Its Relatives in the Inquiline Tribe Synergini (Hymenoptera: Cynipidae)

Abstract It has long been assumed that members of the cynipid tribe Synergini (sensu stricto) are all inquilines, that is, gallers of galls: the larvae can modify the galls of other species but cannot initiate gall formation on their own. Surprisingly, Abe et al. recently showed that one member of the tribe, Synergus itoensis Abe, Ide et Wachi, is a true gall inducer: it produces small galls inside acorns without the help of other species. Here, we present a comprehensive phylogenetic analysis of the Synergini to determine whether S. itoensis acquired this ability recently or if it represents a survivor of ancient gall inducers from which inquiline Synergini evolved. We studied 71 species belonging to five genera, covering all the Palearctic inquiline genera associated with oaks and one outgroup, Rhoophilus loewi Mayr, which is an inquiline in Lepidoptera galls on Searsia (formerly Rhus) (Anacardiaceae). We obtained partial sequences of cytochrome c oxidase subunit I and 28S ribosomal RNA (1.1 kbp of data). The results show that S. itoensis is most closely related to two undescribed species, which have also been reared from acorns. Their life history is unknown but the molecular phylogenetic data and the similarity in gall and adult morphology suggest that they are also gall inducers.The three species are deeply nested within lineages known to be inquilines, strongly suggesting that they acquired the ability to induce galls recently. Based on the molecular phylogenetic data and morphological features, Synergus yukawai (Wachi, Ide et Abe) is transferred back to Saphonecrus (Saphonecrus yukawai comb. rev.), where it was originally described.

Species status of Incisitermes spp. (Isoptera: Kalotermitidae) in Japan

The species status of Japanese populations of Incisitermes immigrans from Iwo and Minami Daito Islands was examined using mitochondrial 16S molecular barcode sequences. The molecular sequences of these two populations were compared to those of other Incisitermes spp. deposited in the GenBank database using a maximum likelihood phylogenetic analysis. This analysis suggested that the Minami Daito population is indeed I. schwarzi, as suspected previously, while the sequence of the Iwo Island population was identical to that of authentic I. immigrans. In addition to I. minor, which is recorded from middle and southern Japan, the presence of three Incisitermes species in Japan was confirmed.