Taxonomy and distributional pattern of Pimplinae (Hymenoptera: Ichneumonidae) from Vietnam

Abstract

This monographic study of Vietnamese Pimplinae is based on several recent publications of the author that are integrated herein to a complete review.<br /> Although Vietnam is one of the global biodiversity hotspots, the ichneumonid fauna of this country is still poorly studied. Pimplinae is a moderately large subfamily of Ichneumonidae with more than 1500 recognised species in 77 genera. However, only 39 pimpline species belonging to nine genera were documented from Vietnam until 2009. Our recent collection revealed that the diversity of the Vietnamese Pimplinae is in fact considerably higher, with numerous hitherto new records and undescribed species. Taking this situation, this study aims to fill the taxonomic gaps and to improve the knowledge about species richness and distributional patterns of pimpline wasps in Vietnam.<br /> Field surveys were conducted for a period of 15 years (1997–2012) in 31 provinces, including 26 national parks and nature reserves. Taxonomic decisions were based on morphological examination of more than 900 specimens.<br /> In the first part, a taxonomic review of pimpline waps in Vietnam and an identification key to the 21 genera is provided. All Vietnamese genera can be assigned to five genus-groups of two tribes: The Pimpla and Theronia groups belong to the tribe Pimplini, and the Camptotypus, Ephialtes and Sericopimpla groups belong to the tribe Ephialtini. A taxonomic review of each genus-group is presented in separate chapter.<br /> Chapter 1 is a taxonomic revision of the Pimpla genus-group in Vietnam. Five genera are included in this genus-group: Echthromorpha, Itoplectis, Lissopimpla, Pimpla and Xanthopimpla. A total of 73 species are listed with descriptions of 14 new species of the genus Xanthopimpla and two new species of the genus Pimpla. Twenty-three species were reported as new for Vietnam, including 17 species of Xanthopimpla, five species of Pimpla and one species of Lissopimpla. One species, Pimpla rufipes (Miller, 1759), was found as a misidentification and excluded from the ichneumonid fauna of the country. In addition, a number of subspecies of the genus Xanthopimpla were synonymized. Keys to the species of the two genera, Pimpla and Xanthopimpla, are also presented.<br /> Chapter 2 is a taxonomic review of the Vietnamese species of the Theronia genus-group. This genus-group is represented in Vietnam by 14 species in five genera, viz. Augerella, Epitheronia, Nomosphecia, Parema and Theronia. An identification key to the species is provided for each genus. Seven new species were discovered (Theronia: 3 new species, Augerella: 2 new species, Epitheronia and Nomosphecia: 1 species each). Five species are recorded for the first time from Vietnam, comprising two species of Theronia, two species of Nomosphecia and one species of Augerella. The species Nomosphecia brevicauda (Cushman, 1933) is transferred to the genus Augerella, A. orientalis (Gupta, 1962) is synonymized with A. brevicauda. Moreover, one subspecies, Nomosphecia zebroides indicus (Gupta, 1962), is synonymized with the nominate subspecies.<br /> Chapter 3 presents a taxonomic review of the Vietnamese species of the Camptotypus genus-group. Only the genus Camptotypus, with four species, is known from this country. One new species, C. trui Pham, Broad & Wägele, 2012, was described based on material collected from Central Vietnam. The two species, C. olynthius and C. testaceus, are recorded as new for the country. A key to four Vietnamese species of Camptotypus is compiled.<br /> Chapter 4 is a taxonomic revision of the Ephialtes genus-group. This genus-group is represented by three genera: Dolichomitus, Flavopimpla and Leptopimpla, with six species in Vietnam. Descriptions of three new species: Dolichomitus lami Pham, Broad & Zwakhals, 2012, Flavopimpla lanugo Pham, Broad & Wägele (under review) and F. vinhcuuensis Pham, Broad & Wägele (under review) are provided. Moreover, two species are recorded as new for Vietnam: Dolichomitus melanomerus (Vollenhoven) and Flavopimpla latiannulatus (Cameron). Keys to species are compiled.<br /> In chapter 5, a taxonomic review of the Vietnamese species of the Sericopimpla genus-group is provided. Of this genus-group seven genera are represented in the country: Acrodactyla, Acropimpla, Brachyzapus, Chablisea, Gregopimpla, Sericopimpla and Zaglyptus. An identification key to species is compiled for each genus. A total of 25 species are documented. Descriptions of 18 new species are provided (Acrodactyla and Brachyzapus: 6 new species each, Acropimpla: 3 new species, Chablisea: 2 new species and Zaglyptus: 1 new species). In addition, six species are reported as new for Vietnam, including 2 species of Acropimpla, 2 species of Zaglyptus, 1 species of Gregopimpla and 1 species of Sericopimpla. <br /> The discussion summarizes the current knowledge of the diversity and taxonomy of Pimplinae from Vietnam. Of 122 recognized species in 21 genera, 12 genera and 38 species are new records for the country and 45 species are new for science. The distributional patterns of pimpline wasps are discussed. Comparisons of species compositions among geographical regions, habitat types and altitudinal zones were made on the basis of cluster analyses. In terms of geographical distribution, most species of Pimplinae occur in the northwestern region (74 species). The species richness of Pimplinae in the South Central and Central Highland (55 species) and in the North Central region (50 species) is higher than in South Vietnam (40 species) and in the northeastern region (39 species). The northwestern and South Central and Central Highland regions have also the highest level of endemicity with 22 species and 18 species (29.7% and 32.7% of the total species number known from these regions respectively). The northwestern and South Central and Central Highland regions also harbour the highest level of new discoveries of Pimplinae in Vietnam, with 20 and 16 newly described species. Two hotspots of new discovery of Pimplinae in Vietnam are Hoang Lien NP (12 new species) and Chu Yang Sin NP (10 new species). The similarity of species compositions between the northeastern and northwestern regions, between the North Central Vietnam and South Vietnam are closer than those of other regions. Except the species composition of Pimplinae in South Vietnam, those of other geographical regions are clearly different from the South Central and Central Highland region. Concerning the altitudinal distribution, the collecting sites of Pimpline in Vietnam can be divided into three levels of elevation: (I) below 700 m a.s.l., (II) between 700 and 1,200 m a.s.l.; and (III) above 1,200 m a.s.l. Zone I harbours 90 species (73.8% of the total number species). The species diversity decreases at higher elevations: the species numbers found in zones II and III are 47 and 27 species, respectively. Most species in zone III (20 species) were collected from Hoang Lien NP in Lao Cai Province. In terms of habitat types, there are eight major vegetation types in Vietnam. A total of 94 species were found in evergreen lowland forests on silicate rocks at elevations of 0–1000 m a.s.l. The species richness of Vietnamese Pimplinae in the evergreen montane and highland forests on silicate rocks between 1000–3000 m a.s.l. (41 species), the secondary, wet and agricultural plant communities, timber and industrial plantations (37 species each) and in the evergreen broad-leaved lowland forests on alkaline soils (30 species) is much higher than in the deciduous dry lowland forests and savanna-like woodlands (6 species) as well as in the evergreen and semi-deciduous broad-leaved, mixed and coniferous limestone montane forests (5 species) and the semi-deciduous dry lowland forests (2 species). The species compositions in evergreen forests and agricultural habitats are more similar to each other (clustered in the same group) than the four other habitat types (semi-deciduous and deciduous forest and coastal habitat).