A new species of Habrophorula from Vietnam and an updated key to species of the genus (Hymenoptera, Apidae).

The rare bee genus Habrophorula Lieftinck, 1974 is recorded for the first time from Vietnam. The genus is represented by a new species, Habrophorulabelladeceptrix Tran, Engel & Nguyen, sp. nov., from Cao Bang Province and can be most easily confused with H.nigripes Wu from China. The species is most easily differentiated by the unique form of the male terminalia but can also be distinguished by differences in integumental and setal coloration. A revised key is provided to the species of the genus. Females of the new species were collected at flowers of Saurauiaroxburghii Wall. and Saurauianapaulensis DC. (Actinidiaceae); males were collected at flowers of Lantanacamara L. (Verbenaceae).

The solitary wasp genus Orancistrocerus from Vietnam, with descriptions of two new species (Hymenoptera, Vespidae, Eumeninae).

New data are presented for the potter wasp genus Orancistrocerus van der Vecht (Eumeninae, Odynerini) occurring in Vietnam. Two species are described as new to science: Orancistrocerusthanhnhatsp. nov. and O.thanghensp. nov.Orancistrocerusaterrimuserythropus van der Vecht is synonymized with Orancistrocerusaterrimusaterrimus (de Saussure); the male genitalia of this species are described for the first time. An updated key is presented to all species of the genus.

Discovery of the male of Okinawepipona yty Nguyen, 2018 (Hymenoptera: Vespidae: Eumeninae) from Vietnam.

The male of Okinawepipona yty Nguyen, 2018 is described and illustrated for the first time, together with its genitalia, based on specimens from Y Ty, Lao Cai, Vietnam. In addition, the male genitalia of O. curcipunctura Nguyen & Xu, 2014 is also described for the first time. Based on these descriptions, a discussion is provided regarding the male genitalia of eumenine wasps in general.

The potter wasp genus Allorhynchium from Vietnam, with descriptions of three new species and a new country record (Hymenoptera, Vespidae, Eumeninae).

Species of the potter wasp genus Allorhynchium van der Vecht (Eumeninae: Odynerini) occurring in Vietnam are presented. Seven species have been recorded from Vietnam. Of them, three species are described as new to science: Allorhynchiumlatum Nguyen, Tran & MT Nguyen, sp. nov., A.moerum Nguyen & AD Nguyen, sp. nov., and A.setosum Nguyen & Engel, sp. nov., and one species, A.argentatum (Fabricius, 1804), is recorded from Vietnam for the first time. An updated key to the Oriental species of the genus is presented.

The bee genus Anthidiellum in Vietnam: descriptions of five new species and the first male of Anthidiellumcoronum (Hymenoptera, Megachilidae).

The Vietnamese fauna of bees in the Anthidiellum Cockerell (Megachilinae, Anthidiini) is reviewed. Seven species are recognized, representing two subgenera. Five new species are described and figured as: Anthidiellum (Clypanthidium) nahang Tran, Engel & Nguyen, sp. nov., A. (Pycnanthidium) ayun Tran, Engel & Nguyen, sp. nov., A. (P.) chumomray Tran, Engel & Nguyen, sp. nov., A. (P.) flavaxilla Tran, Engel & Nguyen, sp. nov., and A. (P.) cornu Tran, Engel & Nguyen, sp. nov. from the northern and central highlands of Vietnam. Two previously described species are newly recorded for the fauna: A. (P.) carinatum (Wu) and A. (P.) coronum (Wu), with the male of the latter species described and illustrated for the first time. An identification key is provided for all species of Anthidiellum occurring in Vietnam.

Carriage of Plasmid-Mediated Colistin Resistance-1-Positive Escherichia coli in Humans, Animals, and Environment on Farms in Vietnam.

Plasmid-Mediated Colistin Resistance 1 (mcr-1) was first reported in 2015 and is a great concern to human health. In this study, we investigated the prevalence of mcr-1 and mcr-1-positive Escherichia coli (MCRPEC) and the association in infection status among various reservoirs connected to livestock. The study was conducted in 70 poultry and swine farms in a commune in Ha Nam province, northern Vietnam. Samples were collected from farmers, food animals, domestic animals, and farm environments (flies and wastewater) for polymerase chain reaction (PCR) screening for mcr-1 gene and species identification of PCR positive isolates. Among 379 obtained mcr-1 positives isolates, Escherichia coli was the major identified, varying from 50% (2/4) in dog feces to 100% (31/31) in humans feces isolates. The prevalence of MCRPEC was 14.4% (20/139), 49.7% (96/193), 31.3% (25/80), 36.7% (40/109), 26.9% (18/67), and 3.9% (2/51) in humans, chickens, pigs, flies, wastewater, and dogs, respectively. The study identified association between MCRPEC infection status in humans and flies (OR = 3.4), between flies and chickens (OR = 5.3), and between flies and pigs (OR = 9.0). Farmers' age and farm livestock unit were also associated factors of MCRPEC infection status in humans (OR = 5.1 and 1.05, respectively). These findings bring new knowledge on antibiotic resistance in livestock setting and important suggestions on potential role of flies in the transmission of mcr-1 resistance gene.

A new genus of minute stingless bees from Southeast Asia (Hymenoptera, Apidae).

A new genus of minute stingless bees (Meliponini: Hypotrigonina) is described from Southeast Asia. Ebaiotrigona Engel & Nguyen, gen. nov., is based on the type species Lisotrigonacarpenteri Engel, recorded from Vietnam, Thailand, Laos, Cambodia, and southern China. The species was previously considered an enigmatic member of Lisotrigona Moure, but is removed to a new genus based on its unique male terminalia that differs considerably from that of Lisotrigona and instead shares resemblances with Austroplebeia Moure, and the presence of yellow maculation (also similar to that of Austroplebeia). It is possible that Ebaiotrigona is the extant sister group of Austroplebeia, but this requires confirmation by future phylogenetic analyses. Based on available biological observations, Ebaiotrigonacarpenteri could not be confirmed as lachryphagous as is well documented from the tear-drinking species of Lisotrigona and Pariotrigona Moure.

First occurrence of the little-known genus Noteriades (Hymenoptera, Megachilidae) from Vietnam: discovery of a new species and a key to the Southeast Asian fauna.

The little-known megachiline genus Noteriades Cockerell, 1931 is recorded from Vietnam for the first time. A new species, Noteriadeshangkia Tran, Engel & Nguyen sp. nov. is described and figured based on a series of females collected from the provinces of the northern and central highlands of Vietnam. The genus is briefly discussed and a new subtribe is established, Noteriadina Engel, Tran & Nguyen subtrib. nov. of Megachilini. Lastly, an identification key and distribution map are provided for those species occurring in Southeast Asia.

Two new species of Trichrysis Lichtenstein (Hymenoptera: Chrysididae) from Vietnam and China, with taxonomic notes on other species from the Oriental region.

Two new species of the genus Trichrysis Lichtenstein, belonging to the cyanea species group, are described from northeastern Vietnam (Cao Bang Province) and China (Yunnan Province) as new for science: T. sinica Rosa, Nguyen & Wisniowski, sp. nov., and T. striata Nguyen, Wisniowski & Rosa, sp. nov. The redescription of T. tonkinensis (Mocsáry, 1914) and additional descriptive characters for T. chamchuensis Wisniowski & Nguyen, 2020 are provided.

Bright green fluorescence of Asian paper wasp nests.

An exceptionally bright fluorescent biomatter was discovered when exploring, with UV-A light, the nests of several oriental paper wasp species of the genus Polistes, a genus of diurnal social insects. Fluorescence spectra of the cocoon cap membranes revealed narrow emission bands in the green range of the visible spectrum. Large Stokes shifts of around 160 nm and high fluorescence quantum yields of up to 35% were measured. Transmission spectra were recorded in order to estimate the contribution of the fluorescence to the visible light transmitted through the cocoon cap membrane. The nest fluorescence of the Vietnamese wasps was compared with a European and an American species. Potential biological functions of these interesting fluorescence properties of the studied biomaterial are discussed. The discovery of this striking example of a fluorescent terrestrial biomaterial may contribute to the debate on adaptive biological functions of natural fluorescence and falls in line with the growing interest in biodiversity and bio-inspiration.

New findings on the taxonomy of the genus Coeleumenes van der Vecht (Hymenoptera: Vespidae: Eumeninae) from Vietnam, with description of a new species.

A new species of the genus Coeleumenes van der Vecht is described from Tay Nguyen highland in southern Vietnam: Coeleumenes chumomray Mai and Nguyen, sp. nov. A key to all known species in the Oriental Region is provided.

Review of Holophris Mocsáry/ (Hymenoptera: Chrysididae) from Vietnam, with description of a new species.

The genus Holophris Mocsáry, 1890 of the tribe Elampini (Chrysidinae) is reviewed in Vietnam for the first time. A new species, H. melinh Nguyen Wisniowski, sp. nov. is described and illustrated, and two species, H. taiwana Tsuneki (1970) and H. thailandica Rosa, Wei, Notton Xu, 2016 are newly recorded. An updated key to all species of the genus known from Oriental region is presented.

Contribution to the genus Pararrhynchium de Saussure (Hymenoptera: Vespidae: Eumeninae), with description of two new species from Vietnam.

Two new species of the genus Pararrhynchium de Saussure are described as new to science: P. simsanum Nguyen and Tran, sp. nov. from Bat Xat, Lao Cai province, and P. sparsum Nguyen and Ljubomirov, sp. nov. from Ham Yen, Tuyen Quang province. An updated key to all known species of the genus is also presented.

Taxonomic notes on the genus Vespa Linnaeus, 1758 (Hymenoptera: Vespidae: Vespinae) from Vietnam, with a new record of a species and an updated key to species.

A taxonomic study on the genus Vespa from Vietnam is presented. One species, Vespa fumida van der Vecht, 1959 is recorded as new for the Vietnamese fauna. The complete queen nest of Vespa mocsaryana du Buysson, 1905 is described, together with the queen. An updated key to all of the Vespa species known from Vietnam based on external morphological characters is also provided.

Taxonomic study on the genus Pseudozumia de Saussure (Hymenoptera: Vespidae: Eumeninae) from Vietnam, with description of a new species.

A taxonomic study on the genus Pseudozumia de Saussure from Vietnam is presented. One species previously identified as Pseudozumia indica indica (de Saussure, 1855) is described as new, namely P. cucphuongensis Nguyen, sp. nov. The second species, P. indica (de Saussure) has two subspecies occurring in Vietnam, P. indica indica (de Saussure) from northern part and P. indica borneana Giordani Soika from southern part which is newly recorded from Vietnam. A key to the Oriental species of the genus is also given.

Additional knowledge respecting taxonomy of the social wasp genus Ropalidia (Hymenoptera: Vespidae: Polistinae) from Vietnam, with new records of three species and an updated key to species.

Species composition of social wasps of the genus Ropalidia from Vietnam is reported, with 24 species having been recorded. Of those, three species are newly recorded for the Vietnamese fauna, namely Ropalidia binghami van der Vecht, 1941, R. parartifex Tan van Achterberg, 2014 and R. variegata (Smith, 1852). The presence of R. sumatrae (Weber, 1801) in Vietnam is confirmed. An updated key to all recorded species of the genus Ropalidia from Vietnam is also provided.

Taxonomic review and distribution of the genus Vespula Thomson, 1869 (Hymenoptera: Vespidae: Vespinae) from Vietnam.

A taxonomic review of the genus Vespula Thomson in Vietnam is reported. Three species are recorded: V. flaviceps (Smith, 1870), V. koreensis (Radoszkowski, 1887), and V. orbata (Buysson, 1902). Of these, V. flaviceps is newly recorded from Vietnam. Distribution records of all three species and an identification key to species based on morphological characters are presented. Vespula koreensis is distributed from high (Cao Bang, Vinh Phuc, Quang Tri) to lower areas (Thai Nguyen, Tuyen Quang, Lang Son, Bac Giang), while the other two species are distributed in high mountainous areas of the northern and central regions of Vietnam such as in Cao Bang, Lao Cai, Son La, Phu Tho, Vinh Phuc, Quang Tri and Quang Nam provinces.

Taxonomic studies on the genus Orancistrocerus van der Vecht, 1963 (Hymenoptera: Vespidae: Eumeninae) from Vietnam, with description of a new species.

Two species of the genus Orancistrocerus van der Vecht, 1963 from Vietnam are recorded. Of them, a new species, O. altus sp. nov. from Lang Son province in the northern part of Vietnam is described and illustrated. In addition, one subspecies, O. aterrimus nigriceps van der Vecht, 1963 is newly recorded from China.

Contribution to the genus Okinawepipona Yamane (Hymenoptera: Vespidae: Eumeninae) from Vietnam, with description of a new species.

A new species of the genus Okinawepipona Yamane from Vietnam is described and figured: Okinawepipona yty Nguyen, sp. nov. (northern Vietnam). Biology of O. yty Nguyen, sp. nov. and O. nigra Nguyen Xu, 2014 is recorded. A key to the four species known in the genus is provided.

Additions to knowledge of the paper wasp Polistes delhiensis Das and Gupta, 1989 (Hymenoptera: Vespidae: Polistinae) from Vietnam with description of the male and nest.

Notes on the paper wasp of the genus Polistes, Polistes delhiensis Das and Gupta, 1989 (Hymenoptera: Vespidae: Polistinae) from Vietnam are presented. The species has two color forms of the clypeus: brightly colored specimens were collected in the southern part of the range and darker colored specimens were collected in the northern part. Based on morphological and DNA data analysis, it is confirmed that both color forms belong to Polistes delhiensis. The male of this species is described for the first time and its fully-developed nest is also described.