A taxonomic study on the genus Zethus Fabricius from Hong Kong, with proposal of a new synonym (Hymenoptera: Vespidae: Eumeninae).

We review three leaf-cutter wasp species of the genus Zethus Fabricius, 1804 occurring in Hong Kong. Zethus malayanus Gusenleitner, 2010, syn. nov. is proposed as a junior synonym of Z. bakeri Giordani Soika, 1995; we clarify the status of Zethus dolosus Bingham, 1897 formerly reported from Hong Kong and add Z. angulatus Nguyen & Carpenter, 2016 as new to Hong Kong. We provide descriptions and high-resolution images for the three species, including male genitalia of Z. angulatus and Z. bakeri.

Evidence for Range Expansion and Origins of an Invasive Hornet Vespa bicolor (Hymenoptera, Vespidae) in Taiwan, with Notes on Its Natural Status.

The invasive alien species (IAS) Vespa bicolor is the first reported hornet that has established in Taiwan and is concerning as they prey on honeybee Apis mellifera, which leads to colony losses and public concerns. Thus, the aim of this study was to assess the current status of V. bicolor abundance, dispersal, and impact and to trace the origins of Taiwan's V. bicolor population. Our studies took place in five areas in northern to central Taiwan. We used mtDNA in the phylogenetic analyses. Field survey and ecological niche modeling (ENM) were used to understand the origins and current range of the invasive species. Two main subgroups of V. bicolor in the phylogenetic tree were found, and a clade with short branch lengths in Southeastern China and Taiwan formed a subgroup, which shows that the Taiwan population may have invaded from a single event. Evidence shows that V. bicolor is not a severe pest to honeybees in the study area; however, using ENM, we predict the rapid dispersion of this species to the cooler and hilly mountain areas of Taiwan. The management of V. bicolor should also involve considering it a local pest to reduce loss by beekeepers and public fear in Taiwan. Our findings highlight how the government, beekeepers, and researchers alike should be aware of the implications of V. bicolor's rapid range expansion in Taiwan, or in other countries.

Flower-visiting insects of genus Melastoma (Myrtales: Melastomataceae) at the Fushan Botanical Garden, Taiwan.

BACKGROUND: We investigated the diversity and behaviour of insects that visit flowers of four native Melastoma (Family Melastomataceae) species of Taiwan and a horticultural hybrid Melastoma species at the Fushan Botanical Garden, Taiwan biweekly from May to August 2020. Visits of flower-visiting insects were classified into seven behavioural categories, based on the insects' behaviour and positions on the flower. The data are further assigned into four insect-flower interactions, namely pollination, herbivory, commensalism and neutralism. Our goal is to provide baseline data of insect-plant interactions of Melastoma, which is a common, but understudied plant genus in the country. NEW INFORMATION: A total of 1,289 visits to flowers were recorded by at least 63 insect morphospecies belonging to seven orders. The number of insect species recorded per Melastoma species ranged from 9 to 39. Visiting, sonication and passing were the three most frequently recorded types of behaviour, collectively accounting for 90.2% (n = 1,240) of the total observations. Pollination was the most dominant insect-flower interaction, accounting for 70.2% of the total observations, followed by neutralism (20.0%), herbivory (6.3%) and commensalism (3.5%). Sweat bees of the genera Lasioglossum and Maculonomia (Hymenoptera: Halictidae) are considered key pollinators to Melastoma species in Fushan Botanical Garden, based on their high number of visits and sonication behaviour. Our study provides the first list of insects that visit the flowers of all Taiwan's known Melastoma species and description of their interactions with the plants.

Variation in Fukienogomphus prometheus (Lieftinck, 1939) reveals Stylurus takashii (Asahina, 1966) as a junior synonym, with discussion on the status of F. choifongae Wilson amp; Tam, 2006 (Odonata: Gomphidae).

We investigate variation of body pattern in Fukienogomphus prometheus (Lieftinck, 1939) and notice the similarity of its female to Stylurus takashii (Asahina, 1966), an enigmatic species whose male is still unknown. We then review the taxonomic history of S. takashii and compare its holotype female with the female F. prometheus. Our results show S. takashii is a junior synonym to F. prometheus. We elucidate the intraspecific variation of F. prometheus and provide information for its ecology and distribution in Taiwan. We also discuss the similarities between the adults of Fukienogomphus choifongae Wilson Tam, 2006 and F. prometheus which in future studies may prove to be conspecific and will require to synonymise the two names. Finally, we confirm the genus Stylurus Needham, 1897 is not distributed in Taiwan.

Description of Sarasaeschna kaoi sp. nov. in Taiwan, with notes on the proposed differentiating characters of the pyanan-group (Odonata, Aeshnidae).

Sarasaeschna kaoi sp. nov. collected from Yuli, Hualien County in eastern Taiwan, is easily distinguished from all known congeners by its male having short and straight cerci. Judging from male penile structure, it is considered to belong to the pyanan-group of species and resembles in general appearance the Chinese S. zhuae described from Fujian. The only known habitat of S. kaoi is a muddy and grassy swamp in natural evergreen forest. The diagnostic characters of the pyanan-group proposed by Karube & Yeh are also discussed.

Establishment of Vespa bicolor in Taiwan (Hymenoptera: Vespidae).

The establishment of a hornet, Vespa bicolor F., in Taiwan was confirmed based on successful field collection of adults of both sexes and two subterranean colonies. Information on nesting habitat, nest measurement, and colony composition of this species are provided in this article. V. bicolor is the ninth hornet species ever recorded from Taiwan. Possible pathway for the introduction of this alien species is also discussed.

Description of a new species of the genus Sarasaeschna Karube & Yeh, with a key to the species of Taiwan (Odonata: Anisoptera: Aeshnidae).

Sarasaeschna chiangchinlii sp. nov. collected from Daxi, Taoyuan County in northern Taiwan is described and diagnosed. Judging from male penile structure, this species is considered to belong to the pryeri-group of its genus. It is easily distinguished from all known congeners in having peculiar sickle-shaped cerci in male. The habitats of S. chiangchinlii are mainly shaded brooks in lowland areas, which are exceptional for its Taiwanese relatives. Distributional maps and a key are also provided for the four species of Taiwanese Sarasaeschna. 

Description of an endemic and endangered new Sympetrum species (Odonata: Libellulidae) from the subtropical area of Taiwan.

Sympetrum nantouensis sp. nov. collected from Nantou, Central Taiwan, is described and figured, with remarks on its ecology and oviposition behaviour. Judging from penile structure, it is considered to belong to the infuscatum-group, whose members are defined here by penile characters. In the infuscatum-group, S. nantouensis is most similar to S. risi Bartenev, but they are probably not very closely related to each other. Sympetrum nantouensis differs from S. risi mainly in having beak-like cerci, well-lineated black and pale yellow pterothorax, and penile 4th segment with longer and apically upcurved cornua. This new species is distinct among its congeners in view of both biogeography and morphology because of its confined and peripheral existence and the odd shape of its cerci. All type specimens will be deposited at the Insect Collection of TFRI.