Confirmation of the valid specific status of Dolichovespulakuami Kim & Yoon, 1996 (Hymenoptera, Vespidae) based on molecular and morphological evidence.

The taxonomic validity of Dolichovespulakuami, especially in relation to D.flora, has been the subject of a long-term debate. Herein, the valid specific status of the former was supported through an integrated analysis of morphological characters and DNA barcodes. The pronotal rugae and male genitalia of the two species are different, and partial mitochondrial genes (cytochrome oxidase subunit I, COI) indicate that they form significantly distinct lineages. The hitherto unknown male of D.kuami is described for the first time, and a brief discussion of the D.maculata species group is provided.

Gut bacterial diversity in Vespa velutina and implications for potential adaptation in South Korea.

BACKGROUND: Invasive species such as the yellow-legged hornet (Vespa velutina), along with four other Vespa species - Vespa analis, Vespa crabro, Vespa ducalis, and Vespa mandarinia - pose significant threats to the environment, economy, and human health. This study focuses on understanding the key factors contributing to the successful invasion of these species, particularly V. velutina, in South Korea. The analysis encompasses the gut bacterial communities and stable isotopes of carbon and nitrogen of the queen hornets, aiming to identify variances in gut microbial composition and food resource utilization. RESULTS: The gut bacterial communities in the five Vespa species were primarily composed of Proteobacteria, with Firmicutes and Bacteroidetes present. Vespa velutina and V. mandarinia had higher Firmicutes abundance at the phylum level, possibly indicating an increased capacity for dietary fiber breakdown and short-chain fatty acid production, providing them with a competitive edge. No significant differences in nitrogen and carbon stable isotope values were found among the five Vespa species, suggesting that they fed on similar food sources. However, V. velutina had a higher number of unique gut bacterial operational taxonomic units (OTUs), implying adaptation through the acquisition of a distinct gut bacterial set. Significant correlations were found between the observed index and the Shannon index, and between δ15 N and the observed index, suggesting that the food source diversity may influence the gut bacterial community diversity. CONCLUSION: Our study offered valuable insights regarding the adaptation of V. velutina to its new environment in South Korea. The potential role of gut microbiota in the success of invasive species was elucidated. This information is crucial for the management of invasive species, targeted control methods, and implementing preventive regulations. Further studies with larger sample sizes and comprehensive sampling are required to gain a complete understanding of the gut microbiota of Vespa species and their adaptation to new environments. © 2023 Society of Chemical Industry.

Long-Term Administration of Vespa velutina nigrithorax Venom Ameliorates Alzheimer's Phenotypes in 5xFAD Transgenic Mice.

Alzheimer's disease (AD), the most prevalent neurodegenerative disease, is characterized by progressive and irreversible impairment of cognitive functions. However, its etiology is poorly understood, and therapeutic interventions are limited. Our preliminary study revealed that wasp venom (WV) from Vespa velutina nigrithorax can prevent lipopolysaccharide-induced inflammatory signaling, which is strongly implicated in AD pathogenesis. Therefore, we examined whether WV administration can ameliorate major AD phenotypes in the 5xFAD transgenic mouse model. Adult 5xFAD transgenic mice (6.5 months of age) were treated with WV by intraperitoneal injection at 250 or 400 µg/kg body weight once weekly for 14 consecutive weeks. This administration regimen improved procedural, spatial, and working memory deficits as assessed by the passive avoidance, Morris water maze, and Y-maze tasks, respectively. It also attenuated histological damage and amyloid-beta plaque formation in the hippocampal region and decreased expression levels of pro-inflammatory factors in the hippocampus and cerebrum, while it reduced oxidative stress markers (malondialdehyde in the brain and liver and 8-hydroxy-2'-deoxyguanosine in the plasma). Overall, these findings suggest that long-term administration of WV may alleviate AD-related symptoms and pathological phenotypes.

Nidus vespae Built by an Invasive Alien Hornet, Vespa velutina nigrithorax, Inhibits Adipose Tissue Expansion in High-Fat Diet-Induced Obese Mice

Nidus vespae, commonly known as the wasp nest, has antioxidative, anti-inflammatory, antimicrobial, and antitumor properties. However, the anti-obesity effects of Nidus vespae extract (NV) have not yet been reported. This study aimed to elucidate the potential anti-obesity effects of NV in vivo and in vitro, using a high-fat diet (HFD)-induced obese mouse model and 3T3-L1 adipocytes, respectively. NV administration to HFD-induced obese mice significantly decreased the mass and plasma lipid content of adipose tissues. Uncoupling protein-1 expression was significantly higher in the inguinal white adipose tissues of NV-treated mice than in those of HFD-fed mice. Furthermore, we found that NV inhibited the differentiation and intracellular lipid accumulation of 3T3-L1 adipocytes by regulating the insulin signaling cascade, including protein kinase B, peroxisome proliferator-activated receptor gamma, CCAAT/enhancer binding protein alpha, and adiponectin. These findings suggest that NV may exhibit therapeutic effects against obesity by suppressing adipose tissue expansion and preadipocyte differentiation, thereby providing critical information for the development of new drugs for disease prevention and treatment. To our knowledge, this study provides the first evidence of the anti-obesity effects of NV.

Genetic and morphological variation of Vespa velutina nigrithorax which is an invasive species in a mountainous area.

The yellow-legged hornet (Vespa velutina nigrithorax) is an invasive species in South Korea with negative economic, ecological, and public health impacts. We investigated genetic and morphological variation in the species populations on Mt. Jiri, the tallest mountain in South Korea. We hypothesized that a high-altitude would be negatively correlated with the genetic diversity of the hornet population, and hornet wing morphology would change with an increase in altitude. Our results showed that the genetic diversity of yellow-legged hornets did not decrease as altitude increased. Regardless of the altitude, the inbreeding coefficient was high at the newly colonized sites. A single genetic population occurred in the mountainous areas examined and gradually expanded its range. Wing morphology, especially shape, did not change with an increase in altitude or decrease in temperature. Although snow cover and cool temperatures at high altitudes could limit nest-building activities, they did not prevent the extension of the range of the species. Therefore, the yellow-legged hornet cannot be controlled naturally by climate or topography; combined approaches, including chemical control, nest removal, and bait-trapping techniques should be implemented.

First Discovery of Vespa velutina nigrithorax du Buysson (Hymenoptera: Vespidae), an Invasive Hornet in the Feces of the Yellow-Throated Marten in South Korea.

Yellow-throated martens (YTMs) are omnivores that often prey on wasps in late autumn in Korea. However, to the best of our knowledge, predation of the invasive alien species Vespa velutina nigrithorax (VVN) has not previously been investigated. In this study, YTM feces were collected and analyzed from Mt. Onggangsan, Sinwon-ri, Cheongdo, South Korea, where VVN density was high and YTMs were active. Surveys were conducted three times between October and December 2019, during which a total of 22 samples were collected. Debris from VVN was found in three samples, along with evidence of two indigenous wasps, Vespa crabro and Vespula koreensis. The VVN remains were identified as one queen, four males, one female, and one individual whose caste was unclear. Martens prey on wasps, owing to a sudden decrease in plant food sources from late autumn to early winter, mostly eating males and new queens attempting to mate. If VVN reproduction is prevented or disturbed by YTM predation, there may be potential biological control effects in areas with high VVN density. Further studies should be conducted to verify whether there is a practical biological control effect.

Defensive behavior of the invasive alien hornet, Vespa velutina, against color, hair and auditory stimuli of potential aggressors.

BACKGROUND: During recent years, invasion of the yellow-legged hornet (Vespa velutina) has occurred in Europe, Korea and Japan, and stinging accidents often occur as some V. velutina nests are in places where humans can reach them. Misleading information regarding precautionary measures for mitigating wasp attacks has only exacerbated the situation. In this study, we sought to identify appropriate countermeasures by analyzing wasp defensive behavior, with a focus on color, hair and auditory stimuli. METHODS: Defensive behavior was analyzed using video recordings by creating an experimental frame to attach experimental bundles to nine V. velutina nests in Daegu and Gyeongbuk, South Korea. For the color experiment, eight-color and single-color tests were conducted with bundles of eight colors (black, brown, yellow, green, orange, gray, red and white), and the difference in defensive behavior was tested between black hair/hairless and green hair/black hairless configurations. RESULTS: When presented simultaneously with bundles of eight different colors, V. velutina showed the greatest and the longest defensive behavior against the black bundle, followed by brown. A similar response was observed in single-color tests. Furthermore, there was no significant difference in the defensive behavior against black hair and black hairless, but the duration of defensive behavior was longer for black hair. A comparison between green hair and black hairless stimuli indicated that wasps are more sensitive to color than to hair texture. Vespa velutina showed no discernible responses when exposed to selected auditory stimuli (human conversation and loud music). Dark colors and dark hair are characteristic features of potential predators, to which wasps are evolutionarily predisposed, and are accordingly likely to provoke strong defensive responses. The results of this study provide scientifically credible information that can be used to base appropriate precautionary measures against wasp attacks.

Interspecific hierarchies from aggressiveness and body size among the invasive alien hornet, Vespa velutina nigrithorax, and five native hornets in South Korea.

The range of the invasive alien hornet, Vespa velutina nigrithorax, has been expanding since its introduction to Korea in 2003. Here, we compare the aggressive behaviors and body size of V. velutina nigrithorax with five native hornet species to identify the interspecific hierarchies that influence the rate of spread of this species. Aggressive behaviors were classified into 11 categories, and each interaction was scored as a win, loss, or tie. We found that V. velutina was superior to V. simillima in fights that V. velutina won and showed a high incidence of threatening behavior. V. mandarinia outperformed V. velutina in fights that V. mandarinia won and grappling behavior was common. V. analis was superior to V. velutina in fights that V. analis won and showed a high degree of threatening behavior. V. crabro was superior to V. velutina in fights that V. crabro won and showed a high rate of threatening behavior. V. dybowskii was superior to V. velutina in fights that V. dybowskii won and showed a high incidence of threatening and grappling behaviors. The body size of V. velutina was greater than V. simillima (although not statistically significant) and smaller than all other Vespa species. Therefore, according to this study, the low interspecific hierarchies of V. velutina seem to be a major cause of the slower spread in Korea than in Europe. However, over time, its density has gradually increased within the forest, where it seems to be overcoming its disadvantages and expanding its range, possibly because the large colonies and good flying abilities of this species help it secure food.

Nutritional Value of the Larvae of the Alien Invasive Wasp Vespa velutina nigrithorax and Amino Acid Composition of the Larval Saliva.

The systematic investigations on the value of social wasps as a food resource are deficient, in spite of the long history of the utilization of social wasps as food and pharmaceutical bioresources. Vespa velutina nigrithorax is an invasive alien wasp species that is currently dominating in East Asia and Europe, bringing huge economic damages. As a control over alien species is made when the valuable utilization of the invasive species as a potential resource are discovered, investigations on the potential of V. v. nigrithorax as a useful bioresource are also in demand. Nutritional and heavy metal analyses of the larvae revealed their balanced and rich nutritional value and safety as a food resource. The larval saliva amino acid composition was investigated for further study on amino acid supplementation and exercise enhancement.

Abundance of diet-derived polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in the bodies and nests of the yellow-legged hornet Vespa velutina nigrithorax and risks to human health in South Korea.

Detecting polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in an organism's environment is ecologically significant. In particular, the detection of PCDD/Fs in organisms consumed as food suggests the possibility of human health risks. In South Korea, there is a unique custom in which social wasps, such as hornets, have been used as ingredients in traditional liquor. Thus, we investigated the concentrations and patterns of PCDD/Fs for the most common social wasps, the yellow-legged hornet (Vespa velutina nigrithorax), and estimated human health risks based on potential dietary exposure in traditional liquor made from the polluted wasps and their nests. The mean concentration of ∑17 PCDD/Fs in the wasps and nests of V. v. nigrithorax was 33.59 pg/g (median 25.31 pg/g), corresponding to 0.65 pg World Health Organization - Toxic equivalency factor (WHO-TEQ/g) (median 0.49 pg WHO-TEQ/g). The levels of ∑17 PCDD/Fs from the nests of V. v. nigrithorax were higher than those in the adults and larvae. As a result of this risk assessment, the daily intake of traditional liquor made with these wasps and their nests was found to be below safety levels; however, there could still be a possibility for health risks due to the detection of PCDD/Fs from organism. Therefore, continuous monitoring of environmental contaminants, including PCDD/Fs in wasps and nests, is required in order to evaluate human health risks associated with the consumption of traditional liquor made with these biological substances. In addition, the results of this study can be used to calculate dietary exposure to PCDD/Fs and the extent of risk to food in which the organism is consumed.

The mitochondrial genome of a social wasp, Vespa simillima simillima (Hymenoptera: Vespidae).

We analyzed the complete mitochondrial genome of a social wasp, Vespa simillima simillima from South Korea prior to a systematic study on Korean Vespidae. The mitogenome is 16,740 bp in length, includes 13 protein-coding genes (PCGs), 22 tRNAs, 2 rRNAs, and a 228 bp short A + T-rich region. The overall base composition is 82.0% AT and 18.0% GC. The maximum-likelihood analysis suggested that V. s. simillima is closely related to V. bicolor, another species of Vespidae.

Recent Trends in Wasp Nest Removal and Hymenoptera Stings in South Korea.

To better understand the impact of social wasps on the health of people in South Korea, we analyzed requests to emergency services call centers for the removal of social wasp nests and the effect of Hymenoptera stings on human health between 2010 and 2014. There were 483,233 calls requesting removal of wasp nests and Hymenoptera stings caused 78,860 injuries and 49 deaths. The strong relationships between both the number of emergency calls and injuries, and urban density reflect the sensitivity of densely populated areas to potential threats from wasp and the increased awareness of the wasp nest removal service communicated by public education programs. We found that the removed nests belonged to 17 species of social wasp, with Polistes rothneyi koreanus Vecht and Vespa velutina nigrithorax du Buysson being the most prevalent. Problems associated with the invasive V. v. nigrithorax increased as the species became more widely distributed across the country and more abundant in urban areas. Increases in the incidence of sting injuries among males aged 40-69 between July and September were likely due to increased exposure during outdoor activities involving less-fit adults. In total, 1.5% of victims required hospitalization, of which 98.5% were treated as outpatients. Total medical costs associated with wasp stings over the 5-yr period were approximately 3.2 million USD. Although most wasp sting-related injuries were minor, some were serious, including fatalities, and were probably attributable to lack of education on wasp attack behavior.