To investigate genes differentially expressed in the venom of social and solitary wasps, a comparative transcriptome analysis was conducted. Subtractive expressed sequence tag (EST) libraries specific to the venom gland and sac (gland/sac) of a social wasp species, Vespa tropica and a solitary hunting wasp species, Rhynchium brunneum, was constructed by suppression subtractive hybridization. In BLASTx analysis, 41% and 56% of the total ESTs showed statistically best-matched hits (E ≤ 10-4) in the libraries of V. tropica and R. brunneum, respectively. Although the functional category analysis did not show remarkable differences in the distribution of functional categories between the two venom gland/sac cDNA libraries, perhaps due to the lack of functional information on many of the venom components, there were groups of genes that are specific to either V. tropica or R. brunneum. Venom allergen 5 and serine protease were found to be social wasp-specific venom transcripts. In contrast, venom peptides, metalloendopeptidases, arginine kinase and dendrotoxin were observed in solitary wasp at much higher frequencies.

The highabundance and impact on honeybees of the Asian hornet Vespa velutina var. nigrithorax have caused great concern among European public authorities and beekeepers. The species was reported for the first time in France in 2005 and spread out across 66 European districts (ca. 360 000 km 2 ) within 7 years (INPN, 2012; Rome et al., 2013). Its arrival was reported in 2010 in Northern Spain, in 2011 in Portugal and Belgium and in 2013 in Italy. Its wider expansion in Europe is soon to be expected. We discuss here the advances of the collaborative research project initiated in 2008 in France. 1. The potential invasion risk of the species was assessed using modeling tools of climatic suitability (Villemant et al., 2011, Barbet-Massin et al., 2013). Interestingly, the potential distribution of V. v. nigrithorax matches the current distribution of another invasive social wasp, the German yellow jacket, Vespula germanica (Beggs et al., 2011). 2. Apartfrom reported damages on hives, little is known on the biology of V. velutina throughout its native Asian range. In the invaded range, the impact of V. v. nigrithorax on the diversity and biomass of the invertebrate fauna is under study. Preliminary results reported a diversified diet varying among seasons and habitat types. 3. The genetic variability between individuals of V. v. nigrithorax from France and Asia was assessed in order to describe the history of its invasion. The analysis has evidenced a low variability among the invasive population, which indicates a single introduction of one or more queens. The sampling of specimens in France and in the area of origin has been extended to confirm this hypothesis and the most probable area of origin (Arca, 2012). Given the potential economic and biological impact of V. v. nigrithorax, a better understanding of its invasion dynamics is necessary to predict regions at risk, hence to help with planning dedicated control measures, a prerequisite for replacing the reactive nature of current solutions with a proactive, predictive approach.

Invasive hornet Vespa velutina nigrithorax, which was found at Yeongdo, Busan for the first time in 2003, has been spreading to whole area of Gyeongnam and even to some southern parts of Gyeongbuk for last ten years, causing lots of damage. Urban area of Busan already showed dominant distribution of V. v. nigrithorax marking more than 90% of emergence rate by its spread, while in forest area, its rate had not been so high due to its competition with native Vespa species. However, recently dominance of this species was detected continuously in some forests in Busan. Thus, this study conducted a survey of emergence rate of V. v. nigrithorax at Mt. Bongraesan, Yeongdo-gu, Busan where it was discovered for the first time and also conducted observation of its behaviors related with competition for prey in order to understand its ecological niche relation with native Vespa species. Consequently, 4,560 individuals were collected in total out of main five species of Vespa at Mt. Bongraesan. Of these, V. mandarinia made up 8.7% with 397, V. crabro flavofasciata 21.2% with 965, V. analis parallela 23% with 1,048, V. simillima simillima 0.6% with 27, while V. v. nigrithorax made up 46.6% with 2,123, demonstrating the aspect of the most dominant emergence of V. v. nigrithorax. On the other hand, ecological niche due to competition for prey between V. v. nigrithorax and native Vespa species was revealed in the order of V. mandarinia >> V. crabro flavofasciata > V. analis parallela ≥ V. v. nigrithorax, telling ecological niche of V. v. nigrithorax was relatively low compared to native Vespa species, despite its dominant emergence. This background may explain why in forest area, V. v. nigrithorax had a limited spread and dominance compared to urban area of less competition among Vespa species. On the other hand, V. v. nigrithorax seems to have advantage in catching small insects due to developed agility with its smaller size than other Vespa species, and its rapid spread and adaptation in the local environment may be mainly attributable to its far more number of individuals than native Vespa species and consequent high reproductive rates and diversity of nesting site.

Biological invasion is becoming more important disturbance factor to the structure and function of ecosystem as well as to the bio-industry such as apiculture. Since the invasion of the yellow-legged hornet, Vespa velutina nigrithorax Buysson, 1905 into Busan port, the southeastern part of Korea in 2003, gradual spread of the hornet was observed. The rate of spread was estimated as 12.4 Km/yr, which was 5.6 times slower than that from France, 67.3 Km/yr. The diffusion coefficient (D) is still in increasing phase, implying the greater risk of spread. The Korean population was homologous to Zhejiang population of China implying the possible invasion source. It has a great potential to harm the Korean beekeeping industry and the ecosystem through the competition with the similar guild, the other 10 spcies of Vespa in Korea. Among those, smaller sized hornets such as Vespa analis or V. simillima simillam seemed under serious impact. Community structure of Vespa was different before and after the invasion. After V. velutina invasion, the survey on 2010 from Gyeongnam province showed 67% of V. velutina and reduced proportion of the smaller size hornets such as V. analis, V. crabro and V. simillima simillima compared to the bigger sized hornets such as V. mandarinia or V. ducalis. Also because of the nesting urban area, public education and involvement are requested for protection against the hornet’s aggresiveness and also for monitoring the distribution and population expansion. Further research and public network would mitigate the potential risks.

Many animals are capable of detecting sensory information emitted by predators. When predation risk is high, orb-web building spiders should change its foraging strategy of the web construction. We examined web building behaviors of an orb-web spider, Argiope bruennichi providing sensory information of its predator, a yellow hornet, Vespa simillima. We observed web characteristics after providing sensory information of the yellow hornet (experimental group; N=29) and compared to the control group (no information provided; N=34). We hypothesized that the spiders in the experimental group would decrease investments in its web construction and stabilimentum decoration to avoid being located by the predator. The results rejected our hypothesis. Web and stabilimentum constructions decreased in the course of the experiment in both control group and experimental group. But the differences between control group and experimental group were not significant. The individuals did not reduce its stabilimentum length and did not decrease its web area in spite of sensory information of the predator.

Vespa tropica is a tropical species of Vespa found in Southeast Asia. V. tropica wasps were collected from rural provinces of Cambodia, and their total RNA and venom were extracted on site. To search for novel substances in venom, a subtracted cDNA library specific to the venom gland and sac was constructed and venom protein was analyzed by nano-LC-MS/MS. A total of 1127 expressed sequenced sequence tags (ESTs) were sequenced and assembled into 572 contigs (152 multiple sequences and 420 singletons). The short venom peptides were identified to be encoded from 5 contigs (43 ESTs) by proteomic analysis. In addition, putative antimicrobial peptides together with typical major components of wasp venom (venom allergen 5, mastoparan-like peptide, serine protease, and hyaluronidase) were identified in the EST Library. Additional in-depth annotation would be required for further characterization of many unidentified genes found in the EST library.