The structure and antimicrobial potential of wasp and hornet (Vespidae) mastoparans: A review

Wasp venom is a complex mixture of biologically active components, including high molecular weight proteins, small peptides, bioactive amines, and amino acids. Peptides comprise up to 70% of dried venom. In social wasp venoms, three of the major peptide types are mastoparans, which cause mast cell degranulation, chemotactic peptides, which promote chemotaxis of polymorphonucleated leukocytes, and kinin‐related peptides, which are known to produce pain and increase vascular permeability. Among these, the bioactive tridecapeptide mastoparan is the most common and may even have antimicrobial activity. Herein we summarize the results of studies on vespid mastoparans, focusing on hornets (Vespa spp.) identified following a systematic literature search for mastoparans of hornets in the genus Vespa, the most active mastoparan research taxon. The common features of hornet mastoparans are C‐terminal amidation, amphipathic helical structure, and multiple functions such as mast cell degranulation and hemolysis, as well as membrane permeabilization. Most interestingly, all tested hornet mastoparans have strong antimicrobial activities, suggesting that they can provide useful insights into and opportunities for development of novel antibacterial peptides.     

Functional Expression and Characterization of Dipeptidyl Peptidase IV from the Black-Bellied Hornet Vespa basalis in Sf21 Insect Cells

The maturation of mastoparan B, the major toxin peptide in the venom of Vespa basalis, requires enzymatic cleavage of its prosequence presumably via sequential liberation of dipeptides. The putative processing enzyme, dipeptidyl peptidase IV, was expressed as a glycosylated His-tag fusion protein (rDPP-IV) via the baculovirus expression system. rDPP-IV purified by one-step nickel-affinity chromatography was verified by Western blot and LC-MS/MS analysis. The k_cat/K_m of rDPP-IV was determined to be in the range of 10–500 mM^?1·S^?1 for five synthetic substrates. The optimal temperature and pH for rDPP-IV were determined to be 50 °C and pH 9. Enzymatic activity of rDPP-IV was significantly reduced by 80 and 60% in the presence of sitagliptin and phenylmethylsulfonyl fluoride respectively.     

大胡蜂蜂毒中多肽和蛋白质结构和功能的多样性

为证明大胡蜂Vespa magnifica(Smith)蜂毒具有较大的药用开发价值,本研究采用超高效液相色谱-质谱和电泳技术对其多肽和蛋白质的分布进行分析,发现其蛋白质的相对分子质量主要分布在17~45kDa范围内。蜂毒多肽类物质的相对分子质量呈"单峰"式分布,61%在500~3000Da范围内,为大胡蜂蜂毒中多肽含量最为丰富的部分。通过牛津杯法对蜂毒的抑菌活性进行研究,且以HepG2人肝癌细胞及B16黑色素瘤细胞为研究对象,用MTT法检测蜂毒的细胞毒性活性,证明其具有良好的抑菌作用和细胞毒活性,其结果与已报道的其他蜂类既有相似性又存在具体差异,展示了大胡蜂蜂毒的分子多样性,为后续该毒素的物质基础研究及药用价值开发提供参考。     

Do hornets have zombie workers?

Colonies of the European hornet, Vespa crabro, are typically founded by a single queen mated to a single male. From the resulting colony relatedness pattern we predicted strong worker-queen conflict over male production where both the workers and the queen attempt to produce the colony's males. To test for this conflict, male production was studied in 15 hornet nests using a combination of DNA microsatellite analysis (282 males), worker ovary dissections (500 workers from eight nests) and 50 h of observation (four nests). In contrast to our prediction, the data show that hornet males are queens' sons, that workers never attempt to lay eggs, rarely have activated ovaries, and that there is no direct aggression between the queen and the workers. This contrasts with other data for vespine wasps, which support relatedness predictions. Dolichovespula arenaria has the same kin structure as V. crabro and workers produce males in many colonies. The similarity between these two species makes it difficult to explain why workers do not reproduce in V. crabro. Self-restraint is expected if worker reproduction significantly reduces colony productivity but there is no obvious reason why this should be important to V. crabro but not to D. arenaria. Alternatively, queen control may be important. The absence of expressed queen-worker conflict rules out physical control. Indirect pheromonal control is a possibility and is supported by the occurrence of royal courts and queen pheromone in Vespa but not Dolichovespula. Pheromonal queen control is considered evolutionarily unstable, but could result from a queen-worker arms race over reproductive control in which the queen is ahead. The genetic data also revealed diploid males in one colony, the first example in the vespine wasps, and two colonies with double matrilines, suggesting that occasional usurpation by spring queens occurs.     

Do battles lead to coexistence? Role of interference competition in structuring the insect community on fermented tree sap

Abstract.  1. In insect communities on fermented tree sap, agonistic interactions occur frequently among the component species. This study examined the effects of such interference competition on community structure and species co-occurrence on a spatio-temporally small scale.
2. Experimental removal of giant hornets ( Vespa mandarinia ), one of the most dominant species, showed no effect on either species richness or total abundance of the remaining insects. Significant increases in abundance were detected for five out of 19 taxa: V. ducalis , V. crabro , Lasius japonicus , Cryptarcha lewisi , and a group of micro sap beetles ( Epuraea spp., Haptoncus spp., and Haptoncurina spp.).
3. Behavioural observations indicated that interference did not alter the staying time at a patch (an exuding spot on a tree) for V. mandarinia , Rhomborrhina japonica , and Neope goschkevitschii . Interference-mediated departure from a patch was less frequent than departure without interference for all nine species observed, except for R. japonica . These behavioural contexts varied yearly for several species.
4. These results suggest that interference competition is a minor determinant of overall community structure, despite its conspicuousness. This weak effect of interference may be attributed to the short stay of dominant species and to individual behavioural responses, such as competitor avoidance. The variable influence of interference might be related to differences in species attributes, such as dominance hierarchies.     

Behavioral syndrome in a native and an invasive hymenoptera species

Recent studies have focused on the role of behavior in biological invasions. Individuals may differ consistently in time for several behavioral traits (personality) which covary (behavioral syndrome) resulting in different behavioral types, some of them favoring invasion. Social hymenopterans have a strong potential to be invaders and their success depends primarily on the foundresses’ ability to found viable colonies. They are expected to be active, explorative and bold for optimally establishing their nest. In Europe, 2 hornet species coexist: the native Vespa crabro and the invasive Vespa velutina. These 2 species may compete for nesting sites and we suggest that the initial success of V. velutina has been favored by its behavior in outperforming V. crabro for the traits involved in nest initiation. Here, we (i) defined the personality of V. crabro and V. velutina, (ii) tested for the existence of behavioral syndrome in these species, and (iii) compared their performances using an open‐field test. Our results show that V. crabro foundresses behave consistently but not V. velutina; this lack of consistency being mainly due to reduced variance among individuals. This result questions the possibility of detecting consistent behavioral differences in species having recently undergone a strong bottleneck. Both species exhibit the same correlations between activity, boldness and exploration and V. velutina clearly outperforms V. crabro for all traits. Our results suggest that activity, boldness, and exploration are implicated in both hornet nest initiation and invasion process which contributed to explain why social hymenopterans are so successful at colonization.     

Early collapse of Vespa simillima (Hymenoptera, Vespidae) colonies in central Japan

During the past 15 years in the Ina Valley, Japan, mature fifth instar larvae of the yellow hornet, Vespa simillima, have been occasionally ejected from colonies during September. During 2005, this unusual behavior was particularly widespread, and collection of several V. simillima colonies confirmed that very few fifth instar larvae were present. When compared with an average colony, constructed from 41 colonies collected 20 years previously, colonies in 2005 had 80% fewer fifth instar larvae, despite queen egg‐laying rates remaining similar. It may be that the amount of food provided to the larvae by workers is less than the amount of larval secretions received by workers, which is causing the larvae to become emaciated and preventing them from pupating. This phenomenon normally occurs naturally at the end of the colony cycle in November, when prey abundance decreases and larval secretions or other sources of carbohydrates, for example from ripe fruit, tree sap, or aphid secretions, are needed by sexuals to build up fat reserves. However, another possibility is that the unexplained appearance of this phenomenon in September, which is causing colonies to collapse without producing any or very few sexuals, is due to foragers feeding the larvae prey that are contaminated with insect growth regulators, via pesticides, which are known to prevent successful pupation.     

黄蜂胃部表皮黄色颗粒的微观形态与发育(英文)

东方大黄蜂（胡蜂）Vespa orientalis（膜翅目Vespinae属）的胃部表皮黄色颗粒位于黄色条纹区域。从黄色颗粒产生至在这一区域扩散,这个过程就是胃部黄颜色形成的过程。用几种电子显微镜研究了黄色颗粒的微观形态和发育过程。结果显示黄色颗粒由20—25 µm厚的一层组成,包括总表皮在内厚度约为40—45 µm。从上面看,在上述的区域能看到许多直径大约为0.5 µm周边光感受器细胞(PPC)。在每个黄色颗粒,能观察到一个肌样包膜,它位于一个由9根原纤维组装而成的圆圈内部。黄色颗粒成熟的过程包含通过导管的渗透增加初生黄色粒子数量,这些初生粒子又发育或增生成次生粒子,次生粒子逐渐布满整个区域。在这些黄色粒子层内可产生类似于肝的功能活动。     

Evolution of wing shape in hornets: why is the wing venation efficient for species identification?

Wing venation has long been used for insect identification. Lately, the characterization of venation shape using geometric morphometrics has further improved the potential of using the wing for insect identification. However, external factors inducing variation in wing shape could obscure specific differences, preventing accurate discrimination of species in heterogeneous samples. Here, we show that interspecific difference is the main source of wing shape variation within social wasps. We found that a naive clustering of wing shape data from taxonomically and geographically heterogeneous samples of workers returned groups congruent with species. We also confirmed that individuals can be reliably attributed to their genus, species and populations on the basis of their wing shape. Our results suggested that the shape variation reflects the evolutionary history with a potential influence of other factors such as body shape, climate and mimicry selective pressures. However, the high dimensionality of wing shape variation may have prevented absolute convergences between the different species. Wing venation shape is thus a taxonomically relevant marker combining the accuracy of quantitative characters with the specificity required for identification criteria. This marker may also highlight adaptive processes that could help understand the wing's influence on insect flight.     

野牡丹科植物与蜂类某些类群的进化关系初探

本文提出熊蜂、胡蜂等采集野牡丹科植物花粉的现象,进而探讨了野牡丹科植物与熊蜂、胡蜂……等之间的共同进化关系,并指出野牡丹科植物与熊蜂等类群,在系统进化中有平行进化的关系。