Temporal polyethism in Korean yellowjacket foragers,Vespula koreensis (Hymenoptera,Vespidae)

We examined the foraging behavior of the Korean yellowjacket, Vespula koreensis, to determine whether this species displays temporal polyethism. Using video-recordings of the entrances of artificial nest boxes installed in the field, we investigated the association between the tasks performed by workers and age. We identified three foraging tasks (pulp, nectar and prey foraging). Pulp foraging was performed by younger foragers, while nectar and prey foraging were performed by older foragers. We measured the foraging time (time spent outside of the nest during a single foraging bout) and the weight of the materials that foragers brought into the nest for each task to estimate the cost of the task. Pulp foraging was less costly than nectar or prey foraging by both measures. Taken together, the results suggest that yellowjacket foragers tend to perform low-cost task in their early foraging days and high-cost task later. Our results add to a growing literature showing temporal polyethism in social insects.     

Temperature and forager body size affect carbohydrate collection in German yellowjackets, Vespula germanica (Hymenoptera, Vespidae)

The classic formulation of optimal foraging theory predicts that a central-place forager will gather more food if it is required to travel farther from the nest to find that food. We examined the foraging behavior of German yellowjackets (Vespula germanica) to determine whether carbohydrate foragers follow this pattern. We trained foragers to collect 2 M fructose solution at 5 or 50 m from the nest and measured the time spent feeding, load size, and the rate of delivery. We show that as a forager’s crop fills during a foraging bout, the amount of solution ingested per second decreased. However, load size did not change as wasps collected food up to 50 m from the nest. Instead, temperature and body size were better predictors of the volume of fructose a forager carried. Finally, the rate of fructose delivered to the nest was higher at warmer temperatures. Due to the fact that wasps gather more food but feed for shorter periods of time at warmer temperatures, we found an overall negative relationship between feeding time and load size. We conclude that the strong effects temperature had on the behavior of V. germanica foragers imply that feeding time may not always be an accurate predictor of the size of the load an individual carries back to the nest. Results from this study suggest that in yellowjacket colonies, foragers can collect and bring disproportionately more food back to the nest during the warmest days of the summer, a time of year when this pest species reaches peak population size during its annual colony cycle.     

Relationship between body size and flying-related structures in Neotropical social wasps (Polistinae,Vespidae, Hymenoptera)

Body size influences wing shape and associated muscles in flying animals which is a conspicuous phenomenon in insects, given their wide range in body size. Despite the significance of this, to date, no detailed study has been conducted across a group of species with similar biology allowing a look at specific relationship between body size and flying structures. Neotropical social vespids are a model group to study this problem as they are strong predators that rely heavily on flight while exhibiting a wide range in body size. In this paper we describe the variation in both wing shape, as wing planform, and mesosoma muscle size along the body size gradient of the Neotropical social wasps and discuss the potential factors affecting these changes. Analyses of 56 species were conducted using geometric morphometrics for the wings and lineal morphometrics for the body; independent contrast method regressions were used to correct for the phylogenetic effect. Smaller vespid species exhibit rounded wings, veins that are more concentrated in the proximal region, larger stigmata and the mesosoma is proportionally larger than in larger species. Meanwhile, larger species have more elongated wings, more distally extended venation, smaller stigmata and a proportionally smaller mesosoma. The differences in wing shape and other traits could be related to differences in flight demands caused by smaller and larger body sizes. Species around the extremes of body size distribution may invest more in flight muscle mass than species of intermediate sizes.     

Queen brood reared in worker cells by the social wasp,Vespula germanica (F.) (Hymenoptera: Vespidae)

Summary The rearing of queen brood from worker cells in the nests ofVespula germanica (F.) in Australia was found at all stages of the colony cycle from early summer to autumn. Worker cells used to rear queens were 17% wider at their open ends than cells used for worker production, and in all other respects their dimensions were greater. The volume of a worker cell used for queen nearing was 21% larger than cells used for rearing workers but half the volume of a normal queen cell. Queen pupae reared in worker cells were significantly smaller than those reared in queen cells of the same nest. The spatial distribution of queen pupae in worker comb tended to be random although some evidence of nonrandom clustering was noted.The significance of this phenomenon is discussed in relation to caste differentiation and queen-control of gyne initiation and production. It is concluded that the phenomenon is neither seasonal nor due to some intrinsic component of the colony's annual cycle, and that it is unlikely to be an emergency queen-rearing response. Development of queens in worker cells may have occurred during favourable feeding regimes, perhaps determined by the benign Australian environment.     

Attraction of Vespula germanica (Hymenoptera: Vespidae) foragers by conspecific heads

The socialwasp Vespula germanica (F.) is a serious pest in many regions it has invaded. Control programs to reduce its populations are commonly based on the use of poison baits. These baits also attract nonpestiferous invertebrates and vertebrates. In this work we studied the attraction of V. germanica foragers by conspecific worker squashes, comparing the effect of head and abdomen squashes in wasps behavior. We found that head squashes attract V. germanica foragers, elicit landing and transportation to nests. Furthermore, the addition of squashed heads to a protein bait increased attraction. This could be an alternative to improve baiting programs.     

Dispersal behavior of yellowjacket (Vespula germanica) queens

Understanding the factors that affect animal dispersal behavior is important from both fundamental and applied perspectives. Dispersal can have clear evolutionary and ecological consequences, but for nonnative insect pests, dispersal capacity can also help to explain invasion success. Vespula germanica is a social wasp that, in the last century, has successfully invaded several regions of the world, showing one of the highest spread rates reported for a nonnative insect. In contrast with nonsocial wasps, in social species, queens are responsible for population redistribution and spread, as workers are sterile. For V. germanica, it has been observed that queen flight is limited to 2 distinct periods: early autumn, when new queens leave the nest to mate and find sheltered places in which to hibernate, and spring when new colonies are founded. Our aim was to study the flight behavior of V. germanica queens by focusing on the different periods in which dispersal occurs, characterizing as well the potential contribution of queen flight (i.e., distance) to the observed geographical spread. Our results suggest that the distances flown by nonoverwintered queens is greater than that flown by overwintered individuals, suggesting that the main queen dispersal events would occur before queens enter hibernation. This could relate to a behavioral trait of the queens to avoid the inbreeding with related drones. Additionally, given the short distances flown and remarkable geographical spread observed, we provide evidence showing that queen dispersal by flight is likely to contribute proportionately less to population spread than human‐aided factors.     

云南贡山黄胡蜂属一新种(膜翅目:胡蜂科)

报道云南贡山黄胡蜂属Vespula 1新种,即贡山黄胡蜂Vespula gongshanensis,sp nov．。模式标本保存在中国科学院昆明动物研究所。     

Overwintering colonies of German (Vespula germanica) and common wasps (Vespula vulgaris) (Hymenoptera: Vespidae) in New Zealand

Abstract

Nests of both common (Vespula vulgaris) and German wasps (V. germanica) sometimes overwinter in New Zealand. Three overwintering common wasp colonies were found in low-altitude honeydew beech forest; about 2% of the colonies initiated there in 1988 survived the winter. Wasp traffic rates from nests in Nelson city and a nation wide survey of wasp abundance, showed that more German wasp than common wasp workers were on the wing in winter and spring. German wasp colonies in Nelson city were more likely to overwinter than were common wasp colonies. Of the active German wasp colonies recorded in Nelson in January and February 1989, only two (4%) had previously overwintered, but these two nests accounted for 38% of all German wasp workers estimated to leave nests in the area. Had other overwintering colonies not been poisoned, overwintering colonies might have accounted for up to 11 % of nests and produced up to 64% of German wasp workers on the wing in January and February 1989.

Overwintering common wasp colonies did not produce queens or drones in their first year or second spring, but all 10 overwintering German wasp colonies examined produced sexuals at both times. German wasp queens produced in winter and spring may influence the number of colonies successfully initiated and affect the population dynamics of German wasps in New Zealand.     

How behavioral plasticity enables foraging under changing environmental conditions in the social wasp Vespula germanica(Hymenoptera:Vespidae)

The foraging strategy at abundant resources of the social wasp Vespula germanica includes scanning in the direction of the nest while memorizing resource-specific landmarks and contextual cues.In the present study,we sought to explore wasps'behavioral plasticity on foraging trips to resources whose location and composition changed after a single visit.We evaluated how contextual modifications of food displacement and replacements 60 cm apart from the original site,affect re-orientation for re-finding previously memorized food resources.The results showed that wasps detected and collected the resource faster when more changes were introduced on the following visit.If returning foragers discovered several modifications on both the location and the kind of resource,they collected food more rapidly from the displaced dish,than if only a single parameter in the environment had been changed.These findings illustrate the grade of behavioral plasticity in V.germanica while foraging on abundant resources,which may contribute to the understanding of the prodigious invasive success of this species in anthropized environments.     

Occurrence of the common wasp,Vespula vulgaris (L.) (Hymenoptera: Vespidae) in New Zealand

Abstract

After occurring sporadically in New Zealand since 1921, the common wasp, Vespula vulgaris (L.), was found in March and April 1983 to be established in Dunedin, where 6 nests were discovered. Subsequent examination of museum specimens showed that queens had been collected in Wellington in 1978, and nests by January 1982. Christchurch was invaded in early 1984, several workers were collected near Auckland in March and April 1984, and workers were reported at Nelson in March and May 1984. The Dunedin nests were up to 6 times the size of nests recorded from the Northern Hemisphere, and produced up to 23 times as many new queens. Workers, nest size, and nest productivity were sufficiently different from those reported in western North America to suggest that the New Zealand population originated elsewhere. Colour patterning of the head and pronotum readily separate New Zealand V. vulgaris from New Zealand V. germanica. The nest carton of V. vulgaris is brown; that of V. germanica is grey. Conditions in New Zealand appear to be favourable for V. vulgaris; it can be expected to spread and it may at times reach the high population levels experienced in Europe and the western United States.     

Olfactory Learning of Fruit Odors in the Eastern Yellow Jacket, Vespula maculifrons (Hymenoptera: Vespidae)

Food-seaching workers of eastern yellow jackets, Vespula maculifrons, are attracted by the natural odors of a wide variety of succulent fruits; particularly effective was pear. The only part of a fruit that repelled was the leathery epicarp of oranges. After rewarding with sugar water, odors of six fruits, including the pulpy mesocarp of oranges and, in addition, the leaves of catmint Nepeta cataria, all become highly attractive. To learn the distinctive odors of any one of three fruits (pear, apple, quince), nondiscrimination training with a rewarded fruit was sufficient for the subsequent olfactory preference of the training fruit over the control fruit. In the other cases [banana, hawthorn (Crataegus crus-galli), grape] simultaneous discrimination training with a rewarded and an unrewarded fruit was necessary and effective for obtaining differential responses to the odors of the training fruits. As far as current evidence goes, olfactory learning plays similar roles in the fruit foraging of this wasp and in the nectar foraging of the honey bee (Apis mellifera).     

Field preferences of the Social Wasp Vespula germanica (Hymenoptera: Vespidae) for Protein-rich Baits

Food preferences displayed by foraging insects are important from a fundamental perspective and in pest control. We studied the preference of an invasive wasp, V. germanica, for protein foods in field conditions. Preferences were evaluated by placing baits in a paired design in different habitats and analyzing wasp visits, using a Bayesian approach to the Thurstone model. V. germanica workers display a clear rating of preferences, but were affected by the presence of competitors at the bait. These results contribute knowledge aimed at toxic baiting protocols for this wasp and suggest that food choice is a complex process subject to the influence of diverse factors. We emphasize the importance of on-site paired comparisons in preference studies to fully understand the drivers of food choice by insects.     

Successful and unsuccessful development of colonies of Vespula vulgaris (Linn.) (Hymenoptera: Vespidae)

Abstract.

• 1 Six categories of immature and five categories of mature colonies are described and their developmental relationships suggested.
• 2 Mature brood destroyed by the workers became numerous in 46.4% of the immature colonies. Most of these formed unsuccessful colonies (36.9%) producing few or no queens. The remaining 9.5% recovered to form successful colonies.
• 3 Successful colonies either reared queens only (mean 356 queens), or queens (mean 1461) and males (mean 254) in their large cells.
• 4 The number of small cells in mature colonies correlated with the number of cells built by the founder queen.
• 5 The greater the number of large cells in a mature colony the greater were the chances that a larger proportion of these cells would be used to rear adults.
• 6 The number of small and large cells are correlated in mature successful colonies.
• 7 Queen activity and quality are important factors in the control of colony size and success.
• 8 Selective destruction of male sealed brood in the large cells is linked to worker, rather than queen, control.

     

Ecological features of exotic Vespula wasps (Hymenoptera: Vespidae) invading the southernmost UNESCO Biosphere Reserve

Biological Invasions - Invasive alien species may cause substantial changes and damaging impacts. Here, we document the current distribution and ecological interactions with native biota of...     

Structure of ovarioles in adult queens and workers of the common wasp, Vespula germanica (Hymenoptera: Vespidae)

The ovaries of the common wasp, Vespula germanica are polytrophic-meroistic and consist of 2-3 (workers) or 7 (queens) ovarioles. The ovarioles are differentiated into three regions: a terminal filament, a germarium, and a vitellarium. The germaria of both castes consist of two zones: an anterior zone of germ-cell cluster formation and a posterior one of germ-cell cluster differentiation. The vitellaria comprise 4-6 (workers) or 7-10 (queens) ovarian follicles (egg chambers). Each chamber consists of an oocyte and about 60 isodiametric nurse cells (trophocytes). The egg chambers have been arbitrarily classified into four developmental categories: early and late previtellogenic, vitellogenic, and choriogenic. The process of oogenesis in workers proceeds only up to the onset of the late previtellogenesis. Neither vitellogenic nor choriogenic egg chambers were observed in this caste. During early and late previtellogenesis the envelope of the oocyte nucleus proliferates and becomes highly folded. This process leads to the formation of characteristic organelles, termed accessory nuclei (AN). Although AN arise in the oocytes of both queens and workers, their number in the latter caste is always considerably lower. At the onset of the late previtellogenesis AN start to migrate towards the periphery of the oocyte where they reside till the end of oogenesis. The physiological state of the worker ovaries is discussed in the light of the presented results.     

The origin and evolution of social life in the Stenogastrinae (Hymenoptera,Vespidae)

The Stenogastrinae are a subfamily of the Vespidae. The main difference between these and other social wasps (Polistinae and Vespinae) is a jelly-like substance that the Stenogastrinae secrete from the Dufour 's gland and use in many functions of their biology. It is suggested that this substance greatly contributed to the evolution of social life in these wasps by making it possible to nourish the brood with liquid food and store it in the nest, thus favoring also the evolution of the behavioral mechanisms which facilitated interactions between adults. Social organization of the colonies may have been kept at a low level through a basic system of continuous temporary helper replacement, while the evolution of large colonies was restrained, as well as by the poor quality of construction material, low egg-laying capacity and limited production of abdominal substance, imperfect social regulatory mechanisms, and the absence of defensive mechanisms of the colonies against large predators.     

Morphological changes in the male accessory glands and testes in Vespula vulgaris (Hymenoptera,Vespidae) during sexual maturation

Abstract. The present study documents the pace of accessory gland and testes degeneration in the wasp Vespula vulgaris by means of a histological and metric approach, that has not been carried out for social wasps so far. To a certain extent, comparison is made with the degenerative processes of the mucus glands of the honeybee drone. In V. vulgaris, no generative tissue is left by the end of 9 d of age, and so degeneration is a fast process. The three different parts of the accessory glands (muscle layer, gland epithelium, and lumen) change with respect to age. The secretory cells of the epithelium reach their maximum activity during the first days of adult life, which results in a maximally filled gland lumen by 9 d. We also provide, for the first time, a histological study of testes degeneration for this species. At eclosion, well‐defined cystic structures are still visible, whereas at 9 d, it is no longer possible to distinguish different cystic structures. The diameter of the testes decreases with respect to age.     

Some aspects of interrelations between ants (Hymenoptera,Formicidae) and polistine wasps (Hymenoptera,Vespidae)

Embodied, situated and enactive aspects of relationships of polistine wasps with ants are considered within the framework of the theory of autopoiesis. The idea of the embodied interaction implies specific nestbuilding and protective behavior in polistine wasps. The paper examines the adaptive role of applying ant repellent on the petiole and nest and the latitude gradient of such behavior in re-social wasp species. The situated interaction is considered in the environmental context: the mortality of Polistes gallicus (L.) colonies as a result of predatory attacks of ants Myrmica bergi Ruzsky is analyzed in the Lower Dnieper basin (Ukraine). The enactive interaction includes both spontaneous autonomous activity of its participants as a result of self-organization and specific features of the spatial structure of the prey’s population forming under the impact of the predator. The applicability of some “predator-prey” models is discussed.