Local dynamics of worker activity of the invasive Vespula germanica and V. vulgaris (Hymenoptera: Vespidae) wasps in Argentina

1. The abundance of insects depends essentially on the reproductive success of individuals. In social insects, however, the abundance of sterile workers outside a nest depends on colony size but is also determined by ontogeny, nest demands, and local environmental factors. For invasive social wasps, the drivers of worker abundance are important because they determine the impact that these species have on the native systems, people, and their goods. 2. The aim of the present study was to understand the relative importance of endogenous and exogenous factors on the abundance of workers of populations of Vespula spp., by analysing 12 years of trap captures in NW Patagonia. This is the first attempt to model the activity levels of invasive Vespula spp. wasps over time in Argentina. 3. It was shown that between years, the worker activity of both vespids presents fluctuations, and that of V. germanica is determined by the spring mean temperatures. Within the flight season, V. germanica worker activity is affected by the relative abundance of workers in that year, whereas for V. vulgaris, activity it is affected by the relative abundance of both species that year. We found no relationship between individual weather variables and activity within a flight season for both wasps. 4. The patterns observed for Argentina are similar to those observed in all invaded temperate areas where Vespula spp. are established. This study provides useful information to understand the driving factors that affect Vespula spp. worker activity in Argentina. This could be a necessary step to develop plans to manage these invasive social insects.     

Competition for honeydew between two social wasps in South Island beech forests,New Zealand

Summary Honeydew is a sugary secretion of beech scale insects (Ultracoelostoma spp.). Two introduced species of wasps forage on the sugar droplets in New Zealand beech forests. We hypothesize that competition between them may explain whyVespula germanica has become locally extinct in beech (Nothofagus) forest invaded byV. vulgaris. Changes in behaviour of the two wasp species in response to changes in the honeydew resource were monitored. Foraging and rainfall separately and together reduced the honeydew standing crop. In response to the standing crop decreasing, more wasps were found on honeydew trees, they became less active, spent more time lapping the tree surface, and ingested drops of honeydew at a slower rate.V. vulgaris was more active, and obtained drops and energy at a higher rate thanV. germanica. These behavioural differences may lead to competitive advantages affecting queen size and possibly survival.     

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.     

Foraging and spatial dispersion in protein-scavenging workers ofVespula germanica andV. maculifrons (Hymenoptera: Vespidae)

A series of experiments on the discovery of meat bait by scavenging workers ofV. germanica andV. maculifrons showed that workers oriented to meats by visual cues and olfactory cues. Scavening workers ofV. germanica andV. maculifrons responded positively to the sight of conspecifics at meat baits; i.e., meat with (confined) wasps received more visits than meat without wasps. This attraction to conspecific workers on meat baits provides evidence of local enhancement, in that the presence of conspecifics at meat bait directs other wasps to a particular spatial locality. Local enhancement by yellowjackets foraging for meat may contribute to the clumped distribution of worker populations noted in studies of workers captured in meat-baited traps. We hypothesize that local enhancement of foraging is a ubiquitous behavior in species of theV. vulgaris species group and may be one attribute explaining their ecological success.     

Variation in colour markings of German wasps Vespula germanica (F.) and common wasps Vespula vulgaris (L.) (Hymenoptera: Vespidae) in New Zealand

Abstract

German wasps (Vespula germanica F.) and common wasps (V. vulgaris L.) both show variations in colour markings in New Zealand. Overlap in the ranges of markings of the head and thorax is limited enough for ready distinction of queens and workers of the two species. Abdominal markings overlap considerably between the species. Colour markings of males were too similar to identify the species, which were completely separated by the shape of their genitalia. The frequency of occurrence of “intermediate” markings in V. germanica populations did not increase in areas where the two species overlap. This suggests there is little or no genetic exchange between the two species.     

Polymorphic microsatellite loci for eusocial wasps (Hymenoptera: Vespidae)

Hymenopterans are an important model for studying the evolution of cooperation in animal societies. Here, we characterize 19 microsatellite loci, isolated from the common wasp Vespula vulgaris, that can be used to study genetic variation in three genera (seven species) within the Vespidae. The number of alleles in V. vulgaris was moderate, varying from 2 to 14, with expected heterozygosity ranging between 0.04 and 0.93. Eleven loci amplified DNA in V. austriaca and Dolichovespula sylvestris, nine in V. germanica, eight in Vespa crabro and V. rufa, seven in D. media and only five loci could be used for D. norwegica.     

The impact of an exotic social wasp (Vespula germanica) on the native arthropod community of north-west Patagonia, Argentina: an experimental study

Abstract 1. Biological invasions are usually thought to have a negative impact on native communities. However, data supporting this idea are often based on comparative studies between invaded and non‐invaded areas, and are spatially and temporally limited. 2. The present study experimentally assessed the impact of an exotic wasp, Vespula germanica, on the native arthropod community of north‐west Patagonia during 3 years in an area of 80 ha. Vespula germanica is an exotic social vespid that invaded north‐west Patagonia 20 years ago. It has been suggested that its populations affect native arthropods because of its broad diet and also because Patagonia lacks natural enemies and potential competitors for these wasps. 3. Using wasp‐specific toxic baits, V. germanica abundance was reduced in five sites of native woodlands during 3 consecutive years. The abundance, species richness, and composition of arthropods between non‐poisoned (control) and poisoned sites was then compared, both before and after the wasps were poisoned. 4. Wasp abundance represented 6% of the total arthropod catches in non‐poisoned sites and was reduced, on average, by 50% in the treated areas. The abundance, species richness, and composition of the arthropod community (305 species, 24 600 individuals) did not differ between control areas and areas where the abundance of V. germanica was reduced. Significant differences in response variables were found only before wasp poisoning had begun and were related to variations among sites. 5. These results suggest that V. germanica is not affecting the local arthropod assemblages, contradicting past work in other regions. The low relative abundance of wasps in Patagonia, when compared with other invaded regions, might explain the findings. 6. The present study provides further evidence for the importance of large‐scale experimental work with before/after comparisons to fully understand the impact of invaders on natural communities.     

Length of burning rotation and community composition in high-level Calluna-Eriophorum bog in N England

Studies on a long-term experiment on Calluna-Eriophorum bog indicate that the length of time between management fires affects the post-fire development. A short rotation (every 10 years) results in increased dominance by Eriophorum spp. while a long rotation (every 20 years) results in greater abundance of Calluna vulgaris after fire. Variations in post-fires species abundances are related to pre-fire stand composition coupled with the patchy distribution of regeneration centers of rhizomatous species. The usefulness of burning this vegetation type in management for herbivore grazing is questioned.Nomenclature follows Tutin et al. (1964 80) for vascular plants. Smith (1978) for mosses, Watson (1981) for liverworts and Hawksworth, James & Coppins (1980) for lichens. Following common practice. Calluna vulgaris is referred to simply as Calluna. Acknowledgements. I thank M. Raves and the Nature Conservancy Council for permission to work on Moor House National Nature Reserve and for the use of data from Reserve Records, V. J. Hobbs for field assistance, and Prof. C. H. Gimingham for help and advice during the study. I also thank all who worked at Moor House for creating a pleasant working environment. The long-term experiment was planned by Dr R. J. Elliot and analyzed initially by Dr G. I. Forrest.     

Zum Sammelverhalten von Wespen

Zusammenfassung An einer im Zimmer aufgestellten Futterquelle wurden in Abhängigkeit von der Zuflussgeschwindigkeit der Zuckerlösung verschiedene Verhaltensweisen Zuckerwasser sammelnder Wespen (Paravespula germanica undP. vulgaris) gemessen.Mit zunehmender Zuflussgeschwindigkeit wächst die, Abflugmagenfüllung, die Anzahl der Saugunterbrechungen pro Besuch nimmt ab.Die Länge der Besuchspausen bleibt über weite Bereiche der Zuflussgeschwindigkeitsskala annähernd konstant.Die Ergebnisse werden mit an der, Honigbiene (Apis mellifica) gewonnenen verglichen.

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Summary The activities of wasps (Paravespula germanica andP. vulgaris) that were collecting sucrose syrup were measured when the rate at which the syrup was supplied was varied.The volume of syrup each wasp collected per trip became greater as the rate of supply was increased. Drinking was interrupted at low rates of supply; the number of the interruptions per visit decreased when the rate increased.The length of the visit pause remained nearly constant even when the rate of supply varied considerably.The results obtained with the wasps are compared with those obtained with the honeybee (Apis mellifica).

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Résumé Différentes activités de guêpes (Paravespula germanica etP. vulgaris) qui collectionnaient une solution de sucre de canne étaient mesurées en relation de la vitesse de l'afflux de la solution.Quand la vitesse de l'afflux augmente, la quantité collectée durant une visite à la source de nourriture devient plus grande. Quand la vitesse de l'afflux est très réduite, les guêpes ne boivent pas continuellement, elles font des interruptions. Le nombre des interruptions durant une visite diminue, quand la vitesse de l'afflux augmente.La durée des pauses entre les visites reste à peu prés la même quand la vitesse de l'afflux est variée considérablement.Les résultats sont comparés avec ceux gagnés avec l'abeille (Apis mellifica).

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«Wespe» bedeutet im folgenden die GattungParavespula (germanica undvulgaris); mit «Biene» ist die HonigbieneApis mellifica gemeint.     

Foraging niche separation of social wasps in an invaded area: Implications for their management

Foraging niche separation may be a mechanism to promote coexistence of two competing species by concentrating intraspecific competition relative to interspecific competition. The present study investigated foraging behaviour and microhabitat use of two coexisting species of invasive social wasps, Vespula germanica and Vespula vulgaris, when foraging for two different food resources. Also, we tested the attractiveness of traps baited with a synthetic lure for those two species. We found that V. germanica wasps prefer to forage at ground level regardless of the resource, while V. vulgaris prefers protein resources at the shrubland level given a choice between a protein bait at ground or at shrubland level. However, when baited with the synthetic lure, the species caught was not affected by the height at which traps were placed. That is, in a no choice scenario, the traps were sufficiently attractive to lure both species of wasps to both microhabitats (ground and shrubland levels). Thus, our results support the existence of spatial niche differentiation at least in protein foraging and suggest that the synthetic lure evaluated could be used to trap both species of Vespula wasps present in Argentina. These results could help to improve management strategies of these social wasps in an invaded area.     

A biometric study of seasonal variation in worker wasps (Hymenoptera: Vespidae)

The seasonal changes in some morphometric characters of worker wasps of Vespula vulgaris and Vespula germanica are described and discussed in relation to colony populations and economics.     

饵料蛋白水平对德国小蠊肠道细菌群落的影响

昆虫肠道微生物在宿主营养代谢、生长发育、免疫以及抵御病原菌等方面具有重要作用。研究不同蛋白水平饵料饲养对德国小蠊（Blattella germanica）雄成虫肠道细菌群落组成及其功能的作用,探究德国小蠊肠道细菌对宿主营养和健康的影响,以期为发展生物防治的诱食性饵料提供理论支持。分别取连续饲喂低蛋白（LP2组：5%）、高蛋白（HP3组：65%）以及正常蛋白水平饵料（CD1组：25%）21 d的德国小蠊雄成虫,饥饿24 h后无菌条件下分离并提取肠道总基因组DNA,采用特异引物扩增细菌16S rDNA的V4可变区并进行高通量测序,分析德国小蠊肠道细菌群落组成及其功能特征。结果表明德国小蠊肠道细菌主要由拟杆菌门（Bacteroidetes）、变形菌门（Proteobacteria）、梭杆菌门（Fusobacteria）和厚壁菌门（Firmicutes）等细菌群落组成。饲喂低蛋白饵料LP2组的德国小蠊肠道细菌中拟杆菌属（Bacteroides）细菌丰度（47.44%）显著高于HP3组（23.97%）和对照CD1（7.04%）。饲喂高蛋白饵料的HP3组梭杆菌门丰度显著高于其他两组。LEfSe物种差异分析也表明HP3组德国小蠊肠道细菌中梭杆菌属（Fusobacterium）细菌与低蛋白饵料LP2组和对照CD1组有显著差异。基于Tax4Fun功能预测显示,HP3高蛋白饵料组的德国小蠊肠道细菌中与能量代谢功能相关基因的相对丰度极显著高于对照组CD1组,外源性物质代谢与降解和其他氨基酸代谢功能基因的相对丰度显著高于低蛋白LP2组。本研究结果表明饵料中蛋白质水平的差异能够显著改变德国小蠊肠道中细菌群落结构组成,并影响其代谢功能。     

The abundance and distribution of caddisflies (Insecta: Trichoptera) caught by emergence traps in the 'Ritrodat' research area of the Lunzer Seebach (Lower Austria) from 1980 to 1982

SUMMARY. 1. Adult Trichoptera were caught during 3 years (1980–82) in the ‘Ritrodat’ research area of the Upper Lunzer Seebach. a mountain brook near Lunz. Lower Austria, using a set of thirty pyramid type emergence traps. During the three collecting periods (112 collecting days) a total of 1810 specimens were caught. The most abundant species were Micrasema minimum McL. (Brachycentridae). Rhyacophila vulgaris Pictet (Rhyacophilidae), and the three Iimnephilid species Potamophylax cingulatus Steph., Allogamus auricollis Pictet and Ecclisopteryx guttulata Pictet. 2. In six species (Micrasema minimum, Rhyacophila vulgaris, Atlogamus auricollis, Ecclisopteryx guttulata, Drusus biguttatus Pictet, Chaetopteryx fusca Brauer) the sex ratio was significantly different from 1:1. In Micrasema minimum 422 females were caught but only three males. 3. In each year there were peaks in total emergence in early summer and early autumn. 4. The length of the emergence period of the most abundant species ranged from 38 days in Micrasema minimum to 210 days in Rhyacophila vulgaris (mean values 1980–82); there was also a difference in the intensity of emergence in these species: the percentage of time required for 50% of the animals to emerge (0%=onset of emergence, 100%= emergence completed) was 16% in Allogamus auricollis but 71% in Rhyacophila vulgaris (mean percentages 1980–82). 5. The distribution pattern of individuals per trap was tested against a Poisson distribution; in all three years the distribution was contagious. 6. The dry weight of specimens of Drusus biguttatus, Micrasema minimum. Ecclisopteryx guttulata and Wormaldia copiosa McL. was measured and. together with published dry weight values of other species (Malicky, 1976), these data were used to estimate the biomass emerging annually of twenty-three species of Trichoptera (99.2% of emergence, 1980–82). This was equivalent to 35.3 kJ m^?2 in 1981 and 32.5 kJ m^?2 in 1982.     

The spread of the social wasp,Vespula germanica,in Australia

Abstract

Between 1977 and 1989 the social wasp Vespula germanicacolonised mainland Australia and became established in New South Wales, Victoria, and South Australia. Accidental transport between towns is the main mechanism of spread. In many towns wasp nests have not been detected until they became widespread; therefore, eradication is difficult Successful eradication has, however, been achieved in many other towns.

Nesting places vary considerably among localities but relatively little among years at anyone locality. Peak wasp abundance occurs between January and April. Control of V. germanica nests costs Australia an estimated $600,000 (Aust. $) annually.     

Distribution of social wasps (Hymenoptera: Vespidae) in New Zealand in 1987

Abstract

More than 50 000 social wasps (Hymenoptera: Vespidae) were collected between March and August 1987 from throughout New Zealand. The most widespread species is the German wasp (Vespula germanica). The common wasp (V. vulgaris) has colonised about half the country and appears to be still spreading. It tends to appear in urban areas first, presumably because it is transported there with people and/or their belongings. The Asian paper wasp (Polistes chinensis) and Australian paper wasp (P. humilis), are confined to the northern half of the North Island, but the former species is spreading south.     

Long‐term abundance trends of the northern form of the short‐finned pilot whale (Globicephala macrorhynchus) along the Pacific coast of Japan

The abundance of the northern form of the short‐finned pilot whale, Globicephala macrorhynchus, in the Pacific waters of northern Japan was estimated from a line transect survey conducted in 2006 and data from seven previous surveys collected between 1985 and 1997. To overcome the difficulty of small sample size and inconsistency in survey design, we used an adjustment method using multiple covariates and sensitivity analysis by considering several scenarios. Abundance estimates showed similar long‐term trends among scenarios. The northern form of G. macrorhynchus was more abundant in 1985 than in 1991–2006. The annual catch of the northern form of G. macrorhynchus exceeded the potential biological removal (PBR), especially in the 1980s. Thus, the commercial take in the early 1980s was suspected as a partial cause of a serious abundance decrease. These results provide valuable information for interpreting the impacts of coastal whaling, and to develop future management plans.     

The structure of temperate yellowjacket communities is affected by land development and loss of forest cover

1. As anthropogenic disturbance continues to encroach on natural areas, it is imperative to establish how this disturbance affects species assemblages. Yellowjackets are important predators of a wide range of arthropods, acting as natural population control in many ecosystems. This study seeks to explore how Vespinae community structure shifts with increasing land development in a temperate North American environment.
2. Yellowjackets were sampled from May to September 2019 using heptyl butyrate and acetic acid plus isobutanol traps. Sampling sites represented a gradient of developed landscapes, from fully forested to entirely developed. Seven species from the genera Dolichovespula and Vespula were trapped during the study.
3. Yellowjacket community structure was found to be significantly affected by the amount of land development. These results were driven by the replacement of Vespula consobrina with Vespula germanica in urban landscapes. A high level of development, greater than 75%, reduced species abundance relative to the fully forested landscapes, primarily due to the loss of Vespula pensylvanica and V. consobrina.
4. Our results highlight that the replacement of forested areas with urban development causes a shift in yellowjacket community composition, favouring generalist scavengers (e.g. V. germanica) and threatening the abundance of forest specialists such as V. consobrina.

     

The potential distribution of German wasps (Vespula germanica) in Argentina

Abstract

In the early 1980s, the German wasp (Vespula germanica) arrived in Argentina and became established in northern Patagonia. We use an ecoclimatic computer‐based program (CLIMEX) to predict the potential spread of wasps to other areas of the country. The model suggests that much of Argentina does not appear to be very suitable for the species’ establishment. However, more suitable areas than those currently colonised by the wasp occur in the centre of the country. Based on CLIMEX results, we suggest that, if the wasps ever break through the barrier of unfavourable habitat that surrounds their current distribution, they will continue dispersing to those areas. Notwithstanding this, factors other than climate may explain why German wasps are firmly established in areas otherwise considered to be inhospitable for the species.     

Characteristics of woods used recently and historically by Lesser Spotted Woodpeckers Dendrocopos minor in England

Lesser Spotted Woodpecker Dendrocopos minor numbers have declined greatly in England since the early 1980s for reasons that are not yet fully understood. It has been suggested that the species’ decline may be linked to the increase in Great Spotted Woodpeckers Dendrocopos major, changes in woodland habitat quality (such as deadwood abundance) and landscape‐scale changes in tree abundance. We tested some of these hypotheses by comparing the characteristics of woods in southern England where the species is still relatively numerous with those of woods used in the 1980s before the major decline. In each time period, habitat, predator and landscape information from woods known to be occupied by Lesser Spotted Woodpeckers was compared with those found to be unoccupied during surveys. Before the main period of decline, Lesser Spotted Woodpeckers used oak‐dominated, mature, open woods with a large amount of standing deadwood. Habitat use assessed from recent data was very similar, the species being present in mature, open, oak‐dominated woodlands. There was a strong relationship between wood use probability and the extent of woodland within a 3‐km radius, suggesting selection for more heavily wooded landscapes. In recent surveys, there was no difference in deadwood abundance or potential predator densities between occupied and unoccupied woods. Habitat management should focus on creating and maintaining networks of connected woodlands in areas of mature, open woods. Finer‐scale habitat selection by Lesser Spotted Woodpecker within woodlands should be assessed to aid development of beneficial management actions.     

Variation in the phenology and abundance of flowering by native and exotic plants in subalpine meadows

The timing and abundance of flower production is important to the reproductive success of angiosperms as well as pollinators and floral and seed herbivores. Exotic plants often compete with native plants for space and limiting resources, potentially altering community floral dynamics. We used observations and a biomass-removal experiment to explore the effects of an invasive exotic flowering plant, Linaria vulgaris, on community and individual species flowering phenology and abundance in subalpine meadows in Colorado, USA. Invasion by L. vulgaris was associated with a shift in both the timing and abundance of community flowering. Invaded plant communities exhibited depressed flowering by 67% early in the season relative to uninvaded communities, but invaded sites produced 7.6 times more flowers than uninvaded sites once L. vulgaris began flowering. This increase in flowers at the end of the season was driven primarily by prolific flowering of L. vulgaris. We also found lower richness and evenness of resident flowering species in invaded plots during the period of L. vulgaris flowering. At the species level, a common native species (Potentilla pulcherrima) produced 71% fewer flowers in invaded relative to uninvaded plots, and the species had reduced duration of flowering in invaded relative to uninvaded sites. This result suggests that L. vulgaris does not simply alter the flowering of subordinate species but also the flowering of an individual common species in the plant community. We then used observational data to explore the relationship between L. vulgaris density and resident floral production but found only partial evidence that higher densities of L. vulgaris were associated with stronger effects on resident floral production. Taken together, results suggest that a dominant invasive plant can affect community and individual-species flowering.