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Taxonomic name: Vespula germanica Synonyms: Common names: Avispa comun (Spain), Avispa germánica (Spain), Deutsche Wespe (Germany), European wasp, German wasp, German yellowjacket, Guêpe germanique (French), Vespa germanica (Italy) Organism type: insect Vespula germanica, commonly known as the German or European wasp, is a social wasp species. In introduced regions, where it is often more successful than in its native range, it efficiently exploits important food resources, such as nectar and insects, that native fauna may depend on. Vespula germanica display many characteristics that make a species a successful invader and a new colony can be established from a single inseminated female. Description Adult Vespula germanica are 12mm to 17mm long (queens may be up to 20mm long) with a blackish brown pedunculate abdomen and bright yellow stripes. They have strong black markings including an arrow-shaped mark down the middle of the abdomen a black spots on either side. Wings are long and translucent, legs are yellow and antennae black. Antennae are divided into 12 or 13 segments depending on gender (males have 13) and the abdomen is divided into 6 or 7 segments also depending on gender (males have 7). Females are equipped with an ovipositor (HYPPZ 1998; CISRO 2005). Please see PaDIL (Pests and Diseases Image Library) Wasps: European wasp Vespula germanica (Fabricius) for high quality diagnostic and overview images. Occurs in: agricultural areas, natural forests, planted forests, scrub/shrublands, urban areas Habitat description Vespula germanica usually nests underground in holes dug in the soil. Alternatively it may construct its nest in the crevices of tree trunks or stacked materials or in compost or hedges. In urban areas the possibilities are even greater and wasps often nest in walls, roof spaces or other convenient gaps in buildings (Ward et al. 2002). In urban areas, 30% of nests are located in buildings while in rural or forested areas up to 100% of nests are found in the ground (Moller et al. 1991). (The nest is nearly always concealed from view and has a 2 to 3cm wide opening. The cells and walls of the nest are made from bits of young wood and tree bark, which are chewed by the worker and mixed with saliva to form a special paste used to fabricate the nest, which may be the size of a football (HYPPZ 1998; AM 2005; CSIRO 2005). V. germanica may invade both disturbed environments and natural ecosystems. In Patagonia (Argentina) V. germanica is present in native beech forests in low densities (Sackmann et al 2001). It has been noted that human activities that fundamentally change environments may encourage wasp colonisation; in the Rio Negro valley (also in Argentina) fruit production and irrigation have made food and water resources unexpectedly plentiful for wasps and has thus favoured their establishment (D'Adamo et al. 2002). It is suggested that climate is an important determinant of invasion success (Kemper 1960, Edwards 1976, Madden 1981). A slightly longer wasp-activity season exists in the warmer parts of Australia (Sydney) than in the cooler parts (Melbourne, Hobart) (Ward et al. 2002). V. germanica is sensitive to prolonged extreme temperatures and is restricted to the temperate regions of Asia (Spradbery and Maywald 1992). Vespula spp. may be suppressed by high rainfall and low temperature as underground nests are susceptible to flooding (Fox-Wilson 1946; Akre and Reed 1981; Barlow et al. 2002). General impacts Vespula germanica has a range of serious economic, health and ecosystem impacts. In terms of humans, they can be a major social pest as they disrupt people’s enjoyment of the outdoors (Beggs 2000). Furthermore they have a painful sting and are a threat to human health (McGain et al. 2000, Mingomataj 2003). Wasp stings are painful at best, and life-threatening at worst. A small proportion of the population will have a severe allergic reaction (called anaphylactic shock), which can be fatal unless treated promptly (Landcare Research 2007). V. germanica are polyphagous (feeding on many different kinds of food), opportunistic predators, with a preference for insects. They are scavengers and will collect sugary solutions, such as honeydew, if available. In forests wasps may eat huge numbers of native insects and consume large quantities of sugary honeydew. By eating so much, wasps take potential food sources away from native animals and disrupt the natural food chain and ecosystem cycling of the forest (Landcare Research 2007). To elaborate, in temperate beech forests in the South Island of New Zealand honeydew drops produced by beech scale insects (Ultracoelostoma assimile) feeding on beech trees (Nothofagus) are collected by introduced wasp species: the German wasp (V. germanica), and the common wasp (Vespula vulgaris). Moller and colleagues found that in relation to cropping by native honeyeater birds and native insects, cropping by German wasps, and particularly by common wasps, significantly reduces the number, size, and sugar concentration of honeydew drops (by up to 99.1%) (in the summer and autumn months). Removal of the honeydew by the introduced social wasps threatens the existence of some New Zealand native animals (Moller et al. 1991). Other components of the ecosystem which may be affected include the proportion of invertebrate prey items available. In Australia German wasps may have a detrimental effects on native invertebrates via predation and competition (Kasper 2004). Similar effects are seen in scrubland-pasture habitat in New Zealand, were large over wintering colonies account for much of the biomass of prey consumed (Harris 1996). High densities of wasp cause local predation pressure on prey and a depletion of carbohydrate sources. The continuous activity of these colonies eliminates the opportunity for these prey species to recover. Wasps bring a financial burden with them too. They are economic pests of primary industries such as beekeeping, forestry and horticulture (Beggs 2000). Wasps totally destroy or seriously affect 10% of beehives, which translates to a significant financial loss (Clapperton et al. 1989). Beehives are often placed near honeydew forests or other unique sources of nectar to produce strong-flavoured honey. However, wasps can reduce honey production by reducing nectar and honeydew supplies and cause honeybees to stay home to conserve energy and protect their hive from raiding wasps (Landcare Research 2007). Geographical range Native range: Vespula germanica is native to the Palearctic region: Europe, North Africa and temperate regions of Asia (Spradbery and Maywald 1992). Known introduced range: V. germanica has been introduced into New Zealand, Tasmania, Australia, Ascension Island, South Africa, the United States, Canada, Chile, and Argentina (Spradbery and Maywald 1992, Clapperton et al. 1994, Archer 1998, Farji-Brener and Corley 1998, Matthews et al. 2000, D'Adamo et al. 2002). Introduction pathways to new locations Agriculture: Aircraft: Seafreight (container/bulk): Inseminated queens search for well-insulated places in which to hibernate, a feature that can have important consequences on wasp dispersal. Queen hibernation behaviour has meant their survival in cargo to distant parts of the world (Spradbery and Maywald 1992). Transportation of habitat material: Local dispersal methods Natural dispersal (local): On animals (local): Transportation of habitat material (local): Management information Preventative measures: The early detection of establishing populations is important as the next line of defence after initial quarantine procedures. Landcare research has conducted research into generalised invertebrate surveillance techniques in recognition of the gap in biosecurity surveillance. These include malaise traps, mini-malaise traps, window traps, sticky traps, pitfall traps, UV light traps, flat ant traps, baited ant pottles, spurr wasp traps, ground bottle traps, yellow pan traps and beating. Of these, malaise traps, mini-malaise traps, window traps, sticky traps (for small wasps), UV traps, spurr wasp traps and ground bottle traps were found to be effective at catching wasps. Please follow this link for descriptions of trapping methods: http://www.landcareresearch.co.nz/research/biocons/invertebrates/id_surveillance.asp . Chemical There are two ways of reducing a local wasp problem - either finding and destroying all nests in the area, or using poison bait (Landcare Research 2007). Nests can be destroyed by placing a small amount of insecticide powder (such as a permethrin based product) at the nest entrance in dry conditions. Care needs to be taken not to get stung. The advantage of poison bait is that foraging wasps carry the poison back to the nest, meaning it is unnecessary to locate nests or approach those that are very large or difficult to get at (Chang 1988). Vespula wasps are attracted to dead bait such as chicken or fish meat (Toft and Harris 2004). There has been considerable research on developing effective poison-baits (Chang 1988, Spurr 1991, Harris and Etheridge 2001, Sackmann et al. 2001, Warren and Statham 2002, D’Adamo et al. 2003, D’Adamo and Lozada 2005, Wood et al. 2006). In New Zealand a poison-bait is commercially available (Rentokil Wasp Bait), but this is not yet available in other countries. Both methods will only alleviate the problem for the current season and workers foraging for food will reinvade the area. The area will almost certainly be reinvaded next season by queen wasps, which can fly up to 30 kilometres in their search for suitable nesting sites (Landcare Research 2007). Biological: Biological control has been used in attempts to achieve widespread control of wasps. Icheumonid parasitoids Sphecophaga vesparum vesparum, S. v. burra and Sphecophaga orientalis have been utilised as biological control agents for V. germanica (Donovan et al. 1989 2002, Beggs and Harris 2000, Beggs et al. 2002). For more information on biological control of wasps please follow this link: http://www.landcareresearch.co.nz/research/biocons/invertebrates/Wasps/biocontrol.asp . Some other general factors to consider: V. germanica constructs significantly larger nests in New Zealand (part of its introduced range) than it does in Europe; over-wintering of nests (ie: re-using the same nest from one summer to the next) also occurs more frequently in New Zealand than in Europe (Fordham et al. 1991, Harris 1996, in Ward et al. 2002). This suggests the wasp may be harder to control in areas of its introduced range. Fordham et al. (1991) found that urban nests produced more workers and reproductive progeny (and had more combs per nest) compared to rural nests, a factor to consider when planning control strategies (Ward et al. 2002). Temperature variation may also affect the growth and impact of wasp colonies, for example, a slightly longer wasp-activity season exists in the warmer parts of Australia (Sydney) than in the cooler parts (Melbourne, Hobart) (Ward et al. 2002). Nutrition Vespula germanica exploits available fruit and flower resources during the summer, collecting flower nectar and feeding off fermented fruit pulp; workers may also collect secretions from honeydew producing insects. V. germanica hunt and consume arthropods, including flies, mosquitoes and caterpillars; wasp larvae require a protein rich diet of insects and spiders (Harris 1991, Kasper et al. 2004). Reproduction Queens begin constructing nests in spring. The first batch of adult worker wasps emerges to take over the work of enlarging the nest and feeding the larvae, leaving the queen to continue egg-laying (Spradbery 1973). There is continuous enlargement of the nest during summer, to a point in late summer/early autumn when several hundred queens and drones are reared. These usually depart from the nest in autumn and take part in mating flights (Spradbery 1973). In Australia, queens are typically polyandrous (Goodisman et al. 2002). The queens seek winter shelter to hibernate, the males die off, and the remaining occupants usually die, leaving the nest empty. Occasionally, new queens and some workers remain in the nest over the winter period, building the nest up to an extremely large size in the following summer (Spradbery 1973). Reviewed by: Jacqueline Beggs School of Biological Sciences, Tamaki Campus University of Auckland. New Zealand Compiled by: IUCN/SSC Invasive Species Specialist Group (ISSG) with support from the Terrestrial and Freshwater Biodiversity Information System (TFBIS) Programme (Copyright statement) To contribute information, please contact Shyama Pagad. Last Modified: Tuesday, 28 November 2006