Social wasp fast facts |
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The social wasps are in the Vespidae family. there are 4000 species world wide, and eight species in Britain. Their life cycle is similar to Bumblebees, in that it is annual, with only the newly mated queens surviving the winter by hibernating (see for recent changes in Hawaii and New Zealand). Wasp queens do not hibernate underground as bumblebees do, but usually choose a dry, cool, sheltered spot. I regularly find queens hanging on by their jaws to the underside of logs in my wood pile. Adults range in size from 10 - 30 mm long.
Social wasps in Britain |
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Dolichovespula media |
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Dolichovespula norwegica, Norwegian wasp |
| Dolichovespula sylvestris Tree wasp Queens up to 18 mm, workers up to 16 mm. Flies May to September Found throughout U. K., also in Europe, Morocco, across central Asia into China, often nests in gardens, in tree holes, bird boxes and roof spaces. Colony size is small. Queens fly from early May, workers from June, and new queens and males from July. Intriguing research has found that this wasp is getting smaller. Research in Spain using museum specimens that date back to 1904 has found a decrease in wing size. This decline in size correlates with a rise in temperature. Temperature increase has been shown to lead to a decrease in size of vertebrates, e. g. antelope and sparrows. The team that produced the results are unsure if climate change is the cause, but it is known that an higher temperature does speed up grub development in wasps. This speedy development leads to earlier emergence as adults and a smaller average adult size. These results have implications for many other holometabolous insects. Many museums hold collections that could be used in such studies. |
| Dolichovespula saxonica, Saxon wasp First seen in the U. K. in 1987, and the first nest in East Sussex in 1991. Closely related to the Norwegian wasp, but more commonly found in urban locations. Colony size is small. |
| Vespa crabro, the hornet Q 23 - 25, W 18 - 15, M 21 - 28 Flies May - Aug Head, thorax and abdomen with orange/brown instead of yellow/brown |
| Vespula germanica, German wasp Q 17 - 20, W 12 - 16, M 13 - 17 Flies March - Sep 3 small black spots between eyes. Nest in cavities and holes in the ground. Nest size can reach a diameter of 1.8 m and contain thousands of individuals. |
| Vespula vulgaris, the common wasp Q 16 - 19, W 11 - 15, M 13 - 17 Flies Apr - Sep Anchor-shaped mark between eyes. Nests in cavities, holes in ground, attics, out houses, bushes, almost anywhere. Nest can be as large as 2.25 m in diameter, and can be active as late as November in the south of England. |
| Vespula rufa, red wasp Q 16 - 20, W 10 - 14, M 13 - 16 Flies Apr - Sep. Found throughout Britain. Colonies can now survive until November in favourable conditions. 2 abdominal segments nearest abdomen have orange/red patches. Prefers drier soil types. Nests at ground level or underground, in grassy tussocks, tree stumps and out houses. |
| Vespula austriaca Females 19 mm This is a cuckoo wasp on Vespula rufa. The female invades V. rufa's nest when there are just a few workers. She kills the queen and lays her own eggs leaving V. rufa's workers to rear them. Found only where V. rufa is found. |
Wasp grubs (see the drawing below) are carnivorous, the adults bring them prey which is mainly other insects. This is chewed up into a paste by the workers and queen and fed to the grubs. An adult wasp can fly with prey that weighs 4/5 of her own body weight back to the nest. As many of these prey items are regarded as "pests" by gardeners, it is clear that the wasp should be regarded as the gardener's friend.
Adult wasps prefer sweet foods such as nectar, jam, ice cream, and as the adults feed the grubs the grubs exude a sweet liquid which the adult wasps lap up. Towards the end of summer when the queen has stopped laying eggs and all the grubs have hatched into adults, there is no more need for the adult wasps to bring back insect prey, and no grubs to give the adults the sweet substances they crave. So the adults go out and search for sweet substances. They find sweet nectar in flowers, but as they have short tongues they cannot reach the nectaries of some flowers. It is at this time of year that wasps become a nuisance to man if they discover our sweet foods such as sugar, jam, ice cream, etc. In northern Europe wasps do not store food in their nests.
The larvae (above) are carnivorous eating chewed up bits of insects fed to them by adult wasps. In return the grubs exude a sweet secretion in their saliva which is lapped up by the adult wasps. The grub moults three times, and tightly fits its cell after the last moult.
The Vespula vulgaris queen above and below is 16 - 19 mm long. The nest is started by the queen, and is about the size of a walnut and contains 10 - 12 hexagonal cells. The queen then lays an egg in each cell. The cells point downwards, but the egg is partially stuck to the side, so it does not fall out. On average each cell is used twice.
Above you can see a close up of a queen's head showing the 3 simple eyes or ocelli.
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