The median wasp (Dolichovespula media) is a species of social wasp of the family Vespidae found throughout Europe and Asia. It builds aerial paper nests often in shrubs or trees, and occasionally under the eaves of buildings. It is most common to see this wasp between May and October during its 3.3 month colony cycle. Behaviours of this wasp include nest defense, curling which is believed to function in brood incubation, and gastral vibration which is involved in larval feeding. The median wasp has a halplodiploid sex determination system that results in a high level of relatedness within the colony. This species is not usually aggressive but will sting if they feel their nest is threatened. Most foraging in the nest is done by the workers once the first ones reach adulthood. These workers forage for insects, nectar, and wood for nest construction in temperatures as low as 7 °C (45 °F). The median wasp is known to be occasionally affected by the fungus Cordyceps sphecocephala and the Cricket paralysis virus.
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DiurnalDiurnal animals are active during the daytime, with a period of sleeping or other inactivity at night. The timing of activity by an animal depends ...
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TerrestrialTerrestrial animals are animals that live predominantly or entirely on land (e.g., cats, ants, snails), as compared with aquatic animals, which liv...
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OviparousOviparous animals are female animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive...
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starts withD. media is a medium to large species of wasp around 16–22 millimetres (0.63–0.87 in) in length with yellow and black stripes on its abdomen. It can be identified by its yellow clypeus with a thin black central line and large areas of yellow behind the eyes and on the ocular sinus. The median wasp also has a shiny black thorax with four yellow spots that are tinted orange or red. Queens are often mistaken for hornets due to their reddish colouration, but can be distinguished by their thoracic spots and deep black color.
The median wasp has a Palearctic distribution and is found throughout Europe and temperate regions of Asia all the way east to Japan. It prefers temperate climates and high humidity. This species was identified in the United Kingdom for the first time in 1980 after having spread there from continental Europe. It has also been sighted in New Zealand, but it is not known if the wasp is widespread in the area or if this was an isolated occurrence.
D. media builds aerial paper nests 1 to 5 metres (3.3 to 16.4 ft) above ground. These nests are typically found in shrubs, trees, and sometimes under the eaves of buildings. Nests are made of paper that comes from the digestion of wood and are generally 12–23 centimetres (4.7–9.1 in) wide and 10–30 centimetres (3.9–11.8 in) tall. Colonies are often found in both urban and rural areas. These wasps prefer to build nests close to the ground where humidity levels are higher as well as in open areas where the nest is subject to large amounts of sunlight.
In the median wasp foraging activities take place throughout the day and can be done in temperatures as low as 7 °C (45 °F). The queen is responsible for all nest construction and foraging until after the first workers emerge from the nest as adults. This means the queen does all of the foraging for about 30 days before workers take over. At the beginning she mainly focuses on collecting fiber for envelope construction, but as the colony begins to develop she allots more time for foraging for food including both flesh and liquid. Workers begin helping with larval feeding and nest development when just a few days old and take their orientation flight at about 5 days old. At this point they begin to take over food and material collection for the nest. These foraging trips can last between a few minutes to one hour, but most are less than 10 minutes in length. As D. media searches for prey it stops for a moment over each flower in contrast to other species such as V. flaviceps which quickly fly up and down each plant. They will fly up to a couple hundred meters to forage for food.
