page_title: Hornet
section_title: Life cycle
hierarchical_section_title: Hornet / Life cycle
caption_attribution_description: Hornet life cycle
context_page_description: Hornets are the largest of the eusocial wasps, and are similar in appearance to their close relatives yellowjackets. Some species can reach up to 5.5 cm in length. They are distinguished from other vespine wasps by the relatively large top margin of the head and by the rounded segment of the abdomen just behind the waist. Worldwide, 22 species of Vespa are recognized. Most species only occur in the tropics of Asia, though the European hornet, is widely distributed throughout Europe, Russia, North America, and Northeast Asia. Wasps native to North America in the genus Dolichovespula are commonly referred to as hornets, but are actually yellowjackets.
  Like other social wasps, hornets build communal nests by chewing wood to make a papery pulp. Each nest has one queen, which lays eggs and is attended by workers that, while genetically female, cannot lay fertile eggs. Most species make exposed nests in trees and shrubs, but some build their nests underground or in other cavities. In the tropics, these nests may last year-round, but in temperate areas, the nest dies over the winter, with lone queens hibernating in leaf litter or other insulative material until the spring.
context_section_description: In V. crabro, the nest is founded in spring by a fertilized female known as the queen. She generally selects sheltered places such as dark, hollow tree trunks. She first builds a series of cells (up to 50) out of chewed tree bark. The cells are arranged in horizontal layers named combs, each cell being vertical and closed at the top. An egg is then laid in each cell. After 5–8 days, the egg hatches. Over the following two weeks, the larva progresses through five stages of development. During this time, the queen feeds it a protein-rich diet of insects. Then, the larva spins a silk cap over the cell's opening, and during the next two weeks, transforms into an adult, a process called metamorphosis. The adult then eats its way through the silk cap. This first generation of workers, invariably females, now gradually undertakes all the tasks formerly carried out by the queen (foraging, nest building, taking care of the brood, etc.) with the exception of egg-laying, which remains exclusive to the queen.
  As the colony size grows, new combs are added, and an envelope is built around the cell layers until the nest is entirely covered, with the exception of an entry hole. To be able to build cells in total darkness, they apparently use gravity to aid them. At the peak of its population, which occurs in late summer, the colony can reach a size of 700 workers.
  At this time, the queen starts producing the first reproductive individuals. Fertilized eggs develop into females (called "gynes" by entomologists), and unfertilized ones develop into males (sometimes called "drones"). Adult males do not participate in nest maintenance, foraging, or caretaking of the larvae. In early to mid-autumn, they leave the nest and mate during "nuptial flights".
  Other temperate species (e.g., the yellow hornet, V. simillima, or the Oriental hornet, V. orientalis) have similar cycles. In the case of tropical species (e.g., V. tropica), life histories may well differ, and in species with both tropical and temperate distributions (such as the Asian giant hornet, V. mandarinia), the cycle likely depends on latitude.
caption: Life history of Vespa crabro
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