|scientific name Vespula consobrina |
common name Blackjacket
Nearctic species restricted to northern region in open Boreal forests, prairies, suburban lawns and pastures.
Colonies are annual and short lived. Queens choose the nest between April and May. The colony decline in mid September.
This species is black with white, ivory or pale yellow markings. The Blackjacket resemble to Baldfaced Hornet and the Northern Yellowjacket, but V. consobrina has no ferruginous markings on abdominal terga 1 and 2. In average the queen size 17 mm, males 15 mm and workers 11 mm. Head: The malar space is below than half as long as the penultimate antennal segment; scape with pale anterior mark; the occipital carina is incomplete; black clypeal mark of female free or extending to clypeus dorsal margin; black clypeal mark of male extending to ventral margin, rarely free; ivory, white or pale yellow strip along inner orbit ending close apex of ocular sinus. Metasoma: the metasomal tergites are covered with long straight hairs; with white or pale yellow bands on metasomal segments; apical fascia on metasomal tergite 1 evanescent or absent; queens have straight fascie on metasomal tergite 4 and 5; male aedeagus with saddle-shaped portion. Xanthic queens with free black discal spots on terga 4 and 5 and linked spots on tergum 2 (Buck et al. 2008, Miller 1961).
The Blackjacket is a social species with annual colonies. Nests mostly are subterranean building in rodent burrows, also in rotten logs, rock cavities or hollow walls, however, the nests are aerial in some cases and they are built in dark and enclosed places. The colonies are small with less than 100 workers in average. The queen burrows about 10-30 cm underground and she adds cells inside the nest, she lays eggs and takes care of the larvae, the first workers emerge from mid to late June. The workers search food and fibers, help with the colony thermoregulation, care the larvae, clean the cells, feed the queen, the larvae and the males, they exhibit trophallaxis, mauling and ovoposition behavior, and also they protect the colony. The average of lifespan of a worker is 14 days. The males emerge in late July or early August before the emergence of the new queens, finally the colony decline in early September. The parasite Sphecopha vesparum burra is uncommon in the nest of Vespula consobrina, because, the workers are easily disturbed and they tend to inspect all the nest trespassers and they kill them (Akre et al.1982).
This species is common and this is not reported in vulnerability status (Klinkenberg 2010).
Blackjacket are predators and they attack only live prey, they rejected dead bugs. They are mostly predators of small spiders, phalangids, mirids, lygaeids, spittle bugs, house flies, sawflies larvae, caterpillars and smallest grasshoppers. They reject adult butterflies, hard beetles and large hymenopterans. The adults carry their prey or part of them to the nest to feed their larval states. They also feed of flower nectar or sweet substances (Akre et al.1982).
This Nearctic species is widely distributed throughout Canada and Boreal region of North America but not reaching Alaska. In Canada this species is present in all states and territories excluding Nunavut. In United States the species is from northern to south of California, Colorado, Georgia, Illinois, Kentucky, North Dakota, Utah and Wisconsin (GBIF 2011, Buck et al. 2008, Miller 1961).
This species has a unique defensive behavior. When the colony is perturbed the workers flew out and then dropped to the ground, they crawled up onto the invader to sting. The colony defense is variable and it depends of the colony history, for example, several old colonies are quite aggressive but smaller colonies are less aggressive. The members of the colonies are hyperactive and they are in constant motion, the workers have the ability to hover in flight, this behavior which seems adaptive to their usual habits of foraging live prey in low dense vegetation on the ground, this behavior is not reported in other species of Vespula (Akre et al.1982).
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