Psithyrus Variabilis

	Psithyrus Variabilis ''Bombus variabilis'' is a critically endangered species of Psithyrus, cuckoo bumblebee that occurs in North America. It has not been observed in the United States in at least 20 years and is potentially extirpated or extinct. ''Bombus variabilis'' is a parasitic species. Females kill and replace the queens of ''Bombus pensylvanicus, B. pensylvanicus'', taking over their nests in the process. The decline of the latter as hosts can partially be linked to the decline of ''B. variabilis''. This species of bee can be distinguished by the lack of pollen baskets. The bee features have a dark face with yellow hair in its vertex and with dark brown wings. Its thorax has variations between black spots or patches. For females, they only have black abdomens but males can vary in their hair color patterns. References Bumblebees Insects described in 1872 {{bombus-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon]
	Ezra Townsend Cresson Ezra Townsend Cresson (18 June 1838, in Byberry19 April 1926, in Swarthmore) was an American entomologist who specialized in the Hymenoptera order of insects. He wrote ''Synopsis of the families and genera of the Hymenoptera of America, north of Mexico'' Philadelphia: Paul C. Stockhausen, Entomological printer (1887) and many other works. Cresson also documented many new species including ''Nomada texana''. In 1859, Cresson founded the Entomological Society of Philadelphia, together with James Ridings and George Newman. The society was later renamed to the American Entomological Society in 1867. Two of his sons, George Bringhurst Cresson (1859–1919) and Ezra Townsend Cresson, Jr. (1876–1948), were also entomologists and members of the American Entomological Society. George B. Cresson was a general naturalist and specialist in ants, and Ezra T. Cresson Jr. was a specialist in Diptera Flies are insects of the order Diptera, the name being derived from the Greek δ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon]
	Psithyrus Cuckoo bumblebees are members of the subgenus ''Psithyrus'' in the bumblebee genus '' Bombus''. Until the 1990s, ''Psithyrus'' was considered to constitute a separate genus.Williams, P.H. 1994. Phylogenetic relationships among bumblebees (''Bombus'' Latr.): A reappraisal of morphological evidence. Systematic Entomology 19: 327-344. They are a specialized socially parasitic lineage which parasitises the nests of 'true' bumblebees; they do not collect pollen or establish their own nests. Cuckoo bumblebees do not create a worker caste and produce only male and female reproductives. They are considered inquilines in the colonies of 'true' bumblebees. Cuckoo bumblebee females emerge from hibernation later than their host species to ensure that their host has had sufficient time to establish a nest. Before finding and invading a host colony, a ''Psithyrus'' female feeds directly from flowers until her ovaries are sufficiently developed, at which time she begins seeking a nest to inva ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon]
	Bombus Pensylvanicus ''Bombus pensylvanicus'', the American bumblebee, is a threatened species of bumblebee native to North America. It occurs in eastern Canada, throughout much of the Eastern United States, and much of Mexico.Hatfield, R., et al. 2015''Bombus pensylvanicus''.The IUCN Red List of Threatened Species. Downloaded on 09 March 2016. Once the most prevalent bumblebee in the southern United States, populations of ''Bombus pensylvanicus'' have decreased significantly in recent years, including in its scientific namesake state of Pennsylvania, where its numbers are considered critically low. Overall, the population dropped nearly 90% in just the first two decades of the 21st century. ''Bombus pensylvanicus'' tends to live and nest in open farmland and fields. It feeds on several food plants, favoring sunflowers and clovers, and functions as a pollinator. Taxonomy and phylogenetics ''Bombus pensylvanicus'' belongs to the order Hymenoptera (consisting of ants, wasps, bees, and sawflies), the f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon]
picture info	Bumblebees A bumblebee (or bumble bee, bumble-bee, or humble-bee) is any of over 250 species in the genus ''Bombus'', part of Apidae, one of the bee families. This genus is the only Extant taxon, extant group in the tribe Bombini, though a few extinct related genera (e.g., ''Calyptapis'') are known from fossils. They are found primarily in the Northern Hemisphere, although they are also found in South America, where a few lowland tropical species have been identified. European bumblebees have also been introduced to New Zealand and Tasmania. Female bumblebees can sting repeatedly, but generally ignore humans and other animals. Most bumblebees are eusociality, social insects that form colony (biology), colonies with a single queen. The colonies are smaller than those of honey bees, growing to as few as 50 individuals in a nest. Psithyrus, Cuckoo bumblebees are brood parasite, brood parasitic and do not make nests or form colonies; their queens aggressively invade the nests of other bumble ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon]