Bombus spp. (species of the genus Bombus). This bee genus comprises 262 Bombus spp. grouped in 15 subgenus worldwide, but only three (Bombus argillaceus, Bombus terrestris and Bombus niveatus) in Palestine and wider area. Most commonly known in English as bumblebees, these big bees are typically found in temperate climates and often live in high latitudes and altitudes. However, a few species can also be found in the tropics and lowland. One reason for their presence in cold places is the capacity to regulate their body temperature, by shivering their muscles and via sunlight. They can absorb hit even from a weak sunshine.
Bumblebees vary in their sizes, even within species. The largest European bumblebee is the queen of Bombus terrestris, with up to 22 mm long. However, the largest bumblebee species in the world is Bombus dahlbomii in Chile, measuring up to about 40 mm long and it is in risk of extinction. Bombus spp. vary also in appearance, not only among different species, but between individuals of different geographic regions, belonging to the same species. In general, they have a round and densely furry body, with different colours patterns between queen and workers and between female and male. Bombus spp. are social insects, forming colonies under the control of a queen. The colonies are, however, smaller than honeybee’s hives, comprising much less individuals in a nest. Actually, nest size depends on the Bombus species. Most colonies have between 50 and 400 individuals, but there are reports of a colony of 1700 individuals. Moreover, female bumblebees can sting repeatedly, without hurting themselves, since their sting has no bars, like in honeybees. Their tongue is long, with tinning hairs and is kept folded under the head during the flight. The longer the tongue, the deeper the bee can go into the flower and drink nectar. A long tongue is especially good for foraging on flowers with a tube corolla.
There exist parasitoid species of Bombus. These do not make nests. Instead, parasitoid queens aggressively invade the nests of other Bombus species, kill the resident queens and lay their own eggs, which are cared for by the host workers.