Comparison of queen and male production in commercially produced Bombus terrestris L. colonies under the laboratory, greenhouses and wild conditions

Bombus terrestris L. is an important pollinator bee species of wild flora as well as agricultural crops. After the start of the mass production, commercially reared B. terrestris colonies have been used on a large scale for pollination of crops especially greenhouse crops. Shortly after their widely commercial use for pollination, it was recognized that B. terrestris queens (gynes) released from commercial colonies have become established and spread in the wild. This study aimed to obtain the scientific data on the spreading potential of B. terrestris colonies from greenhouses to wild. A total of 45 commercially produced B. terrestris colonies containing one queen and 50 workers were randomly divided into three groups and kept in their natural habitat, greenhouse, and laboratory conditions until the end of colony life span. We determined the reproductive outputs (focusing on the numbers of gynes and gyne pupae produced), the colony weight change and the total number of adult gynes and gyne pupae produced in colonies and compared the groups. Colonies in the laboratory produced (60.27  37.05) on average 3.5 times and 2.5 times more queens (gynes) than colonies in the greenhouse (17.73  8.02) and field (25.00  31.01) respectively. Similarly, laboratory colonies produced significantly more gyne pupae (40.60  15.44) than in the greenhouse colonies (10.73  9.32) (p<0.01). The results show that foraging and quantity and diversity of pollen influence the number of gynes produced. Although greenhouse colonies produced less gynes than laboratory colonies, considering the large quantities of colonies used in greenhouse each year escaping bees from greenhouses could have serious impacts on natural ecosystems. Therefore, effective measures to restrict the escape of males and gynes from greenhouses are needed.