Development of hives for field population increase, and studies on the life cycles of the four species of introduced bumble bees in New Zealand

Abstract

From 1971-73, of 340 field nest boxes and hives 84 (24.7%) were occupied by all 4 introduced bumble bee spp. in New Zealand. Field-collective and induced nests were similar in bee productivity. Reproductive nests of Bombus hortorum and B. terrestris produced form 2-5 times as many individuals as did nests of the same 2 spp. in Europe. The increase in New Zealand is due to the absence of all but 3 of their enemies present in Europe, the lack of endemic New Zealand enemies and freedom from food competition by other bee species. Nests of these 2 spp. were established throughout most of the year. Nests of B. ruderatus and B. subterraneus were similar in production of total individuals to nests of the same 2 spp. in Europe; nests were founded only in spring and summer. Competition for food from the other 2 spp. may limit nest size. Only 32 (38.1%) of the induced nests produced new queens. Nest mortality was greatest when the foundress queens disappeared or died in the nest (52.4%). In 3 seasons, the number of new queens produced by reproductive nests was 12.4 times greater than the number of queens (100) involved in founding all 84 nests. Future hives should allow for better drainage and should be constructed of more durable materials. Prospects for increasing populations of bumble bees in New Zealand by use of simply constructed field-placed hives are excellent.