Ecology of Species of Bombus Latr. (Hymenoptera: Apidae) in Southern Alberta. I. Subgenus Alpinobombus Skor.

Abstract

AbstractIn southern Alberta the range of Bombus (Alpinobombus) balteatus was limited to mountainous areas with minimum elevations of 7,400 ft. When given equal opportunity to nest in above- or underground hives, queens established in two above, and 12 underground hives. The middle of the nest-establishing period in the hives was about 24 June 1962, and 17 June 1963.Construction of the brood cell was begun before that of the honey pot. All eggs of the first brood were deposited in n single cell; not all were deposited on the same day. Second- and third-brood egg cells were built in parallel lines on each side of the incubation groove. At least once, the second brood was also workers. Succeeding broods were probably first males and then queens, as males emerged first.Pollen was fed collectively to worker larvae of all instars, except the last, by stuffing it beneath them. All instars of male and queen larvae, except the last, were fed collectively mixtures of honey and pollen. Last-instar larvae of all broods separated from each other by spinning flimsy, incomplete cocoons, and were fed individually mixtures of honey and pollen. Hence, B. balteatus is a pocket-maker when rearing worker larvae to the last instar and a pollen-storer when rearing last-instar worker, male, and queen larvae.