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Is flower selection influenced by chemical imprinting to larval food provisions in the generalist bee Osmia bicornis (Megachilidae)?

Dobson, Heidi E. M., Ayasse, Manfred, O’Neal, Katherine A., Jacka, Jesse A.
Apidologie 2012 v.43 no.6 pp. 698-714
Brassica napus, Onobrychis viciifolia, Osmia rufa, adults, females, flowers, larvae, males, nesting, rearing, solitary bees
To investigate whether flower selection in polylectic solitary bees is modulated by chemical imprinting to nest provisions, larvae of Osmia bicornis (L.) were reared on either Brassica napus L. (Brassicaceae) or Onobrychis viciifolia Scop. (Fabaceae). Flower preferences by adults were evaluated in multiple-choice behavioral tests based on visit number and duration, and flowers selected in the first three visits; data were compared to control bees from the wild. Females reared on B. napus showed only subtle increases in selection for this species, which was highly attractive to both control and experimental bees, masking any effects of imprinting; however, in the first three visits, experimental bees tended to select B. napus more frequently and consistently than controls. Bees reared on O. viciifolia were few and mostly males, which tended to visit this species more than controls. Rearing larvae on either plant affected bee attraction to other plant species. Overall, the data do not provide clear evidence of imprinting, but suggest that rearing bees on a single plant can both directly and indirectly affect flower selection by adults.