SCENT MARKING, SCENT ORIGIN, AND SPECIES-SPECIFICITY IN MALE PREMATING BEHAVIOR OF 2 SCANDINAVIAN BUMBLEBEES

The marking behavior and the scent-marking compounds in males of two S candinavian bumblebee species Bombus pratorum and Bombus lapidarius we re studied. There are characteristic differences in the behavior and i n the chemistry of the two species. Males of B. pratorum scent marked small areas of the edges of birch leaves in a quick and unpredictable manner, depositing farnesol, geranylgeranyl acetate, farnesyl acetate, (Z)-11-octadecanol, hexadecanol, and a pentacosadiene. In B. lapidari us, scent marking on birch leaves was much slower and the entire edge of the leaf was marked with (Z)-9-hexadecenol and hexadecanol. These c ompounds were also detected in the cephalic portion of the labial glan d in males. Thus, males of B. lapidarius produce a blend of fatty acid derivatives while B. pratorum males, in addition to fatty acid deriva tives, also produce sesqui- and diterpenes. The total amount of scent compounds per milligram of labial glands was 0.2 mu g in B. pratorum a nd 40 mu g in B. lapidarius. Farnesol and farnesyl acetate were detect ed via headspace collection in the air around leaves marked by B. prat orum and (Z)-9-hexadecenol was detected around leaves marked by B. lap idarius.