title: Analysis of pollen and nectar of Arbutus unedo as a food source for Bombus terrestris (Hymenoptera: Apidae).
abstract: The mineral, total amino acid, and sterol compositions of pollen collected by Apis mellifera L. were compared with the pollen of a plant consumed by Bombus terrestris (L.): Arbutus unedo L. This plant provides the predominant food resource for the main autumn generation of B. terrestris in southern France. Honey bees also forage on this plant, although only for nectar. The mineral composition of 30 pollen samples collected by honey bees is close to the presently known requirements of A. mellifera, except for Cu and Mn, which are substantially lower. The total amino acid mean composition of a set of 54 pollen samples fits the basic requirements of honey bees except for valine, isoleucine, and methionine, which are present in lower concentrations in all the samples. For pollen of A. unedo, the amino acid balance is not very different from that of the survey. The main sterolic component in pollen of A. unedo, beta-sitosterol, is known to have antifeedant effects on A. mellifera. Honey bees cannot dealkylate C29 sterols like beta-sitosterol or delta5-avenasterol to obtain C27 cholesterol and ecdysteroids. Because these phytosterols as well as cholesterol are nearly absent from pollen of A. unedo, the metabolic capabilities of Apis seem unadapted to this plant. On the contrary, pollen of A. unedo is freely consumed by B. terrestris, which develops huge autumn populations solely on this food. These data indicate that the sterolic metabolisms of B. terrestris and A. mellifera differ, allowing separation in foraging activity.
authors: Université de Mons-Hainaut, B-7000 Mons, Belgium. pierre.rasmont@umh.ac.be
authors: Pierre
authors: P
authors: Rasmont
authors: Ariane
authors: A
authors: Regali
authors: Thomas C
authors: TC
authors: Ings
authors: Georges
authors: G
authors: Lognay
authors: Evelyne
authors: E
authors: Baudart
authors: Michel
authors: M
authors: Marlier
authors: Emile
authors: E
authors: Delcarte
authors: Pascal
authors: P
authors: Viville
authors: Cécile
authors: C
authors: Marot
authors: Pol
authors: P
authors: Falmagne
authors: Jean-Claude
authors: JC
authors: Verhaeghe
authors: Lars
authors: L
authors: Chittka
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001516:Bees / Q000502:physiology*; D004032:Diet; D029791:Ericaceae / Q000737:chemistry*; D008903:Minerals / Q000032:analysis; D011058:Pollen / Q000737:chemistry*; D013261:Sterols / Q000032:analysis
chemical_list: D000596:Amino Acids; D008903:Minerals; D013261:Sterols