Resumen

TORRETTA, Juan P.; MEDAN, Diego; ROIG ALSINA, Arturo  y  MONTALDO, Norberto H.. Diurnal floral visitors of sunflower (Helianthus annuus, Asterales: Asteraceae) in Argentina. Rev. Soc. Entomol. Argent. [online]. 2010, vol.69, n.1-2, pp. 17-32. ISSN 1851-7471.

Sunflower (Helianthus annuus L.) is an important oilseed crop in Argentina. During three agricultural years, the diversity and abundance of diurnal floral visitors of sunflower heads were determined in eight sites spanning much of this crop's cultivation area in Argentina. Seventysix morpho-species of floral visitors, belonging to eight orders, were captured on sunflower. The principal order was Hymenoptera, with 37 species or morpho-species, of which 32 were bees (Apoidea). The most represented bee families were Apidae (13), Megachilidae (11) and Halictidae (7). The domestic bee (Apis mellifera L.) accounted for 93% of the visits. Floral visitor composition did not show an identifiable variation pattern either throughout the day or with respect to the distance to the edge of the crop, but varied among sites. It is concluded that the domestic bee is the main sunflower pollinator in Argentina, although several native bee species (Melissodes tintinnans (Holmberg), M. rufithorax Brèthes, Melissoptila tandilensis Holmberg, and Megachile spp.) could be considered as potential crop pollinators.

Palabras llave : Apis mellifera; Melissodes; Native bees; Pollination.