Pollen harvest by solitary bees (Ptilothrix relata, Hym. Apidae, Emphorini) in the Argentine pampas - preliminary results

Abstract

In order to determine the plants foraged by solitary Ptilothrix relata, the pollen content of food provisions was identified. The main pollen types confirm foraging by these bees on Malvaceae, Asteraceae and Onagraceae. Pollen sources belonging to Cucurbitaceae, Dipsacaceae and Portulacaceae families enrich the harvesting range of P. relata. According to the preliminary results, these bees can be considered more as narrowly polylectic than oligolectic because they collect pollen from a few unrelated species. Among the most abundant pollen collected, two major morphological types were recognized: (1) pollen with long spines (4-25 μm), many single apertures and large size (115-135 μm of diameter); and (2) tricolporate pollen with viscin threads.