Identification and distribution of cross-pollinating honey-bees on almonds.
Foraging by honey bees was studied in 1988 and 1989 in an orchard containing 5 cross-pollinating varieties of almond (Prunus dulcis). Every foraging honey bee collected had self-pollen (same cultivar as the one it was foraging) on its body and at least 90% had cross-pollen (from another cultivar). In both years the majority of bees also carried non-almond pollen. In 1988, 42.1-81.2% of stigmas examined had self-pollen, 36.8-68.7% had cross-pollen, and 43.7-94.0% had non-almond pollen. The corresponding results for 1989 were 60-100%, 10-100% and 80-100%, respectively. Nut set on branches adjacent to compatible pollen sources did not differ significantly from nut set on branches adjacent to trees of the same cultivar. The population of honey bees capable of cross-pollination was apparently a majority of the overall honey bee foraging population and was homogeneously distributed throughout the orchard.