Pollen Harvesting Rates for Apis mellifera L. on Gossypium (Malvaceae) Flowers

Pollen harvesting rates were determined for honey bee foragers on flowers of Gossypium thurberi. Foragers visited 2.2-4.8 flowers/minute and collected 0.5-1.0 mg of pollen per minute. Pollen grains are 103-128 μm in diam., moist and sticky, allowing the collection of 894-1778 grains/minute. Pollen collection time was not significantly different for bees that collected only pollen (0.9 ± 0.1, SD, mg/minute) compared to nectar-foragers (0.8 ± 0.2 mg/minute) that passively acquired, then packed pollen. These are apparently the first empirically derived pollen-collecting rates for A. mellifera on any angiosperm. Pollen collection in relation to floral morphological complexity and hidden pollen is also discussed.