Honey bees, Apis mellifera L., typically reject pollen of upland cotton, Gossypium hirsutum L., as a resource. This study evaluated the potential of stimulating bees for enhanced pollen collection in overcoming this rejection. In 2002, 16 equal-sized colonies of each of two commercial stocks of bees (Italian and Russian) were placed adjacent to cotton fields at Rosedale, LA, and manipulated so that half of the colonies of each bee type had high stimulus to collect pollen and half had low stimulus. Differential stimuli were achieved by interchanging combs having relatively large amounts of brood with combs having pollen, between colonies of the two treatment groups (i.e., high stimulus colonies donated pollen and received brood, whereas low stimulus colonies had the converse). Stimulus manipulations resulted in more general pollen collection, but not cotton pollen collection, in the high stimulus group on days 1 and 6 after treatment. Foraging responses of the treatment groups equalized by 11 days after treatment. Collection of cotton pollen was minimal (≤2% of all foragers) during this period and was not affected by stimulus treatment. Italian colonies had greater total foraging activity and pollen collection effort on day 1 after treatment, but the bee types foraged similarly on days 6 and 11. There were no interactions of the effects of stimulus treatment and bee type. After the treatment effects dissipated (by day 11, 5 August 2002), collection of cotton pollen increased substantially. Approximately one-fourth of all foragers and 80% of pollen collectors carried cotton pollen pellets during a 2-wk period in midAugust. In 2004, observations of 11 colonies at a cotton planting near Fordoche, LA, showed that foragers again carried notable amounts of cotton pollen during the middle of bloom but little cotton pollen earlier or later. At the peak, a mean of 26% of pollen loads of all colonies and 50–59% of pollen in two colonies were of cotton. The reason for this unexpected willingness to gather cotton pollen is undetermined and warrants investigation because of the potential importance for cotton pollination by honey bees.
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