Author
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Danka, Robert |
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Submitted to: Journal of Entomological Science
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 11/29/2004 Publication Date: 7/1/2005 Citation: Danka, R.G. 2005. High Levels of Cotton Pollen Collection Observed for Honey Bees (Hymenoptera: Apidae) in South-Central Louisiana. Journal of Entomological Science 40(3):316-326 Interpretive Summary: Yield of upland cotton may increase by 3-30% following pollination by honey bees. However, honey bees only rarely collect cotton pollen in most regions of the USA and this behavior probably restricts their pollination effectiveness. We tried to increase cotton pollen collection in two genetic strains of bees (Italian and Russian bees) by stimulating colonies; stimulation consisted of adding bee brood and removing previously stored pollen. Despite being located adjacent to a large planting of cotton in south Louisiana that was beginning to bloom in late July, collection of cotton pollen was low (<2% of all pollen) by both bee types. After the conclusion of the test, however, we recorded a substantial increased in cotton pollen, particularly during mid August when about 80% of all pollen gathered was from cotton. This is the highest rate of upland cotton pollen collection recorded for honey bees, but the cause of this shift in bee behavior remains undetermined. Because of decreased insecticide use on cotton in the southeastern USA, safe beekeeping opportunities (and thus potential pollination input by bees) are increasing. Documentation of the ability of honey bees in this region to collect cotton pollen warrants further research into the factors that regulate such behavior. Technical Abstract: Honey bees, Apis mellifera, typically reject pollen of upland cotton as a resource. Stimulating bees for enhanced pollen collection may help overcome this rejection. Sixteen 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 received brood and donated pollen, while 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, August 5, 2002), cotton pollen income increased substantially. Approximately one-fourth of all foragers and 80% of pollen collectors carried cotton pollen pellets during a 2-week period in mid August. The reason for this dramatic shift to gathering of cotton pollen is undetermined and warrants investigation because of the potential importance for cotton pollination by honey bees. |
