Number of honey bee visits required to fully pollinate white clover (Trifolium repens) seed crops in Canterbury, New Zealand

摘要

White clover (Trifolium repens L.) is grown throughout New Zealand in pasture and as a seed crop in the South Island. This investigation was conducted to determine the number of honey bee visits necessary to fully pollinate white clover flowers; the number of foraging honey bees per hectare required to reach the maximum seed number per floret; and to assess the level of white clover pollination in Canterbury. The theoretical maximum number of seeds that can be produced per white clover floret is six, based on the number of ovules present. Based on the number of seeds resulting from a single bee visit (mean = 1.24), it is calculated that in an 8 h foraging day, 19,420 bees would be required per hectare to reach maximum seed number per floret, assuming that no floret received more visits than required. Bee activity was assessed at two clover sites with an estimated 20,124 foraging bees per hectare. This number should have been enough to reach maximum seed number per floret. However, seed set in these fields was approximately half of its theoretical potential.