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

Abstract

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 01.24), 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.

Insect Visitors of White Clover (Trifolium Repens L) and Their Relation With Environmental Variables in the Premises of Bhaktapur Multiple Campus, Nepal

“…The most abundant species observed on Trifolium repens was Apis cerana (54.75%) belonging to Hymenoptera order and family Apidae. Similar result has been reported elsewhere (Goodwin et al, 2011). White clover flowers are strongly adapted to bee pollination; hence bees are mostly attracted for nectar (Kevan and Baker, 1983).…”

Wild Pollinators Enhance Fruit Set of Crops Regardless of Honey Bee Abundance

“…By comparison, methods for maintaining diverse wild insects for crop pollination are less developed, and research on such pollination services is more recent (3,16,17,20,26,27) (table S1). Although honey bees are generally viewed as a substitute for wild pollinators (3,(6)(7)(8), our results demonstrate that they neither maximize pollination, nor fully replace the contributions of diverse, wild-insect assemblages to fruit set for a broad range of crops and agricultural practices on all continents with farmland. These conclusions hold even for crops stocked routinely with high densities of honey bees for pollination, such as almond, blueberry or watermelon ( Fig.…”

“…Globally, yields of insect-pollinated crops are often managed for greater pollination through the addition of honey bees (Apis mellifera L.) as an agricultural input ( Fig. 1) (6)(7)(8). Therefore, the potential impact of declines in wild pollinators on crop yields is largely unknown, as is whether increasing application of honey bees (9) compensates for losses of wild pollinators, or even promotes these losses.…”

“…Large, active colonies of honey bees provide abundant pollinators that can be moved as needed, hence their appeal for pollination management in most animal-pollinated crops (6)(7)(8)26). By comparison, methods for maintaining diverse wild insects for crop pollination are less developed, and research on such pollination services is more recent (3,16,17,20,26,27) (table S1).…”

The economic cost of losing native pollinator species for orchard production

“…To satisfy the pollination demand in the absence of native bumblebees and other wild pollinators that provide efficient and sustainable crop pollination services, farmers routinely practice massive supplementations of managed pollinators such as the Western honeybee Apis mellifera L. (Aebi et al, 2012;Geslin, Gauzens, et al, 2017;Goodwin, Cox, Taylor, Evans, & McBrydie, 2011;Rucker, Thurman, & Burgett, 2012). However, this practice might not optimize crop yield as high densities of honeybees at the farm level can result in undesirable outcomes (Rollin & Garibaldi, 2019).…”