Honey bees are essential for pollination of Vitellaria paradoxa subsp. paradoxa (Sapotaceae) in Burkina Faso

Abstract

Shea (Vitellaria paradoxa) is an important fruit tree in West African parklands, and its successful pollination is a requirement for fruit production. Size-based pollinator exclusion experiments combined with visual observations showed that presence of honey bees (Apis mellifera jemenitica) was important for pollination and thereby the production of fruits and seeds. Smaller insects, mainly species of stingless bees (Hypotrigona spp. and Liotrigona cf. bottegoi) and solitary bees (Compsomelissa borneri) could partly compensate pollination in absence of honey bees, but fertilisation and fruit yield was reduced. A positive correlation between fertilisation percentage and number of honey bee colonies within radii of 900 and 1000 m was observed. The percentage of fertilisation and number of mature fruits per fascicle were higher in trees with colonies of stingless bees in the trunk when honey bees were excluded by bagging. We conclude that local beekeeping with honey bees and stingless bees is likely to have a positive influence on fruit production of shea trees in the farmed West African parklands, which speaks in favour of a pollinator friendly environment.