Foraging Behaviour of Floral Visitors as an Indicator of Pollination Potential in Sweet Cherry Orchards

Abstract

Sweet cherry production relies heavily on managed and wild insect pollinators. Pollination success depends not only on the presence of flower visitors but also on their behaviour and traits. Although Chile is among the world's leading cherry producers, information on the diversity and pollination roles of insect visitors in its orchards remains scarce. In this study, we used video monitoring to assess the foraging behaviour of floral visitors in 16 conventional orchards in central Chile. In 2023, we recorded 3012 insect visits. Bees comprised 65% of visits, with honey bees (Apis mellifera) alone accounting for 64% and fewer than 1% for wild bees. Besides, 33% of the visits were attributed to flies—mainly Dilophus sp. (Bibionidae) and several syrphid species—and 2% to beetles. Bees spent the shortest time per flower, exhibited greater inter-floral movement and contacted the stigma most frequently, behaviours associated with high pollination potential. In contrast, flies and beetles typically remained longer on flowers, moved little between them and often consumed floral resources without making contact with the stigma. These behavioural patterns suggest that hymenopterans are the most effective pollinators in these systems. Nevertheless, the high abundance of flies in the orchards may partly compensate for their limited pollination efficiency. Additionally, we found a significant positive relationship between body size and the likelihood of stigma contact, highlighting a key morphological trait associated with pollination effectiveness. The overall low diversity and small size of floral visitors in these conventional cherry orchards may explain why few of the species present have the potential to be effective pollinators. Promoting practices that enhance bee floral visitor diversity could increase the presence of alternative pollinators, reduce reliance on managed honeybees and contribute to more stable cherry yields.