Reed bee (Exoneura spp.) pollination efficiency and nesting preferences in a Rubus berry orchard in the Yarra Valley, Australia

Abstract

Agricultural pollination services are largely reliant upon the European honeybee (Apis mellifera), a species which is seeing global declines. Native bees have the potential to act as agricultural pollinators, to diversify and add resilience to current honeybee-reliant pollination services. However, little is currently known about the potential for Australian native bees to act as efficient crop pollinators. My thesis examines the role that the reed bee (Exoneura spp.) and white-banded bee (Lasioglossum (Chilalictus)) spp.) might play in pollinating a Rubus crop, and whether the reed bee in particular will nest in this crop. Single-visit pollination data and nesting preference data were collected in the spring of 2019 at a berry orchard in the Yarra Valley, Victoria, Australia. I found that reed bees and white-banded bees were equally efficient in pollinating blackberries (Rubus fruticosus sp. agg.) as honeybees, and were associated with a three-fold increase in drupelet set compared to the control group. I also found that reed bees will willingly nest within a raspberry (Rubus idaeus) crop in large numbers (mean estimate of 3,320 bees per hectare), and that they show preferences towards narrow and more upright stems when choosing a suitable nest. These findings suggest that reed bees show promise as a Rubus pollinator, and exhibit nesting behaviors that may enable land managers to increase reed bee numbers across their properties. This research helps to provide the basis for the management of this genus and highlights avenues for future research. Show more