Attractiveness of species of vitex (Chastetree) to pollinators

Abstract

Native and non-native bees are important pollinators of both food and ornamental crops. However, bee populations across the world have declined, mainly through loss of habitat. Careful selection of landscape plants in urban areas can help mitigate habitat loss and create new habitat for pollinators. Ten mature genotypes of Vitex, comprising V. agnus-castus L., V. negundo L., and a hybrid between V. agnus-castus x V. rotundifolia L. f., were evaluated during June and July 2016 to assess their attractiveness to pollinators. Pollinator counts were taken two times daily, at 9:00 a.m. and 11:00 a.m., twice weekly for three weeks. Pollinators were also captured from the Vitex plants for identification. Insects captured from Vitex plants were identified to genus and bumblebees [Bombus spp. (Latreille, 1802)] were further identified to species. Bumblebees and honeybees [Apis mellifera (Linnaeus, 1758)] were more numerous on Vitex plants than carpenter bees. V. agnus-castus plants attracted more bumblebees than honeybees. V. negundo and the V. agnus-castus x V. rotundifolia hybrid attracted more pollinators over the course of the study than V. agnus-castus. Our study shows that Vitex plants can be a good resource to support pollinators in an urban landscape.