Plant a Rose Today to Conserve the World’s Most Important Solitary Bee

Abstract

Pollinator conservation is a global priority. Efforts are taken to restore pollinators by improving flower resources, a crucial driver of pollinator diversity and population. It gave a facelift to gardening and landscaping supply chains, which introduced lists of bee-friendly plants and bee hotels, yet, desirable results seem distant. One shortcoming of the present schemes is the lack of a cohesive planning for nesting opportunities and nesting provisions for the wild solitary bees, the crucial pollinators of crops and wild plants. We tested whether the world’s most favourite ornamental plant, Rose (Rosa chinensis Jacq.) – a hitherto unlisted bee-friendly plant – can aid conserving leafcutter bees, which require fresh leaves for constructing nest cells. We surveyed 2,360 Rose plants in 136 sites in rural and urban places and lowlands and highlands of south (8oN – 12oN) and northeastern India (26oN-27oN) for the characteristic notches the bees leave on foraged leaves. Potted Rose plants were sprayed with the contact pesticides to study the effect of pesticide on bee foraging of leaves. Broods constructed by the Rose leaves were reared to examine the brood success rate. About a quarter of all the Roses surveyed had the notches of leafcutter bees on the leaves. However, the proportion of cut Roses varied considerably among and between sites. Bees used Roses heavily in cities and lowlands over villages and highlands. Selection of plants was negatively associated with pesticide treatment. Brood success rate was 100%. Rose flowers do not support bees, but Rose leaves do. We recommend Rose plants in pollinator conservation and restoration schemes.