Pollen composition significantly impacts the development and survival of the native small carpenter bee, Ceratina calcarata

Abstract

As native bee populations decrease, there is a need to better understand their nutritional requirements to sustain healthy pollinator populations. A common native bee to eastern North America is the small carpenter bee, Ceratina calcarata. Previous studies have shown that the primary pollen sources for C. calcarata consist of clover and rose. The aim of this study is to compare the effects of diet composition on body size, development and survival. Artificial pollen diets were created using five different ratios of commercially available clover and rose pollen. Diets containing higher ratios of clover pollen produced larger individuals with increased survival rates and faster development times. To examine this further, the macronutrient profiles of clover and rose pollen were characterised comparing: protein, sugar, fatty acid, and amino acid content. Results indicated that rose pollen contained significantly higher protein and sugar content, while clover pollen had higher concentrations of essential amino acids. These are crucial to bee health and development, which helps to explain the increased survivorship observed on high clover diet treatments. Taken together, these results show that clover pollen provides a higher quality diet for larval development and survival of the native small carpenter bee. This research indicates that diet has a significant effect on the health of the native pollinator community and more research is needed to further explore the balance between pollen quality and availability, including essential macronutrients and the availability of these floral sources for wild bees.