The geometric framework for nutrition reveals interactions between protein and carbohydrate during larval growth in honey bees

Authors: HELM, BRYAN - North Dakota State University; SLATER, GARETT - North Dakota State University; Rajamohan, Arun; Yocum, George; GREENLEE, KENDRA - North Dakota State University; BOWSHER, JULIA - North Dakota State University

Submitted to: Biology Open
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/29/2017
Publication Date: 6/15/2017
Citation: Helm, B.R., Slater, G.P., Rajamohan, A., Yocum, G.D., Greenlee, K.J., Bowsher, J.H. 2017. The geometric framework for nutrition reveals interactions between protein and carbohydrate during larval growth in honey bees. Biology Open. 6(6):872-880. doi:10.1242/bio.022582.

Interpretive Summary: Honey bees (Apis mellifera) are one of the most important and well known pollinators. Additionally they have other economic benefits to mankind such as, honey production. It is well known that of late bees are facing a serious threat of a very complex nature that is still being assessed and studied to be comprehended. In light of this threat, it is imperative that studies to conserve bees be taken up so that they may be released to the field on a later date. Lab rearing of bee embryos and larvae can permit us to produce specific castes of bees including queen bees as well as workers to generate a new colony or to resuscitate a dying colony. Our studies in this report assesses the effects of artificial diet, especially the diet’s carbohydrate and protein components on the development of bee larvae in laboratory conditions. The best growth rate for bee larvae was seen with diets containing moderate amounts of protein and low carbohydrate content. High carbohydrate and low protein contents in the diet negatively affected the bee larval development in vitro.

Technical Abstract: In holometabolous insects, larval nutrition affects adult body size, a life history trait with a profound influence on performance and fitness. Individual nutritional components of larval diet are often complex and may interact with one another, necessitating the use of a geometric framework for understanding nutritional effects. In the honeybee, Apis mellifera, nurse bees provision food to developing larvae, directly moderating growth rates and caste development. However, the eusocial nature of honeybees makes nutritional studies challenging because diet components cannot be systemically manipulated in the hive. Using in vitro rearing, we investigated the roles and interactions between carbohydrate and protein content on larval survival, growth and development in A. mellifera. We applied a geometric framework to understand how these two nutritional components interact across nine artificial diets. Honeybees successfully completed larval development under a wide range of protein and carbohydrate contents, with the medium protein (~5%) diet having the highest survival. Protein and carbohydrate both had significant and non-linear effects on growth rate, with the highest growth rates observed on a medium-protein, low-carbohydrate diet. Diet composition did not have a statistically significant effect on development time. These results confirm previous findings that protein and carbohydrate content affect the growth of A. mellifera larvae. However, this study identified an interaction between carbohydrate and protein content that indicates a low-protein, high-carb diet has a negative effect on larval growth and survival. These results imply that worker recruitment could decline on forage of low protein content if nectar is overly abundant in the diet.