Don’t overeat: nurse honey bees practice strict protein-lipid regulation

Authors: Lau, Pierre; LESNE, PIERRE - Texas A&M University; PAYNE, ALEXANDRIA - US Department Of Agriculture (USDA); GARCIA, CORA - Texas A&M University; GOMEZ, JORDAN - Texas A&M University; BEHMER, SPENCER - Texas A&M University; RANGEL, JULIANA - Texas A&M University

Submitted to: Proceedings of the Royal Society. B. Biological Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/25/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary: As generalist pollinators, honey bees collect food from many different flowering plants that together meet the nutrition required for optimal growth, development, and overall health at the individual and colony level. For bees, pollen is the source of proteins and lipids and, nectar, the source of carbohydrates. One of the factors that can explain the challenges faced by bees is habitat-quality-mediated poor nutrition, which is directly related to the reduction in the diversity of flowering plants in a landscape. However, what constitutes poor nutrition is not adequately defined and whether bees can regulate intake based on nutrient composition is not well understood. Studies applying the Geometric Framework for Nutrition to honey bees have focused on protein and carbohydrate regulation. In this study, aimed at determining whether nurse bees can regulate dietary intake of proteins and lipids, we demonstrate maximum consumption of diet containing 30% protein and 20% lipid. The study also showed that nurse bees may be regulating their lipid intake more than their protein intake, as they stopped consuming the diet once their lipid threshold was reached. These results highlight the ability of bees to regulate intake based on nutrient composition and can be applied towards the development of relevant supplementary diets for honey bee colonies.

Technical Abstract: Nutrition is foundational for all animals, and the Geometric Framework for Nutrition (GFN) has greatly advanced our understanding of animal nutrient regulation. For honey bees (Apis mellifera), reported losses of managed colonies is often linked to poor nutrition, but what constitutes poor nutrition for honey bees is not adequately defined. To date, honey bee nutrition has mostly focused on protein-carbohydrate intake and regulation. In contrast, we know relatively little about protein-lipid intake and regulation, even though pollen has high, but variable, protein-lipid content. Using GFN-designed no-choice and choice experiments, we show how nurse bees – tasked with feeding developing brood – regulate their protein-lipid intake. These experiments show that nurses eat most from diets containing 30% protein and 20% lipid, produce the largest hypopharyngeal glands on this diet, and generally regulate to this 1.5:1 protein-lipid ratio when given two nutritionally complementary protein-lipid diets. However, our experiments also reveal that nurses stop feeding once they reach their protein or lipid threshold. This “strict restraint” rule suggests that, for nurses, there is likely a cost of overeating protein or lipid. Our findings highlight the importance of dietary lipids in honey bee nutrition, which has direct implications for bee management and, more broadly, for palynivore nutritional ecology.