Abstract:Lipids have a key role in a variety of physiological functions in insects including energy, reproduction, growth and development. Whereas most of the required fatty acids can be synthesized endogenously, omega-3 and omega-6 polyunsaturated fatty acids (PUFA) are essential fatty acids that must be acquired through nutrition. Honey bees (Apis mellifera) obtain lipids from pollen, but different pollens vary in nutritional composition, including of PUFAs. Low floral diversity and abundance may expose bees to nutritional stress. We tested the effect of total lipids concentration and their omega-6:3 ratio on aspects of honey bee physiology: brood development, adult longevity and body fatty acids composition. All three parameters were affected by dietary lipid concentration and omega-6:3 ratio. Higher lipid concentration in diet increased brood production, and high omega-6:3 ratio increased mortality rate and decreased brood rearing. Fatty acid analysis of the bees showed that the amount of lipids and the omega-6:3 ratio in their body generally reflected the composition of the diet on which they fed. Consistent with previous findings of the importance of a balanced omega-6:3 ratio diet for learning performance, we found that such a balanced PUFA diet, with above threshold total lipid composition, is also necessary for maintaining proper colony development.