Effects of dietary fatty acids and carotenoids on the body composition of the brown marmorated stink bug

Abstract Halyomorpha halys – a hemipteran insect – has been reported to have nutritional benefits as an edible insect. Although we previously observed that field-collected adults are rich in polyunsaturated fatty acids, the effects of diet on their fatty acid composition remain unclear. Although most animals acquire carotenoids through their diet, hemipteran insects may possess a unique ability to biosynthesise carotenoids independently or through their endosymbionts. In this study, we assessed the effects of four diets – almonds, peanuts, soybeans, and sunflower seeds – on the fatty acid composition and carotenoid content of H. halys . The proportion of palmitic and stearic acids in their bodies remained relatively stable regardless of the diet, whereas that of linoleic and α -linolenic acids varied based on the diet. This indicates that fatty acid composition is regulated by internal and external factors, as reported for various insects. Additionally, we observed that H. halys likely accumulates lutein obtained from its diet. In contrast, β -carotene and astaxanthin were absent in both the diets and insect bodies. Therefore, we observed no evidence that this hemipteran insect can acquire carotenoids independent of its diet. The regulation of fatty acid composition and carotenoid metabolism in H. halys appears to be similar to that in other insects.