The Effect of Climate and Diet on Body Lipid Composition in the Oriental Hornet (Vespa orientalis)

Abstract

Fatty acids (FA) are the primary metabolic fuel for many organisms and the fundamental component of membranes of all living organisms. FAs can be saturated (SFA), monounsaturated (MUFA), or polyunsaturated (PUFA). PUFA are not synthesized by most animals and are considered as essential nutrients. We examined the effect of climate on the saturation level of polar (mostly membranal) and neutral lipids in the body of the Oriental hornet (Vespa orientalis) from two extreme climatic zones: Mediterranean high elevation; and hot arid desert. In contrast to previous reports, the environmental temperature was shown to affect the hornet colonies’ thermal environments. The hornets nonetheless maintained their colony temperature within a narrow range. Analyses of the hornets’ unsaturation levels of polar and non-polar body lipids revealed caste differences: gynes and males contained less unsaturated lipids than workers. However, there were no differences in the respective castes between the two different climate zones tested. Experimentally manipulating the diet of queenless hornet colonies to a high Omega-3 diet (salmon) or a high Omega-6 diet (crickets) had only a minor effect on the worker-born males’ lipid composition. Although salmon-fed males had a higher Omega-3 content than cricket-fed ones, the proportion of these fatty acids was still low (below 1%). Cricket-fed males had significantly higher levels of Omega-6 than salmon-fed males. Our data show that the specific lipid composition of the hornet body is highly regulated and deficient in essential PUFA, even under different climates or high Omega-3 or Omega-6 PUFA diet. PUFA, especially Omega-3, is considered to have a beneficial effect on physiological processes. Our finding that these FA, when common in the diet, are almost absent in the body raises questions about how they affect animals’ physiology.

Body size, metabolic rate and diapause in the oriental hornet (Vespa orientalis), in two extreme climatic regions

“…Although climate affects the thermal environment of the colony, the Oriental hornet can maintain its nest temperature within a relatively narrow range. We previously found no biochemical adaptations in the membranes of these hornets in different climates, as the lipid composition in the Oriental hornet remained highly conserved even under extreme climates and diet manipulations; still, significant differences in polar (assumed to be membrane originated) and non‐polar lipid saturation levels were found between the different hornet castes (Volov et al, 2021).…”

The Effect of Temperature and Nutrient on Developmental Biology and Physiology of Stored-Product Species of Coleoptera

“…Therefore, their amount of carbohydrate and protein content affects the amount of lipids and fatty acids. Lipids consist of fatty acids and have important functions in living organisms [77][78][79].…”

“…Linoleic and linolenic acids and their long-chain metabolites are precursors of eicosanoids, which play an important role in insect physiology. Eicosanoids affect reproduction, cellular immunity and thermoregulation [79,109,113]. Insects can convert 18 C polyunsaturated fatty acids to 20 C polyunsaturated fatty acids biochemically [79].…”

“…Eicosanoids affect reproduction, cellular immunity and thermoregulation [79,109,113]. Insects can convert 18 C polyunsaturated fatty acids to 20 C polyunsaturated fatty acids biochemically [79]. Since eicosanoids, which play an important role in insects, can be synthesized from different fatty acids, these fatty acids can be found in small amounts in important role as hormones, pheromones and defensive secretions in the immune mechanism and reproduction of insects [81].…”

Nutrient Utilization during Male Maturation and Protein Digestion in the Oriental Hornet

“…Our animal model, the Oriental hornet, is a notorious predator of honeybees, naturally distributed throughout the Mediterranean Basin, the Middle East, Arabia, and India [15,16]. As the only Vespa species that occurs in deserts [17], it is well adapted to warm, arid habitats; accordingly, it is prevalent in the Israeli desert and temperate, high-elevated Mediterranean regions [18]. Oriental hornets form annual colonies in the spring that develop rapidly during the summer, and produce up to two thousand individuals by the beginning of autumn when reproductives emerge; males usually emerge before their nestmate-queens and disperse to copulate with queens from other colonies in a nuptial flight [19].…”