Our recent paper “What you eat matters: Nutrient inputs alter the metabolism and neuropeptide expression in Egyptian cotton leaf worm, Spodoptera littorolis (Lepidoptera: Noctuidae)” accepted for publication in Frontiers in Physiology focuses on the outcome of different feeding regimes on metabolism. Diets directly affect lipid and carbohydrate metabolism, and bad eating habits are known to induce various important disorders, such as obesity, diabetes, and fatty liver syndrome. Insects are promising models to understand the physiological and biochemical background of these disorders, however, most studies are based on a single model species, Drosophila melanogaster, and each study focus on a particular biological aspect, such as developmental parameters, or lipid/carbohydrate levels, or endocrine regulation. In the current study, we followed an integrated approach and examined multiple parameters at the same time using a new insect model, the Egyptian cotton leaf worm, Spodoptera littorolis (Lepidoptera: Noctuidae) in order to understand the effect of diets on metabolism. Here, we present the effects of different diets, high-fat (HFD), high-sugar (HSD), calcium-rich (CRD) and plant-based, (PBD) on S. littoralis in terms of its developmental biology, lipid and carbohydrate metabolism in relation to four major neuropeptides, the adipokinetic hormone, insulin-like peptide 1, insulin like peptide 2, and the orexigenic short neuropeptide F. The parameters we examined include expression patterns of four neuropeptide genes by Real-time PCR, body weights, triglyceride (TG) levels, trehalose levels, lipid droplet imaging and size detection by confocal microscopy both at 3rd (younger) and 5th instars (older) larvae; as well as larval developmental periods from neonate towards pupal stage at these four different diet types. Both HSD and HFD led to increased weight gain, while CRD led to a reduced weight gain, and PBD did not alter the weight gain. Larval development was shortest with HSD, while HFD led to a significant retardation, and CRD and PBD led to moderate retardations. TG levels were higher with HFD, HSD, and PBD with larger lipid droplets, while CRD led to a reduction at TG levels and lipid droplet size. Trehalose levels were highest in HSD, while CRD led to a reduction in 3rd instar larvae. There was no diet effect on trehalose levels in 5th instar larvae. No difference was detected in the expression of SpoliAKH and SpoliILP1-2 between diets in 3rd instar larvae, while all three genes were primarily expressed with HSD, and SpolisNPF was expressed 5th instar larvae fed HFD. In summary, different diet treatments alter the development of insects, and energy and metabolic pathways through regulation of peptide hormones! So what you eat matters!
For the paper, please click here.
With an Impact Factor of 4.566, Frontiers in Physiology is the 2nd most cited Physiology journal in the world.
