Insufficient and excessive Ca intake negatively impact the life history performance and disrupt the hemolymph metabolism of Spodoptera litura.

Calcium ions (Ca), essential as second messengers in all cells, play a pivotal role as micronutrients in insects. However, few studies have explored the effects of both insufficient and excessive Ca intake on life history performance and population parameters. This study examines the impact of varying Ca intake levels-insufficient (0 mg/kg), appropriate (100 mg/kg), and excessive (250 mg/kg)-on the life history performance and population parameters of Spodoptera litura using two-sex life tables. Insufficient and excessive Ca intakes significantly extended the preadult development period and decreased the preadult survival rates of S. litura, compared to those on an appropriate Ca intake. The population parameters (Intrinsic rate of increase (r), Finite rate of increase (λ), and Net reproductive rate (R)) of S. litura on a 100 mg/kg diet (r = 0.1364, λ = 1.1462, R = 390) were significantly higher than those on a 0 mg/kg diet (r = 0.1091, λ = 1.1153, R = 130.52). Additionally, untargeted metabolomics analysis revealed that inappropriate Ca levels (either insufficient or excessive) triggered significant up-regulation of 71.1 % and 92.8 % of the metabolites in the hemolymph, respectively, compared to the appropriate Ca intake. Notably, disruptions in metabolite balance affected critical components such as melatonin and melanin within the tryptophan and tyrosine metabolism pathways. These findings underscore that both insufficient and excessive Ca intakes adversely affect the life history performance and disrupt hemolymph metabolic balance in S. litura.