Physiological mechanisms underlying the costs of chemical defence in Junonia coenia Hu¨bner (Nymphalidae): A gravimetric and quantitative genetic analysis

摘要: Several recent studies document that specialist insect phytophages may be less subject to predation than generalists and suggest hostplant-derived chemical defences an important explanation for the predominance of specialized feeding among herbivores. The evolution such depends upon both their advantages versus natural enemies physiological costs, but data on these particularly genetic data, are few. Here I report results ecological investigation food use efficiency allelochemical sequestration in Junonia coenia Hu¨bner (Nymphalidae). used standard gravimetric techniques estimate dry matter incorporation iridoid glycoside larvae 37 full-sib families fed artificial diets containing trace, low (2%) high (10%) concentrations glycosides. found a significant reduction diet is entirely attributable reduced digestibility rather post-digestive toxic effects. Larvae high-iridoid sequestered them efficiently, this difference was due largely Analyses variation architecture budgets reveal substantial suites traits, only defence showed genotype×environment interaction which would conducive specialization. Neither group traits across-diet trade-offs form negative correlations family means diets. Family indices with within reveals comes at cost growth, diet. also evidence machinery processing. These indicate even adapted specialists negatively affected by plant toxins, species, dietary specialization more likely result from selection hostplant toxins.