Restriction of nutrients in the adult diet extends lifespan across a diverse range of species, but less is known about the long-term effects of developmental dietary restriction. In particular, it is not known whether adult lifespan is influenced by developmental caloric restriction or macronutrient balance. We used the nutritional geometry approach to independently manipulate protein and carbohydrate contents of the larval diet in the neriid fly, Telostylinus angusticollis, and measured adult lifespan. We found that adult male and female lifespan was shortest when larvae were fed a protein restricted diet. Thus, protein restriction in the larval diet has the opposite effect of protein restriction in the adult diet (which prolongs life in this species and across a wide range of taxa). Adult lifespan was unaffected by larval dietary carbohydrate. These patterns persisted after controlling for larval diet effects on adult body size. We propose that larval and adult protein sources are used for distinct metabolic tasks: during development, dietary protein is used to build a durable soma that enhances adult lifespan, although excessive protein consumption partially reverses this effect.

1. Although the ecological and evolutionary importance of environmentally induced parental effects is now widely recognized, such effects are still typically studied by contrasting just two environments in a single parental sex. Yet, parental effects should generally be viewed as reaction norms, and a more complete understanding of their ecological role therefore requires examining continuously varying and interacting environmental variables in both parental sexes. 2. We used nutritional geometry to investigate linear, nonlinear and interactive effects of protein and carbohydrate in maternal and paternal larval diets on offspring juvenile development and viability and adult body size and shape in the fly Telostylinus angusticollis (Diptera: Neriidae). 3. We found that egg hatching success was enhanced by protein in the maternal larval diet but reduced by protein in the paternal larval diet, while other juvenile traits were unaffected by parental diets. 4. Maternal effects on offspring adult body size and head elongation (a secondary sexual trait in males) were mediated by linear and quadratic effects of protein, and were consistent in sons and daughters. In contrast, paternal effects on offspring body size and head elongation were mediated by carbohydrate effects or carbohydrate─protein interactions, and varied by offspring sex. 5. Our findings show that macronutrients in the parental larval diet can have complex, nonlinear and interactive effects on offspring traits, and that the effects of maternal and paternal diets can be strikingly different. Effects of parental diet on offspring represent important fitness consequences of variation in nutrient intake, with potential implications for the evolution of foraging and reproductive strategies.

The lace bug genus Cottothucha is redescribed. Cottothucha kalathis from Australia is described as new to science. The fifth instar for C. kalathis is described and illustrated. Cottothucha minor and Cottothucha oceanae are redescribed. The male genitalia of these species are illustrated. The pronotal cyst is compared between the species and its evolution is discussed. The genus is maintained within the lace bug tribe Litadeini based on an enlarged tarsal segment.