Dietary choice for a balanced nutrient intake increases the mean and reduces the variance in the reproductive performance of male and female cockroaches

Abstract

Sexual selection may cause dietary requirements for reproduction to diverge across the sexes and promote the evolution of different foraging strategies in males and females. However, our understanding of how the sexes regulate their nutrition and the effects that this has on sex‐specific fitness is limited. We quantified how protein (P) and carbohydrate (C) intakes affect reproductive traits in male (pheromone expression) and female (clutch size and gestation time) cockroaches (Nauphoeta cinerea). We then determined how the sexes regulate their intake of nutrients when restricted to a single diet and when given dietary choice and how this affected expression of these important reproductive traits. Pheromone levels that improve male attractiveness, female clutch size and gestation time all peaked at a high daily intake of P:C in a 1:8 ratio. This is surprising because female insects typically require more P than males to maximize reproduction. The relatively low P requirement of females may reflect the action of cockroach endosymbionts that help recycle stored nitrogen for protein synthesis. When constrained to a single diet, both sexes prioritized regulating their daily intake of P over C, although this prioritization was stronger in females than males. When given the choice between diets, both sexes actively regulated their intake of nutrients at a 1:4.8 P:C ratio. The P:C ratio did not overlap exactly with the intake of nutrients that optimized reproductive trait expression. Despite this, cockroaches of both sexes that were given dietary choice generally improved the mean and reduced the variance in all reproductive traits we measured relative to animals fed a single diet from the diet choice pair. This pattern was not as strong when compared to the single best diet in our geometric array, suggesting that the relationship between nutrient balancing and reproduction is complex in this species.

Effects of macronutrient intake on the lifespan and fecundity of the marula fruit fly, Ceratitis cosyra (Tephritidae): Extreme lifespan in a host specialist

“…Using the GF approach, similar results were found in Nauphoeta cinerea , where females had a low protein requirement for reproduction (Bunning et al., 2016). Interestingly, N. cinerea is also known to have a particularly long lifespan of up to 3 years in the laboratory (Moore & Moore, 2001).…”

“…Bunning et al. (2016) suggested that the low protein requirement for reproduction in N. cinerea females was potentially due to their capacity to store excess protein as nitrogen through endosymbiotic interactions. Hence, if females had access to a protein source as juveniles, it might have been possible for them to restore this protein stock when fed on low P:C diet in their adult stage.…”

“…(2015) and Bunning et al. (2016). In brief, we used a multivariate response surface approach to estimate the linear and nonlinear (interactions between P × P, C × C, and P × C) effects of P and C on response variables (LS, LEP, DEP) for each sex.…”

Little evidence for intralocus sexual conflict over the optimal intake of nutrients for life span and reproduction in the black field cricketTeleogryllus commodus

“…The diets chosen to form the four diet pairs were diets 2, 4, 22, and 24 (pair 1: diets 2 and 22; pair 2: diets 2 and 24; pair 3: diets 4 and 22; pair 4: diets 4 and 24), and are the same diets as those used in the choice feeding experiments of Bunning et al. () and Rapkin et al. ().…”

You are what you eat: diet shapes body composition, personality and behavioural stability

“…1). One may, by contrast, also expect the opposite pattern, for example, when low-quality dietary environments represent relatively novel environmental conditions where additional (‘cryptic’) genetic variance is expressed [29], leading to decreased among-individual variance under high-quality dietary conditions (e.g., [14, 30, 31]).…”