Temporal patterns of nutrition dependence in secondary sexual traits and their varying impacts on male mating success

Abstract

Variation in the quantity of nutrients ingested over an individual's lifetime is likely to differentially affect distinct male secondary sexual traits and courtship signals, potentially providing females with information about a male's past and present foraging history. We hypothesize that female choice is thus influenced by a male's lifetime foraging history. To test this, we manipulated the quantity of nutrients (i.e. prey items) available to male wolf spiders, Schizocosa stridulans, using a fully crossed 2 × 2 design with low versus high prey quantity across juvenile and adult life stages, and assessed the impact of these diet treatments on male foreleg pigmentation, courtship rate and mating success. We found foreleg pigmentation to be dependent upon both juvenile and adult diet, with increased nutrition dependence of pigmented versus unpigmented leg segments. Despite this, the degree of foreleg pigmentation did not predict mating success. In contrast, courtship rate was not nutrient dependent, yet strongly predicted mating success. Finally, we found a significant interaction between juvenile diet, adult diet and courtship rate on mating success. Males that experienced a diet switch (low juvenile to high adult, LH; high juvenile to low adult, HL) exhibited no relationship between courtship rate and mating success, while those that experienced a consistent diet (LL; HH) showed increased mating success with increased courtship rates. Our results suggest that nutrition dependence of secondary sexual traits is not necessarily a predictor of their role in mating success and that female mate choice is the result of complex interactions between multiple male traits.