Nutrition during sexual maturation affects competitive ability but not reproductive productivity in burying beetles

Abstract

Summary1. Food availability can be unpredictable. When food becomes more abundant following a period of low food availability, developing larvae or juveniles often allocate resources preferentially towards increasing growth. This has important long-term effects on adult phenotypes and longevity. Despite the importance of strategic resource allocation during early development, few studies have examined how changes in resource availability during other windows of development affect reproductive strategies and fitness independent of growth. 2. We manipulated food availability in a burying beetle, Nicrophorus vespilloides, during a subadult period of sexual maturation when individuals cannot increase structural size but are still undergoing reproductive maturation. 3. In contrast to the trade-offs during larval or juvenile growth, beetles that experienced delayed feeding during reproductive maturation allocated resources preferentially towards maintaining both reproductive function and longevity. 4. In both sexes, delayed feeding beetles were much less successful in competition for carcasses. However, delayed feeding males and females provided similar amounts of parental care and did not differ in reproductive success or longevity. 5. These results indicate that the nutritional environment experienced during a key developmental window may be an important determinant of the expression of alternative reproductive strategies in adulthood, independent of body size.

Behavioral plasticity and G × E of reproductive tactics inNicrophorus vespilloidesburying beetles

“…Our results confirm that relative competitive ability in burying beetles is largely determined by body size (Otronen ; Hopwood et al , ; Lee et al ), which is itself primarily determined by parental response to variation in the resources available to beetles during the larval stage (i.e., carcass size; Bartlett and Ashworth ; Eggert and Müller ). Therefore, behavioral plasticity of signaling behavior in male N. vespilloides also depends upon developmental plasticity of individuals in response to variation in carcass size.…”

“…This generated variation in the social environment experienced by focal males; from good (focal male larger than competitor) to poor (focal male smaller than competitor). Previous work has shown that relative male size is the most important determinant of contest outcomes over carcasses (Hopwood et al , 2014; Lee et al ). Our experimental design replicated what is likely to happen in the wild, where there is uncertainty about the size of competitors that males will encounter in competition for breeding resources (Hopwood et al ).…”

“…Competitor males were given a white mark on the top of their pronotum to facilitate male identification. Marking does not affect behavior (Hopwood et al ).…”

Niche variation and the maintenance of variation in body size in a burying beetle

“…Newly captured beetles were cleared of phoretic mites in the field (by blowing the mites off beetles using a sharp exhalation of breath directed through pursed lips). To ensure beetles were sexually mature and to reduce individual variation in nutritional status before their use in experiments, all captured beetles were housed individually in the laboratory as described in previous experiments (Hopwood et al ., ) and fed with two decapitated mealworms, Tenebrio molitor https://en.wikipedia.org/wiki/Carolus_Linnaeus, twice per week. Laboratory beetles in experiment 2 were all used on day 8 after capture; beetles used for experiment 1 were used between 7 and 13 days after capture owing to logistical constraints in the field.…”

Effects of resource variation during early life and adult social environment on contest outcomes in burying beetles: a context-dependent silver spoon strategy?

“…Recent studies have demonstrated the importance of the timing of nutritional deprivation on success in adulthood [19,20], which may have independent or interactive effects on the expression of adult phenotypes. Distinct stages may often exist in the developmental processes of organisms when nutritional variation has disproportionately large effects on phenotypic expression [21], including effects on disease susceptibility in later life [22] and adaptive polyphenisms, such as the winged phase switch in pea aphids, Acyrthosiphon pisum [23] or horn elongation in dung beetles, e.g.…”