Sex-specific phenotypic plasticity in response to the trade-off between developmental time and body size supports the dimorphic niche hypothesis

Abstract

Female-biased sexual size dimorphism (SSD) is widespread in many invertebrate taxa. One hypothesis for the evolution of SSD is the dimorphic niche hypothesis, which states that SSD evolved in response to the different sexual reproductive roles. While females benefit from a larger body size by producing more or larger eggs, males benefit from a faster development, which allows them to fertilize virgin females (protandry). To test this hypothesis, we studied the influence of temperature and intraspecific density on the development of the grasshopper, Chorthippus montanus. We reared them in monosexual groups under different conditions and measured adult body size, wing length, nymphal mortality, and development time. The present study revealed an inverse temperaturesize relationship: body size increased with increasing temperature in both sexes. Furthermore, we found intersexual differences in the phenotypic response to population density, supporting the dimorphic niches hypothesis. At a lower temperature, female development time increased and male body size decreased with increasing density. Because there was no food limitation, we conclude that interference competition hampered development. By contrast to expectations, mortality decreased with increasing density, suggesting that interference did not negatively affect survival. The present study shows that sex-specific niche optima may be a major trigger of sexual dimorphisms.

Climate‐related geographical variation in performance traits across the invasion front of a widespread non‐native insect

“…Body size is a fundamental life‐history trait that is positively correlated with an array of other fitness‐related traits (Chown & Gaston, 2010). Across taxa with complex life cycles, intraspecific variation in size at metamorphosis is often driven by trade‐offs with development time, where selection for a shorter larval development time can result in smaller adult body sizes (Nylin & Gotthard, 1998; Rohde et al., 2015). However, despite increased pupal mass at warmer temperatures, we found no biologically meaningful relationship between source climate and development time, with differences in development time less than 1–2 days among populations within a rearing temperature.…”

Evidence of hatch-time based growth compensation in the early life history of two salmonid fishes

“…Early phenotype can establish individuals on trajectories towards alternative life histories, and influences factors such as morphology, growth, and reproduction (Taborsky 2006;Jonsson and Jonsson 2014;Walsh et al 2015;Rohde et al 2015;Clarke et al 2016).…”

“…Early phenotype can establish individuals on trajectories towards alternative life histories, and influences factors such as morphology, growth, and reproduction (Taborsky 2006; Jonsson and Jonsson 2014; Walsh et al 2015; Rohde et al 2015; Clarke et al 2016). In turn, phenology (timing) of reproductive events such as germination, hatch, or birth affects early phenotypes (Beer & Anderson, 2001; Brännäs, 1995; Einum & Fleming, 2000; Sternecker, Denic, & Geist, 2014).…”

Sexual size dimorphism and Rensch's rule in Canidae

“…MBSSD is mostly attributed to the action of sexual selection because a larger body size of males would be favoured in intrasexual competition and/or preferential female choice (Trivers, 1972;Dale et al, 2007). FBSSD is widespread in invertebrates and ectothermic vertebrates, although some mammal species show this bias (Bidau & Marti, 2008a;Bidau, Marti & Castillo, 2013;De Lisle & Rowe, 2013;Liao et al, 2013;Rohde, Dreher & Hochkirch, 2015). Multiple causes for FBSSD have been suggested in different species.…”

“…Subsequent to Darwin's (1871) publication of The Descent of Man and Selection in Relation to Sex, SSD has been considered the result of sexual selection (Trivers, 1972;Andersson, 1994;Dale et al, 2007). However, other explanations may apply if natural selection favoured different body sizes to suit differential niche utilization or if competition for food occurs between both sexes (Selander, 1966;Hedrick & Temeles, 1989;Shine, 1989;Andersson, 1994;Isaac, 2005;Meiri, Dayan & Simberloff, 2005;Rohde et al, 2015). Nevertheless, niche divergence between sexes is not necessarily independent of differentiation of reproductive roles in males and females (Hedrick & Temeles, 1989;Shine, 1989;Fairbairn, 2007).…”