Alternative intrapopulation life‐history strategies and their trade‐offs in an African annual fish

Abstract

In ephemeral habitats, the same genotypes cope with unpredictable environmental conditions, favouring the evolution of developmental plasticity and alternative life-history strategies (ALHS). We tested the existence of intrapopulation ALHS in an annual killifish, Nothobranchius furzeri, inhabiting temporary pools. The pools are either primary (persisting throughout the whole rainy season) or secondary (refilled after desiccation of the initial pool), representing alternative niches. The unpredictable conditions led to the evolution of reproductive bet-hedging with asynchronous embryonic development. We used a common garden experiment to test whether the duration of embryonic period is associated with post-embryonic life-history traits. Fish with rapid embryonic development (secondary pool strategy, high risk of desiccation) produced phenotypes with more rapid life-history traits than fish with slow embryonic development (primary pool strategy). The fast fish were smaller at hatching but had larger yolk sac reserves. Their post-hatching growth was more rapid, and they matured earlier. Further, fast fish grew to a smaller body size and died earlier than slow fish. No differences in fecundity, propensity to mate or physiological ageing were found, demonstrating a combination of plastic responses and constraints. Such developmentally related within-population plasticity in life history is exceptional among vertebrates.

The African turquoise killifish: A research organism to study vertebrate aging and diapause

“…The accumulation of damage from the passage of time is likely blocked or attenuated in this dormant state. Importantly, while the majority of embryos obligatorily enter diapause, some embryos naturally skip diapause and exhibit a continuous lifecycle, probably as a hedge‐betting evolutionary mechanism (Polacik et al., 2014; Furness, Lee & Reznick, 2015, and C.‐K. Hu and A. Brunet, unpublished data ).…”

Convergent evolution of alternative developmental trajectories associated with diapause in African and South American killifish

“…Whether following different developmental pathways has lasting effects on post-hatching phenotype, or if the developmental system has effectively buffered embryos from potential negative consequences of remaining dormant for long periods has recently been addressed. Polacik et al [52] have shown that the developmental pathway followed has significant effects on fishes' post-hatching life histories. Darwin [7] proposed that adaptive diversification is the product of selection and the conservation of some life stages relative to others may be a by-product of the reduced role that natural selection has played in shaping some phases of development.…”

Life-history plasticity in female threespine stickleback

“…DeWitt and Langerhans (2004) expand on this idea by differentiating between constitutive and plastic aspects of integrated phenotypes. The effect of plasticity, and the degree to which plasticity in one trait may be linked to plasticity in other traits, depends upon the limits of plasticity in each trait (Polačik et al, 2014), and the forms of the functions relating specific trait values to fitness, modified by the effects of body size, somatic condition (Reznick and Ghalambor, 2001;Ghalambor et al, 2007), density (Leips et al, 2009) and perhaps growth rate. The increase in maternal fitness derived from a plastic response (for example, increased offspring survival or growth) should equal or exceed the expected loss because of negatively correlated traits (for example, the egg-size vs clutch-size tradeoff).…”