scholarly journals Predation and Resource Availability Interact to Drive Life-History Evolution in an Adaptive Radiation of Livebearing Fish

2021 ◽  
Vol 9 ◽  
Author(s):  
Kaj Hulthén ◽  
Jacob S. Hill ◽  
Matthew R. Jenkins ◽  
Randall Brian Langerhans

Predation risk and resource availability are two primary factors predicted by theory to drive the evolution of life histories. Yet, disentangling their roles in life-history evolution in the wild is challenging because (1) the two factors often co-vary across environments, and (2) environmental effects on phenotypes can mask patterns of genotypic evolution. Here, we use the model system of the post-Pleistocene radiation of Bahamas mosquitofish (Gambusia hubbsi) inhabiting blue holes to provide a strong test of the roles of predation and resources in life-history evolution, as the two factors do not co-vary in this system and we attempted to minimize environmental effects by raising eight populations under common laboratory conditions. We tested a priori predictions of predation- and resource-driven evolution in five life-history traits. We found that life-history evolution in Bahamas mosquitofish largely reflected complex interactions in the effects of predation and resource availability. High predation risk has driven the evolution of higher fecundity, smaller offspring size, more frequent reproduction, and slower growth rate—but this predation-driven divergence primarily occurred in environments with relatively high resource availability, and the effects of resources on life-history evolution was generally greater within environments having high predation risk. This implies that resource-driven selection on life histories overrides selection from predators when resources are particularly scarce. While several results matched a priori predictions, with the added nuance of interdependence among selective agents, some did not. For instance, only resource levels, not predation risk, explained evolutionary change in male age at maturity, with more rapid sexual maturation in higher-resource environments. We also found faster (not slower) juvenile growth rates within low-resource and low-predation environments, probably caused by selection in these high-competition scenarios favoring greater growth efficiency. Our approach, using common-garden experiments with a natural system of low- and high-predation populations that span a continuum of resource availability, provides a powerful way to deepen our understanding of life-history evolution. Overall, it appears that life-history evolution in this adaptive radiation has resulted from a complex interplay between predation and resources, underscoring the need for increased attention on more sophisticated interactions among selective agents in driving phenotypic diversification.

2006 ◽  
Vol 29 (3) ◽  
pp. 288-289
Author(s):  
Peter Kappeler

The proposition that selective advantages of linguistic skills have contributed to shifts in ontogenetic landmarks of human life histories in early Homo sapiens is weakened by neglecting alternative mechanisms of life history evolution. Moreover, arguments about biological continuity through sweeping comparisons with nonhuman primates do not support various assumptions of this scenario.


1974 ◽  
Vol 108 (964) ◽  
pp. 805-817 ◽  
Author(s):  
Henry M. Wilbur ◽  
Donald W. Tinkle ◽  
James P. Collins

2009 ◽  
Vol 364 (1523) ◽  
pp. 1499-1509 ◽  
Author(s):  
Shripad Tuljapurkar ◽  
Jean-Michel Gaillard ◽  
Tim Coulson

Environmental stochasticity is known to play an important role in life-history evolution, but most general theory assumes a constant environment. In this paper, we examine life-history evolution in a variable environment, by decomposing average individual fitness (measured by the long-run stochastic growth rate) into contributions from average vital rates and their temporal variation. We examine how generation time, demographic dispersion (measured by the dispersion of reproductive events across the lifespan), demographic resilience (measured by damping time), within-year variances in vital rates, within-year correlations between vital rates and between-year correlations in vital rates combine to determine average individual fitness of stylized life histories. In a fluctuating environment, we show that there is often a range of cohort generation times at which the fitness is at a maximum. Thus, we expect ‘optimal’ phenotypes in fluctuating environments to differ from optimal phenotypes in constant environments. We show that stochastic growth rates are strongly affected by demographic dispersion, even when deterministic growth rates are not, and that demographic dispersion also determines the response of life-history-specific average fitness to within- and between-year correlations. Serial correlations can have a strong effect on fitness, and, depending on the structure of the life history, may act to increase or decrease fitness. The approach we outline takes a useful first step in developing general life-history theory for non-constant environments.


2021 ◽  
Vol 8 ◽  
Author(s):  
Andrea J. Roth-Monzón ◽  
Mark C. Belk ◽  
J. Jaime Zúñiga-Vega ◽  
Jerald B. Johnson

Life-history traits are directly linked to fitness, and therefore, can be highly adaptive. Livebearers have been used as models for understanding the evolution of life histories due to their wide diversity in these traits. Several different selective pressures, including population density, predation, and resource levels, can shape life-history traits. However, these selective pressures are usually considered independently in livebearers and we lack a clear understanding of how they interact in shaping life-history evolution. Furthermore, selective pressures such as interspecific competition are rarely considered as drivers of life-history evolution in poeciliids. Here we test the simultaneous effects of several potential selective pressures on life-history traits in the livebearing fish Poeciliopsis prolifica. We employ a multi-model inference approach. We focus on four known agents of selection: resource availability, stream velocity, population density, and interspecific competition, and their effect on four life-history traits: reproductive allocation, superfetation, number of embryos, and individual embryo size. We found that models with population density and interspecific competition alone were strongly supported in our data and, hence, indicated that these two factors are the most important selective agents for most life-history traits, except for embryo size. When population density and interspecific competition increase there is an increase in each of the three life-history traits (reproductive allocation, superfetation, and number of embryos). For individual embryo size, we found that all single-agent models were equivalent and it was unclear which selective agent best explained variation. We also found that models that included population density and interspecific competition as direct effects were better supported than those that included them as indirect effects through their influence on resource availability. Our study underscores the importance of interspecific competitive interactions on shaping life-history traits and suggests that these interactions should be considered in future life-history studies.


Ecology ◽  
2001 ◽  
Vol 82 (6) ◽  
pp. 1546-1559 ◽  
Author(s):  
Gregory F. Grether ◽  
David F. Millie ◽  
Michael J. Bryant ◽  
David N. Reznick ◽  
Wendy Mayea

1986 ◽  
Vol 64 (4) ◽  
pp. 875-884 ◽  
Author(s):  
Catherine A. Tauber ◽  
Maurice J. Tauber

Geographical patterns of variation among North American populations of Chrysoperla carnea provide strong evidence that ecophysiological traits are central to the evolution of life histories. Selection pressure and the types and amounts of genetic variability underlying the traits vary geographically. Western populations exhibit considerable genetic variability in their reproductive responses to both photoperiod and prey. This variability is expressed both at the interpopulation level by the diversity of locally adapted populations and at the intrapopulation level in the form of genetic polymorphisms. By contrast, eastern, midwestern, and northwestern regions contain two types of reproductively isolated, monomorphic populations. The two types differ in their photoperiodic requirements for reproduction, but neither uses prey as a cue to stimulate reproduction. Although most of the characteristic responses to photoperiod and prey can vary independently of each other, the separate traits tend to covary to form coadaptive sets. The covariance of a few responses appears to have a genetic or physiological basis, a condition that places constraints on the evolution of life histories. Our results also demonstrate that comparative studies at the intraspecific level are highly significant to the analysis of life-history evolution and to the taxonomic treatment of species complexes.


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