What Drives Life-History Variation in the Livebearing Fish Poeciliopsis prolifica? An Assessment of Multiple Putative Selective Agents

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.

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

Frontiers in Ecology and Evolution ◽

10.3389/fevo.2021.619277 ◽

2021 ◽

Vol 9 ◽

Author(s):

Kaj Hulthén ◽

Jacob S. Hill ◽

Matthew R. Jenkins ◽

Randall Brian Langerhans

Keyword(s):

Life History ◽

Predation Risk ◽

Resource Availability ◽

Life Histories ◽

A Priori ◽

Life History Evolution ◽

Selective Agents ◽

Two Factors ◽

High Predation ◽

History Evolution

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.

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The evolution of human life course

The Oxford Handbook of Human Symbolic Evolution ◽

10.1093/oxfordhb/9780198813781.013.10 ◽

2021 ◽

Author(s):

Francesco Suman

Keyword(s):

Life History ◽

Phenotypic Plasticity ◽

Life History Traits ◽

Homo Sapiens ◽

Human Life ◽

Life History Evolution ◽

Extended Evolutionary Synthesis ◽

Genetic Accommodation ◽

Selective Pressures ◽

Life History Pattern

Homo sapiens’ life history pattern possesses both fast and slow components, in a combination that is unique among the extant great apes. One of the issues debated in current evolutionary research is the role played by phenotypic plasticity as a non-genetic means of adaptation to evolutionary challenges. While life history parameters are shaped at a species level by genetic adaptations via natural selection, they remain very sensitive to changes in the environment. Relying on updated evidence and on key explanatory tools of the Extended Evolutionary Synthesis (phenotypic plasticity, niche construction, and inclusive inheritance), it is likely that environmentally induced plasticity led the way in human life history evolution, promoting subsequent genetic accommodation. To the extent that culturally transmitted behaviors altered the selective pressures that acted on life history traits across generations during human evolution, a culturally driven plasticity dynamic shaping human life history traits can be identified. Two case studies in particular are discussed: the human adaptations to the domestication of fire and the self-domestication hypothesis.

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Environmental Certainty, Trophic Level, and Resource Availability in Life History Evolution

The American Naturalist ◽

10.1086/282956 ◽

1974 ◽

Vol 108 (964) ◽

pp. 805-817 ◽

Cited By ~ 133

Author(s):

Henry M. Wilbur ◽

Donald W. Tinkle ◽

James P. Collins

Keyword(s):

Life History ◽

Trophic Level ◽

Resource Availability ◽

Life History Evolution ◽

History Evolution

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Intraspecific heritable variation in life-history traits can alter the outcome of interspecific competition among insect herbivores

Basic and Applied Ecology ◽

10.1016/j.baae.2005.06.003 ◽

2006 ◽

Vol 7 (3) ◽

pp. 215-223 ◽

Cited By ~ 7

Author(s):

S.P. Hazell ◽

I.A.D. McClintock ◽

M.D.E. Fellowes

Keyword(s):

Life History ◽

Interspecific Competition ◽

Life History Traits ◽

Insect Herbivores ◽

Heritable Variation

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Mammalian body size is determined by interactions between climate, urbanization, and life history traits

10.22541/au.160630927.76985045/v1 ◽

2020 ◽

Author(s):

Maggie Hantak ◽

Bryan McLean ◽

Daijiang Li ◽

Robert Guralnick

Keyword(s):

Life History ◽

Body Size ◽

Resource Availability ◽

Life History Traits ◽

Species Traits ◽

Size Change ◽

Resource Availability Hypothesis ◽

Urban Heat ◽

Thermal Buffering ◽

Urbanization Gradients

Anthropogenically-driven climate warming is a hypothesized driver of animal body size reductions. Less understood are effects of other human-caused disturbances on body size, such as urbanization. We compiled 140,499 body size records of over 100 North American mammals to test how climate and urbanization, and their interactions with species traits, impact body size. We tested three hypotheses of body size change across urbanization gradients; urban heat island effects, fragmentation, and resource availability. Our results unexpectedly demonstrate urbanization is more tightly linked with body size changes than temperature, most often leading to larger individuals, thus supporting the resource availability hypothesis. In addition, life history traits, such as thermal buffering, activity time, and average body size play critical roles in mediating the effects of both climate and urbanization on intraspecific body size trends. This work highlights the value of using digitized, natural history data to track how human disturbance drives morphological change.

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Isolation and predation drive gecko life-history evolution on islands

Biological Journal of the Linnean Society ◽

10.1093/biolinnean/blz187 ◽

2020 ◽

Vol 129 (3) ◽

pp. 618-629

Author(s):

Rachel Schwarz ◽

Yuval Itescu ◽

Antonis Antonopoulos ◽

Ioanna-Aikaterini Gavriilidi ◽

Karin Tamar ◽

...

Keyword(s):

Life History ◽

Life Histories ◽

Life History Traits ◽

Life History Evolution ◽

Reproductive Traits ◽

Predation Pressure ◽

Ecological Studies ◽

Island Populations ◽

Island Syndrome ◽

Insular Populations

Abstract Insular animals are thought to be under weak predation pressure and increased intraspecific competition compared with those on the mainland. Thus, insular populations are predicted to evolve ‘slow’ life histories characterized by fewer and smaller clutches of larger eggs, a pattern called the ‘island syndrome’. To test this pattern, we collected data on egg volume, clutch size and laying frequency of 31 Aegean Island populations of the closely related geckos of the Mediodactylus kotschyi species complex. We tested how predation pressure, resource abundance, island area and isolation influenced reproductive traits. Isolation and predation were the main drivers of variation in life-history traits. Higher predator richness seemed to promote faster life histories, perhaps owing to predation on adults, whereas the presence of boas promoted slower life histories, perhaps owing to release from predation by rats on the eggs of geckos. Insular geckos followed only some of the predictions of the ‘island syndrome’. Predation pressure seemed to be more complex than expected and drove life histories of species in two opposing directions. Our results highlight the importance of considering the identity of specific predators in ecological studies.

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Selection is stronger in early-versus-late stages of divergence in a Neotropical livebearing fish

Biology Letters ◽

10.1098/rsbl.2015.1022 ◽

2016 ◽

Vol 12 (3) ◽

pp. 20151022 ◽

Cited By ~ 6

Author(s):

Spencer J. Ingley ◽

Jerald B. Johnson

Keyword(s):

Life History ◽

Life History Traits ◽

Single Point ◽

Evolutionary Trajectory ◽

Trait Evolution ◽

The Difference ◽

Livebearing Fish ◽

Late Stages ◽

Over Time

How selection acts to drive trait evolution at different stages of divergence is of fundamental importance in our understanding of the origins of biodiversity. Yet, most studies have focused on a single point along an evolutionary trajectory. Here, we provide a case study evaluating the strength of divergent selection acting on life-history traits at early-versus-late stages of divergence in Brachyrhaphis fishes. We find that the difference in selection is stronger in the early-diverged population than the late-diverged population, and that trait differences acquired early are maintained over time.

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