Life History Changes in Eastern Mosquitofish (Gambusia holbrooki) Induced by Thermal Elevation

1991 ◽  
Vol 48 (1) ◽  
pp. 60-66 ◽  
Author(s):  
Gary K. Meffe
Keyword(s):  
South Carolina ◽  
Life History ◽  
Nuclear Reactor ◽  
Natural Populations ◽  
Life History Evolution ◽  
Gambusia Holbrooki ◽  
Genetic Changes ◽  
Thermal Death ◽  
Reproductive Biomass ◽  
Eastern Mosquitofish

Much light can be shed on life history evolution through study of responses of organisms to chronic exposure to a novel or perturbed environment. To determine the influence of 28 yr of temporally unpredictable thermal elevation on their life history patterns, I sampled eastern mosquitofish (Gambusia holbrooki) from a thermally elevated (outflow from a nuclear reactor) and an ambient (farm pond) habitat in South Carolina every month for 2 yr. Fish from the artificially heated environment reproduced all year, had higher reproductive investments (higher clutch sizes and reproductive biomass), and smaller offspring than did fish from the ambient environment, which ceased reproduction from October through March, typical for natural populations of the region. Likely environmental factors responsible for these differences include unpredictable food resources, higher mortality from thermal death, and higher predation by fishes and birds in the heated waters. The extent to which these life history alterations are the result of adaptive genetic changes versus phenotypically plastic responses remains to be tested.

Genetic differences in thermal tolerance of eastern mosqyitofish (Gambusia holbrooki; Poeciliidae) from ambient and thermal ponds

1995 ◽  
Vol 52 (12) ◽  
pp. 2704-2711 ◽  
Author(s):  
Gary K. Meffe ◽  
Stephen C. Weeks ◽  
Margaret Mulvey ◽  
K. L. Kandl
Keyword(s):  
Genetic Diversity ◽  
South Carolina ◽  
Genetic Variation ◽  
Thermal Tolerance ◽  
Nuclear Reactor ◽  
Temperature Tolerance ◽  
Gambusia Holbrooki ◽  
Narrow Sense Heritability ◽  
Thermal Maximum ◽  
Eastern Mosquitofish

Two populations of eastern mosquitofish (Gambusia holbrooki; Poeciliidae) in South Carolina, one in an ambient temperature pond and the other in a pond heated to near-lethal temperatures by nuclear reactor effluents for 60–90 mosquitofish generations, offered an excellent opportunity to observe selection for increased thermal tolerance. We performed three experiments. First, we determined the critical thermal maximum of each population and, as predicted, found the thermal population to have a higher one. We then exposed fish from both populations to an acute thermal LD50 stress and compared genetic diversity of fish that died and fish that survived. Survivors had higher heterozygosities, indicating that genetic diversity may contribute to thermal tolerance. Finally, we used a half-sib – full-sib experimental design to estimate heritabilities for temperature tolerance in fish from the heated pond. We calculated a narrow-sense heritability for temperature at death of over 32%, indicating that selection has not depleted the population of genetic variation associated with thermal tolerance. Our results have implications for climate change because adaptations to higher thermal regimes must, in part, come from selection on genetic variation for temperature tolerance within populations.

scholarly journals Kinship dynamics: patterns and consequences of changes in local relatedness

2021 ◽  
Vol 288 (1957) ◽  
pp. 20211129
Author(s):  
Darren P. Croft ◽  
Michael N. Weiss ◽  
Mia L. K. Nielsen ◽  
Charli Grimes ◽  
Michael A. Cant ◽  
...  
Keyword(s):  
Life History ◽  
Social Evolution ◽  
Inclusive Fitness ◽  
Natural Populations ◽  
Life History Evolution ◽  
The Mean ◽  
The Individual ◽  
Changes Over Time ◽  
Insight Into ◽  
Over Time

Mounting evidence suggests that patterns of local relatedness can change over time in predictable ways, a process termed kinship dynamics. Kinship dynamics may occur at the level of the population or social group, where the mean relatedness across all members of the population or group changes over time, or at the level of the individual, where an individual's relatedness to its local group changes with age. Kinship dynamics are likely to have fundamental consequences for the evolution of social behaviour and life history because they alter the inclusive fitness payoffs to actions taken at different points in time. For instance, growing evidence suggests that individual kinship dynamics have shaped the evolution of menopause and age-specific patterns of helping and harming. To date, however, the consequences of kinship dynamics for social evolution have not been widely explored. Here we review the patterns of kinship dynamics that can occur in natural populations and highlight how taking a kinship dynamics approach has yielded new insights into behaviour and life-history evolution. We discuss areas where analysing kinship dynamics could provide new insight into social evolution, and we outline some of the challenges in predicting and quantifying kinship dynamics in natural populations.

scholarly journals Telomeres: Linking stress and survival, ecology and evolution

2010 ◽  
Vol 56 (6) ◽  
pp. 714-727 ◽  
Author(s):  
Mark F. Haussmann ◽  
Nicole M. Marchetto
Keyword(s):  
Oxidative Stress ◽  
Life History ◽  
Stress Response ◽  
Current Knowledge ◽  
Natural Populations ◽  
Life History Evolution ◽  
Cellular Aging ◽  
Cellular Mechanisms ◽  
Telomere Biology ◽  
Protective Structures

Abstract Telomeres are protective structures at the ends of eukaryotic chromosomes. The loss of telomeres through cell division and oxidative stress is related to cellular aging, organismal growth and disease. In this way, telomeres link molecular and cellular mechanisms with organismal processes, and may explain variation in a number of important life-history traits. Here, we discuss how telomere biology relates to the study of physiological ecology and life history evolution. We emphasize current knowledge on how telomeres may relate to growth, survival and lifespan in natural populations. We finish by examining interesting new connections between telomeres and the glucocorticoid stress response. Glucocorticoids are often employed as indices of physiological condition, and there is evidence that the glucocorticoid stress response is adaptive. We suggest that one way that glucocorticoids impact organismal survival is through elevated oxidative stress and telomere loss. Future work needs to establish and explore the link between the glucocorticoid stress response and telomere shortening in natural populations. If a link is found, it provides an explanatory mechanism by which environmental perturbation impacts life history trajectories.

Sign in / Sign up

Export Citation Format

Share Document