The contribution of abiotic and biotic factors to spatial and temporal variation in population density of the least killifish, Heterandria formosa

Macrae, Pamela S. D.; Travis, Joseph

doi:10.1007/s10641-013-0117-7

Cited by 13 publications

(31 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…If anything, our variation in density was less than the variation seen among populations (Leips & Travis, 1999;MacRae & Travis, 2014;Richardson et al, 2006) and so, were we to extrapolate to natural conditions, we may have underestimated the strength of the effect of social density. If anything, our variation in density was less than the variation seen among populations (Leips & Travis, 1999;MacRae & Travis, 2014;Richardson et al, 2006) and so, were we to extrapolate to natural conditions, we may have underestimated the strength of the effect of social density.…”

Section: Discussionmentioning

confidence: 88%

The effects of food level and social density on reproduction in the Least Killifish, Heterandria formosa

Leatherbury

Travis

2018

Ecology and Evolution

Self Cite

View full text Add to dashboard Cite

The feedbacks from population density to demographic parameters, which drive population regulation, are the accumulated results of several ecological processes. The compensatory feedback from increased population density to fertility includes at least two distinct factors, the effects of decreases in per capita food level and increases in the social density (the number of interacting individuals). Because these effects have been studied separately, their relative importance is unknown. It is also unclear whether food limitation and social density combine additively to influence fertility. We investigated these questions with two factorial experiments on reproduction in the Least Killifish, Heterandria formosa. In one experiment, we crossed two levels of density with two levels of a total food ration that was distributed to all individuals. In the other experiment, we crossed two levels of density with two levels of per capita food. Whereas the first experiment suggested that the effects of variation in food level and density were synergistic, the second experiment indicated that they were not. The apparent synergism—the statistical interaction of food and density levels—was the result of confounding per capita food with social density in that design. In the second experiment, the effects of social density on reproductive rate were stronger than the effects of food level, whereas the effects of food level were stronger on offspring size at parturition than those of social density. The results suggest that the social stresses that emerge at higher densities play an important role in the compensatory response of fertility to density, a role, that is, at least as important as that of decreased per capita food levels.

show abstract

Section: Discussionmentioning

confidence: 88%

The effects of food level and social density on reproduction in the Least Killifish, Heterandria formosa

Leatherbury

Travis

2018

Ecology and Evolution

Self Cite

View full text Add to dashboard Cite

show abstract

“…Changes in these traits after maturity combined with differences in male survival among populations could account for differences in morphology among populations. TP males experience a higher rate of predation than males in WR (Landy & Travis, ; MacRae & Travis, ). However, the presence of an asymptote in the change of size and shape after maturity suggests that postmaturation changes in body shape and size do stop and at this point population differences persist.…”

Section: Discussionmentioning

confidence: 99%

“…The design of this experiment included fish from two populations, Trout pond (TP) and Wacissa river (WR). TP is a lentic pond with soft acidic water (pH 4.8–5.3; conductivity between 15–22 μMHOS and alkalinity around 10 mg/L) and harbors a population with consistently low conspecific density (Leips & Travis, ; MacRae & Travis, ; J. Travis, unpublished data). WR represents a distinctly different habitat.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Unique maternal and environmental effects on the body morphology of the Least Killifish, Heterandria formosa

Landy

Travis

2018

Ecology and Evolution

Self Cite

View full text Add to dashboard Cite

An important step in diagnosing local adaptation is the demonstration that phenotypic variation among populations is at least in part genetically based. To do this, many methods experimentally minimize the environmental effect on the phenotype to elucidate the genetic effect. Minimizing the environmental effect often includes reducing possible environmental maternal effects. However, maternal effects can be an important factor in patterns of local adaptation as well as adaptive plasticity. Here, we report the results of an experiment with males from two populations of the poeciliid fish, Heterandria formosa, designed to examine the relative influence of environmental maternal effects and environmental effects experienced during growth and development on body morphology, and, in addition, whether the balance among those effects is unique to each population. We used a factorial design that varied thermal environment and water chemistry experienced by mothers and thermal environment and water chemistry experienced by offspring. We found substantial differences between the two populations in their maternal and offspring norms of reaction of male body morphology to differences in thermal environment and water chemistry. We also found that the balance between maternal effects and postparturition environmental effects differed from one thermal regime to another and among traits. These results indicate that environmental maternal effects can be decidedly population‐specific and, as a result, might either contribute to the appearance of or blur evidence for local adaptation. These results also suggest that local adaptation might also occur through the evolution of maternal norms of reaction to important, and varying, environmental factors.

show abstract

“…We also collected H. formosa's most effective natural predator (Richardson et al, ), the sight‐feeding warmouth sunfish ( Lepomis gulosus ; n = 8) with bait traps at our population sites. Predator attack rates and densities have been estimated for warmouth at each of the locations (Macrae & Travis, ; Schrader et al, ). Predators were kept in individual tanks and away from all H. formosa but were fed H. formosa every other day.…”

Section: Experimental Designmentioning

confidence: 99%

Under pressure: Short‐ and long‐term response to predation varies in two populations of a live‐bearing fish

2019

Self Cite

View full text Add to dashboard Cite

The non‐lethal effects of predation can significantly influence animal behavior and population composition. Research has often centered around prey response to predator exposure in the short term, but fewer studies have highlighted the effects of long‐term predator exposures. In addition, studies of responses to predation risk are not always calibrated against the ecological history of predation risk in specific populations. We address these gaps by examining the effects of both long‐ and short‐term predator exposure on the behavior of individuals from populations that have different ecological histories of predation risk. We exposed individuals from high‐predation and low‐predation populations of the live‐bearing freshwater poeciliid, Heterandria formosa, to predators to assess changes in male reproductive behavior toward females. We also assessed longer‐term reproductive responses by exposing male and female H. formosa to predators at a random time of day, every day, for 30 days. In the presence of a predator, in the short term, males changed the frequency of their behaviors and females varied in their concentration of cortisol, demonstrating immediate responses to the perceived risk. The magnitude of these changes was larger in the population without a long history of predator exposure. However, we found that males and females did not change their reproductive output when exposed to predators over longer periods of time, suggesting that individuals acclimatize to the level of predation risk they experience. These results also suggest that short‐term variation in behavior or stress hormone responses should not be used as proxies for long‐term responses or fitness effects. Future work should assess both short‐term behavior and long‐term responses while simultaneously considering the ecological history of populations.

show abstract

The contribution of abiotic and biotic factors to spatial and temporal variation in population density of the least killifish, Heterandria formosa

Cited by 13 publications

References 30 publications

The effects of food level and social density on reproduction in the Least Killifish, Heterandria formosa

The effects of food level and social density on reproduction in the Least Killifish, Heterandria formosa

Unique maternal and environmental effects on the body morphology of the Least Killifish, Heterandria formosa

Under pressure: Short‐ and long‐term response to predation varies in two populations of a live‐bearing fish

Contact Info

Product

Resources

About