Offspring Size Variation in Eastern Mosquitofish (Gambusia holbrooki: Poeciliidae) from Contrasting Thermal Environments

Copeia ◽  
1990 ◽  
Vol 1990 (1) ◽  
pp. 10 ◽  
Author(s):  
Gary K. Meffe

Copeia ◽  
1997 ◽  
Vol 1997 (4) ◽  
pp. 869 ◽  
Author(s):  
Stephen C. Weeks ◽  
Gary K. Meffe


2019 ◽  
Author(s):  
Gretchen F. Wagner ◽  
Emeline Mourocq ◽  
Michael Griesser

Predation of offspring is the main cause of reproductive failure in many species, and the mere fear of offspring predation shapes reproductive strategies. Yet, natural predation risk is ubiquitously variable and can be unpredictable. Consequently, the perceived prospect of predation early in a reproductive cycle may not reflect the actual risk to ensuing offspring. An increased variance in investment across offspring has been linked to breeding in unpredictable environments in several taxa, but has so far been overlooked as a maternal response to temporal variation in predation risk. Here, we experimentally increased the perceived risk of nest predation prior to egg-laying in seven bird species. Species with prolonged parent-offspring associations increased their intra-brood variation in egg, and subsequently offspring, size. High risk to offspring early in a reproductive cycle can favour a risk-spreading strategy particularly in species with the greatest opportunity to even out offspring quality after fledging.



2021 ◽  
Vol 104 (2) ◽  
pp. 143-154
Author(s):  
Thomas J. Callaghan ◽  
Craig R. White ◽  
Mischa P. Turschwell


1991 ◽  
Vol 48 (1) ◽  
pp. 60-66 ◽  
Author(s):  
Gary K. Meffe

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.



1993 ◽  
Vol 50 (10) ◽  
pp. 2185-2191 ◽  
Author(s):  
Gary K. Meffe ◽  
Franklin F. Snelson Jr.

In animals, strategies of energy allocation among growth, maintenance and reproduction can be significantly altered by lipid storage. Poeciliid (livebearing) fishes store energy in late summer and fall for overwintering and first reproduction in spring, but details of energy use in reproduction are lacking. We conducted a laboratory experiment on the eastern mosquitofish (Gambusia holbrooki) and the sailfin molly (Poecilia latipinna) to document changes in lipid content in both the ovary and soma during development of a brood. In females of both species, ovarian lipid content was highest early in embryogeny and then declined; adult somatic lipids increased (were replenished) during embryonic development in mosquitofish, but declined in mollies. Larger clutches sequestered a larger share of body lipids in both species, possibly indicating energetic limits to reproduction. Finally, growth rate was positively correlated with somatic lipid content in both species, indicating among-individual differences in metabolic efficiency or feeding efficiency rather than a trade-off between growth and energy storage.



Limnetica ◽  
2011 ◽  
Vol 30 (1) ◽  
pp. 1-4
Author(s):  
Raquel Moreno-Valcárcel ◽  
Ana Ruiz-Navarro ◽  
Mar Torralva ◽  
Francisco José Oliva-Paterna


2012 ◽  
Vol 60 (4) ◽  
pp. 235 ◽  
Author(s):  
Kate D. L. Umbers ◽  
Michael D. Jennions ◽  
J. Scott Keogh

We isolated 25 new polymorphic microsatellite markers from the eastern mosquitofish, Gambusia holbrooki. Initially, 454 shotgun sequencing was used to identify 1187 loci for which primers could be designed. Of these 1187, we trialled 48 in the target species, 40 of which amplified a product of expected size. Subsequently, those 40 loci were screened for variation in 48 individuals from a single population in Canberra, Australia. Twenty loci were in Hardy–Weinberg equilibrium and polymorphic, with observed heterozygosity ranging from 0.04 to 0.72 (mean: 0.45 ± 0.18) and the number of alleles per locus ranged from 2 to 5 (mean: 3.20 ± 1.05). These loci will be useful in understanding genetic variation, paternity analysis and in managing this species across both its native and invasive range.





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