Differences in survival functions of mosquitofish (Gambusia affinis) and sand shiner (Notropis ludibundus) genotypes exposed to pesticides

Abstract

Differential genotypic tolerance of two species of fish native to the Great Plains of North America (the western mosquitofish [Gambusia affinis] and the sand shiner [Notropis ludibundus]) was examined in 96-h acute exposures to the pesticides lindane and parathion. Although a significant amount of data is available indicating that heavy metals cause selective genotypic mortality in aquatic organisms, very few studies have focused on the effects of pesticides on population genetic structure. Fish used in this experiment were captured from field populations in Kansas, USA, and acclimated to laboratory conditions for 1 month before the acute toxicity tests. Two hundred individuals of each species were exposed, in two separate experiments, to estimated LC70 concentrations of each pesticide for 96 h. Dead individuals were removed at 3-h intervals allowing for comparison of genotypic times-to-death. Individuals of each species were electrophoretically examined at two polymorphic loci. Phenotypes of mosquitofish were determined for phosphoglucose mutase (PGM ) and malic enzyme (ME ). Phenotypes of sand shiners were determined for PGM and aspartate aminotransferase (AAT ). Three of eight statistical tests (two species ϫ two loci ϫ two pesticides) indicated significant differences among survival curves of genotypic classes. Genotypes of ME and PGM of mosquitofish exhibited significantly different survivorship functions in the parathion and lindane time-to-death tests, respectively. Genotypes of AAT of sand shiners exhibited significantly different survivorship curves when exposed to lindane. Given certain experimental limitations, these results support a continued examination of population genetic characteristics as biomarkers of environmental contamination.

Responses of European flounder Platichthys flesus populations to contamination in different estuaries along the Atlantic coast of France

“…Modifications on the PGM locus have already been reported in populations experiencing chemical stress by heavy metals, HAP, PCB, pesticides etc. (Foré et al 1995, Hebert & Luiker 1996, Heithaus & Laushman 1997, Sullivan & Lydy 1999, Moraga & Tanguy 2000. Other authors described a 7 to 11% increase in a pollutant-tolerating allele of PGM in 2 heavily contaminated populations of a freshwater fish compared to a pristine population (Larno et al 2001), and confirmed this trend over the whole Rhône River basin.…”

EFFECT OF MERCURY AND Gpi-2 GENOTYPE ON STANDARD METABOLIC RATE OF EASTERN MOSQUITOFISH (GAMBUSIA HOLBROOKI)

“…Allozymes have been used as markers for the effects of pollutants on the genetic structure of natural and experimental populations [1][2][3][4][5][6][7][8]. Allozyme genotypes have also proved useful in predicting individual differences in susceptibility to toxicants in laboratory exposures [3,[9][10][11][12][13][14]. Although allozyme studies of exposed populations may be conducted without considering the mechanisms underlying the observed effects, understanding the mechanisms would greatly increase the value of allozyme studies.…”

“…Correlation between allozyme genotype frequencies and contaminant exposure in natural and experimental populations and differential susceptibility of specific allozyme genotypes during laboratory exposures to toxicants have provided evidence that variation in allozymes might be useful for detecting the effects of toxicants on natural populations [14][15][16]. The number of experiments investigating changes in allozyme frequencies in exposed populations and differential sensitivities of allozyme genotypes to toxicants continues to grow, but studies investigating mechanisms underlying the correlation between allozyme genotype and effects of toxicants are relatively uncommon.…”

Differential resistance to copper and mine drainage in Daphnia longispina: Relationship with allozyme genotypes

“…Other authors, however, found the opposite trend in populations of Pimephales promelas exposed to fluoranthene [41] and of the gastropod Pleurocera canaliculatum exposed to mercury [42]. These differences in genotype sensitivity were found after both acute [3,5,8,12,37] and chronic [2] laboratory exposure. Differences in the acute sensitivity of the genotypes, however, were not always related to their prevalence in chronically impacted populations [8].…”

“…Differential sensitivity of allozyme genotypes to pollutants, namely metals, have been reported in several different taxa, such as plants [1], fish [2][3][4], mollusks [5], crustaceans [6], and insects [7,8]. This differential sensitivity can ultimately result in alterations in the gene pool of the populations impacted by contaminants.…”