Russian Journal of Herpetology Vol 10 No 2 2003, pp 87-92 HABITAT OCCUPANCY AND INFLUENCE OF ABIO... more Russian Journal of Herpetology Vol 10 No 2 2003, pp 87-92 HABITAT OCCUPANCY AND INFLUENCE OF ABIOTIC FACTORS ON THE OCCURRENCE OF Nyctibattachus major (BOULENGER) IN CENTRAL WESTERN GHATS, INDIA KV Gururaja,1 AH Manjunatha Reddy,1 1 1 J, ...
American toad tadpoles (Bufo americanus) were exposed to malathion and nitrate in a fully factori... more American toad tadpoles (Bufo americanus) were exposed to malathion and nitrate in a fully factorial experiment that crossed four concentrations of malathion ranging between 0 and 1,000 µg malathion/L, and five concentrations of nitrate ranging from 0 to 16 mg NO(3) -N/L to identify single and interactive effects. In this 21-d experiment, we recorded tadpole length, mass, survivorship, and frequencies of diamond-shaped and stiff-tail abnormalities. Malathion increased frequency of diamond-shaped and stiff-tail abnormalities, and negatively affected survivorship, but did not affect tadpole size. Nitrate did not affect survivorship but did have sublethal effects, including effects on tadpole length and the frequency of both abnormalities. The interaction of malathion and nitrate has no effect on survivorship or tadpole size but did affect the frequency of abnormalities, with nitrate reducing malathion's effect. Results of the present study suggest that at the environmentally realistic concentrations used in our experiment, malathion has both lethal and sublethal effects, but nitrate had only sublethal effects on American toad tadpoles. The combination of malathion and nitrate had limited effects at the tested concentrations under laboratory conditions. However, the effect of the combined treatments on the frequency of tadpole developmental abnormalities suggests that such interactions may play a role under field conditions, in which pesticide and nitrate fertilizers are typically applied simultaneously.
Use of pesticides and other agro-chemicals adversely influence amphibians either directly by kill... more Use of pesticides and other agro-chemicals adversely influence amphibians either directly by killing them or by inducing sublethal, chronic effects. Many studies have investigated the effect of mixtures of pesticides or fertilizers. We studied the combined effects of nitrate and malathion ([(dimethoxy phosphino thioyl] butanediotae) on the early growth, expression of abnormalities, and mortality of Wood Frog (Rana sylvatica) tadpoles in a laboratory experiment. Tadpoles were treated with factorial combinations of 0, 8, and 16 mg NO3–N l−1 and 0, 250, 500, and 1,000 μg malathion l−1 for a period of 14 days. Feeding behaviour, total length, mean tadpole mass, frequencies of abnormalities, and survivorship in each treatment were recorded. Malathion showed a significant negative influence on all parameters and strongly influenced the frequencies of morphological anomalies. In contrast, nitrate alone did not produce any significant effects on behavior, total length, tadpole mass, or the frequency of abnormalities during the experiment. Malathion and nitrate had an interactive effect on tadpole length and mass, but did not affect any other parameters. Our results suggest that exposure to malathion, even at relatively low concentrations can have serious negative consequences for Wood Frog tadpoles. In addition, our results also indicate that there was little synergistic interaction between malathion and nitrate exposure under laboratory conditions.
Journal of Environmental Science and Health Part B-pesticides Food Contaminants and Agricultural Wastes, 2012
This study was undertaken to determine the effect of environmentally realistic concentrations of ... more This study was undertaken to determine the effect of environmentally realistic concentrations of two commonly used pesticides viz., malathion and cypermethrin, using a fully 3 × 3 factorial experiments on the survivability and time of metamorphosis in a common rice paddy field frog (cricket frog) Fejervarya limnocharis under laboratory conditions. The results suggest that cypermethrin is more toxic than malathion and combinations of higher concentrations of cypermethrin (50 μg/L) with malathion (250 and 500 μg/L) are more deleterious to the survivability of tadpoles. With increasing cypermethrin concentration, the survivability of tadpole decreased (r = −0.986, P = 0.108). But cypermethrin alone induced early metamorphosis among the surviving tadpoles. However, there was a delay in the time required for metamorphosis induced by malathion and its combination with cypermethrin. The delay in metamorphosis may indicate the altered physiological fitness of the individual. The emergent froglets will be subjected to environmental stressors like high temperature and less humidity of post-monsoon tropical climate that could enhance negative influence triggered by pesticides.
Organisms living in aquatic ecosystems are increasingly likely to be exposed to multiple pollutan... more Organisms living in aquatic ecosystems are increasingly likely to be exposed to multiple pollutants at the same time due to the simultaneous use of several pesticides and fertilizers. We examined the single and interactive effects of environmentally realistic concentrations of nitrate and malathion on two species of tadpoles common in agricultural regions of the United States—the American Toad (Bufo americanus) and the Wood Frog (Rana sylvatica)—using a fully factorial mesocosm experiment that crossed four concentrations of malathion ranging from 0 to 1000 μg/l and two concentrations of nitrate (0 or 8 mg/l). In both B. americanus and R. sylvatica, malathion delayed metamorphosis compared to controls, even at the lowest concentration of malathion. Malathion did not affect survivorship in either species. B. americanus metamorphs were smaller in malathion treatments, whereas R. sylvatica were larger in malathion treatments. Nitrate did not affect survivorship or metamorph size in either species, but did accelerate time to metamorphosis in R. sylvatica. The interaction between nitrate and malathion had no effects in B. americanus and had no effect on R. sylvatica survivorship or metamorph size. However, in the 250 μg/l and 500 μg/l malathion treatments, nitrate reduced the negative effect of malathion on time to metamorphosis in R. sylvatica such that there was little if any delay in metamorphosis compared to the controls in these treatment combinations. This observation suggests that the presence of nitrate might ameliorate the effects of malathion on R. sylvatica. Our results suggest that malathion could have significant effects on anuran populations and communities and that nitrate might potentially mediate such effects in some species.
Despite mounting concerns about amphibian population declines, information on impact of pesticide... more Despite mounting concerns about amphibian population declines, information on impact of pesticides on physiological changes is meager. The present study deals the influence of an organophosphate pesticide—malathion on the lipid metabolism of Limnonectus limnocharis under laboratory conditions. Changes in the lipid metabolism were analyzed in the liver, muscle, ovary, and testis of frogs exposed to lethal (10.67 mg L−1 for 1, 2, 3, and 4 days) and sub-lethal (2.13 mg L−1 for 1, 5, 10, 15, 20, and 25 days) concentrations of malathion. Upon lethal concentration treatment, against the increase of fatty acids, glycerol, and lipase activities in all tested tissues, there was decrease in the total lipids content over different durations. On the other hand, exposure to sub-lethal concentration, the amount of total lipids content, free fatty acids, glycerol and lipase activity increased. Changes in the lipid metabolism due to lethal concentration of malathion exposure could depict the negative impact on the reproductive success, which would result in decline of amphibian population.
Abstract. The present paper reports the abnormalities recorded among four species of frogs: Limno... more Abstract. The present paper reports the abnormalities recorded among four species of frogs: Limnonectus limnocharis, L. keralensis, L. brevipalmata, and Tomopterna (Spherotheca) rufescens inhabiting forest, water bodies, agriculture (paddy) fields and coffee plantations. The ...
The effects of short-term exposure (28 days) of free-feeding Limnonectus limnocharis (Indian cric... more The effects of short-term exposure (28 days) of free-feeding Limnonectus limnocharis (Indian cricket frog) tadpoles to field concentrations of malathion were investigated. This frog species is a major biotic component of the agroecosystems of the Western Ghats (13°18′, 75°25′ and 13°22′, 75°28′), where malathion (diethyl [(dimethoxy phosphino thioyl] butanediote), an organophosphate pesticide, is being used extensively. Although malathion is known to cause nonreversible acetylcholine inhibition and diminishes activity, growth and development in amphibian tadpoles, such data on Indian amphibian species are lacking. In the present study, increments in the following were used to assess such an impact: tadpole growth; increase in total length, body length, tail length, and body weight; and food consumption. The different concentrations of malathion employed were 500, 1000, 1500, 2000, and 3000 μg L–1. Malathion exposure produced significant effects on all measured parameters. Tadpole survival decreased from 20 to 6 tadpoles, with an increase in concentration followed by a decrease in growth. Food consumption of surviving tadpoles also decreased (0.067 mg.g–1.d–1 to 0.0075 mg.g–1.d–1) with increased malathion. Decreased food consumption, growth, and development of L. limnocharis tadpoles with an increase of malathion concentration (within field concentration range) over temporal scale reveal the possible threat to this species in the agroecosystems of the Western Ghats.
Russian Journal of Herpetology Vol 10 No 2 2003, pp 87-92 HABITAT OCCUPANCY AND INFLUENCE OF ABIO... more Russian Journal of Herpetology Vol 10 No 2 2003, pp 87-92 HABITAT OCCUPANCY AND INFLUENCE OF ABIOTIC FACTORS ON THE OCCURRENCE OF Nyctibattachus major (BOULENGER) IN CENTRAL WESTERN GHATS, INDIA KV Gururaja,1 AH Manjunatha Reddy,1 1 1 J, ...
American toad tadpoles (Bufo americanus) were exposed to malathion and nitrate in a fully factori... more American toad tadpoles (Bufo americanus) were exposed to malathion and nitrate in a fully factorial experiment that crossed four concentrations of malathion ranging between 0 and 1,000 µg malathion/L, and five concentrations of nitrate ranging from 0 to 16 mg NO(3) -N/L to identify single and interactive effects. In this 21-d experiment, we recorded tadpole length, mass, survivorship, and frequencies of diamond-shaped and stiff-tail abnormalities. Malathion increased frequency of diamond-shaped and stiff-tail abnormalities, and negatively affected survivorship, but did not affect tadpole size. Nitrate did not affect survivorship but did have sublethal effects, including effects on tadpole length and the frequency of both abnormalities. The interaction of malathion and nitrate has no effect on survivorship or tadpole size but did affect the frequency of abnormalities, with nitrate reducing malathion's effect. Results of the present study suggest that at the environmentally realistic concentrations used in our experiment, malathion has both lethal and sublethal effects, but nitrate had only sublethal effects on American toad tadpoles. The combination of malathion and nitrate had limited effects at the tested concentrations under laboratory conditions. However, the effect of the combined treatments on the frequency of tadpole developmental abnormalities suggests that such interactions may play a role under field conditions, in which pesticide and nitrate fertilizers are typically applied simultaneously.
Use of pesticides and other agro-chemicals adversely influence amphibians either directly by kill... more Use of pesticides and other agro-chemicals adversely influence amphibians either directly by killing them or by inducing sublethal, chronic effects. Many studies have investigated the effect of mixtures of pesticides or fertilizers. We studied the combined effects of nitrate and malathion ([(dimethoxy phosphino thioyl] butanediotae) on the early growth, expression of abnormalities, and mortality of Wood Frog (Rana sylvatica) tadpoles in a laboratory experiment. Tadpoles were treated with factorial combinations of 0, 8, and 16 mg NO3–N l−1 and 0, 250, 500, and 1,000 μg malathion l−1 for a period of 14 days. Feeding behaviour, total length, mean tadpole mass, frequencies of abnormalities, and survivorship in each treatment were recorded. Malathion showed a significant negative influence on all parameters and strongly influenced the frequencies of morphological anomalies. In contrast, nitrate alone did not produce any significant effects on behavior, total length, tadpole mass, or the frequency of abnormalities during the experiment. Malathion and nitrate had an interactive effect on tadpole length and mass, but did not affect any other parameters. Our results suggest that exposure to malathion, even at relatively low concentrations can have serious negative consequences for Wood Frog tadpoles. In addition, our results also indicate that there was little synergistic interaction between malathion and nitrate exposure under laboratory conditions.
Journal of Environmental Science and Health Part B-pesticides Food Contaminants and Agricultural Wastes, 2012
This study was undertaken to determine the effect of environmentally realistic concentrations of ... more This study was undertaken to determine the effect of environmentally realistic concentrations of two commonly used pesticides viz., malathion and cypermethrin, using a fully 3 × 3 factorial experiments on the survivability and time of metamorphosis in a common rice paddy field frog (cricket frog) Fejervarya limnocharis under laboratory conditions. The results suggest that cypermethrin is more toxic than malathion and combinations of higher concentrations of cypermethrin (50 μg/L) with malathion (250 and 500 μg/L) are more deleterious to the survivability of tadpoles. With increasing cypermethrin concentration, the survivability of tadpole decreased (r = −0.986, P = 0.108). But cypermethrin alone induced early metamorphosis among the surviving tadpoles. However, there was a delay in the time required for metamorphosis induced by malathion and its combination with cypermethrin. The delay in metamorphosis may indicate the altered physiological fitness of the individual. The emergent froglets will be subjected to environmental stressors like high temperature and less humidity of post-monsoon tropical climate that could enhance negative influence triggered by pesticides.
Organisms living in aquatic ecosystems are increasingly likely to be exposed to multiple pollutan... more Organisms living in aquatic ecosystems are increasingly likely to be exposed to multiple pollutants at the same time due to the simultaneous use of several pesticides and fertilizers. We examined the single and interactive effects of environmentally realistic concentrations of nitrate and malathion on two species of tadpoles common in agricultural regions of the United States—the American Toad (Bufo americanus) and the Wood Frog (Rana sylvatica)—using a fully factorial mesocosm experiment that crossed four concentrations of malathion ranging from 0 to 1000 μg/l and two concentrations of nitrate (0 or 8 mg/l). In both B. americanus and R. sylvatica, malathion delayed metamorphosis compared to controls, even at the lowest concentration of malathion. Malathion did not affect survivorship in either species. B. americanus metamorphs were smaller in malathion treatments, whereas R. sylvatica were larger in malathion treatments. Nitrate did not affect survivorship or metamorph size in either species, but did accelerate time to metamorphosis in R. sylvatica. The interaction between nitrate and malathion had no effects in B. americanus and had no effect on R. sylvatica survivorship or metamorph size. However, in the 250 μg/l and 500 μg/l malathion treatments, nitrate reduced the negative effect of malathion on time to metamorphosis in R. sylvatica such that there was little if any delay in metamorphosis compared to the controls in these treatment combinations. This observation suggests that the presence of nitrate might ameliorate the effects of malathion on R. sylvatica. Our results suggest that malathion could have significant effects on anuran populations and communities and that nitrate might potentially mediate such effects in some species.
Despite mounting concerns about amphibian population declines, information on impact of pesticide... more Despite mounting concerns about amphibian population declines, information on impact of pesticides on physiological changes is meager. The present study deals the influence of an organophosphate pesticide—malathion on the lipid metabolism of Limnonectus limnocharis under laboratory conditions. Changes in the lipid metabolism were analyzed in the liver, muscle, ovary, and testis of frogs exposed to lethal (10.67 mg L−1 for 1, 2, 3, and 4 days) and sub-lethal (2.13 mg L−1 for 1, 5, 10, 15, 20, and 25 days) concentrations of malathion. Upon lethal concentration treatment, against the increase of fatty acids, glycerol, and lipase activities in all tested tissues, there was decrease in the total lipids content over different durations. On the other hand, exposure to sub-lethal concentration, the amount of total lipids content, free fatty acids, glycerol and lipase activity increased. Changes in the lipid metabolism due to lethal concentration of malathion exposure could depict the negative impact on the reproductive success, which would result in decline of amphibian population.
Abstract. The present paper reports the abnormalities recorded among four species of frogs: Limno... more Abstract. The present paper reports the abnormalities recorded among four species of frogs: Limnonectus limnocharis, L. keralensis, L. brevipalmata, and Tomopterna (Spherotheca) rufescens inhabiting forest, water bodies, agriculture (paddy) fields and coffee plantations. The ...
The effects of short-term exposure (28 days) of free-feeding Limnonectus limnocharis (Indian cric... more The effects of short-term exposure (28 days) of free-feeding Limnonectus limnocharis (Indian cricket frog) tadpoles to field concentrations of malathion were investigated. This frog species is a major biotic component of the agroecosystems of the Western Ghats (13°18′, 75°25′ and 13°22′, 75°28′), where malathion (diethyl [(dimethoxy phosphino thioyl] butanediote), an organophosphate pesticide, is being used extensively. Although malathion is known to cause nonreversible acetylcholine inhibition and diminishes activity, growth and development in amphibian tadpoles, such data on Indian amphibian species are lacking. In the present study, increments in the following were used to assess such an impact: tadpole growth; increase in total length, body length, tail length, and body weight; and food consumption. The different concentrations of malathion employed were 500, 1000, 1500, 2000, and 3000 μg L–1. Malathion exposure produced significant effects on all measured parameters. Tadpole survival decreased from 20 to 6 tadpoles, with an increase in concentration followed by a decrease in growth. Food consumption of surviving tadpoles also decreased (0.067 mg.g–1.d–1 to 0.0075 mg.g–1.d–1) with increased malathion. Decreased food consumption, growth, and development of L. limnocharis tadpoles with an increase of malathion concentration (within field concentration range) over temporal scale reveal the possible threat to this species in the agroecosystems of the Western Ghats.
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