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Attila Hettyey - One of the best experts on this subject based on the ideXlab platform.
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Data for Chemical defence of Toad tadpoles under risk by four predator species
2019Co-Authors: Bálint Üveges, Herbert Hoi, Veronika Bókony, Ágnes M. Móricz, Márk Szederkényi, Katharina Mahr, Dániel Krüzselyi, Attila HettyeyAbstract:Data file for "Chemical defence of Toad tadpoles under risk by four predator species" (Ecology and Evolution, doi: 10.1002/ece3.5202). The data contains two worksheets, one dataset for the analysis of bufadienolide toxins of Common Toad (Bufo bufo) and one dataset for the predation trials.
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Resource-dependent temporal changes in antipredator behavior of Common Toad (Bufo bufo) tadpoles
Behavioral Ecology and Sociobiology, 2018Co-Authors: Anikó Kurali, Katalin Pásztor, Attila Hettyey, Zoltán TóthAbstract:Inducible behavioral defenses against predators, and how environmental factors mediate such responses, have been the focus of behavioral ecological research for decades. However, results often remained contradictory, perhaps because the ontogenetic context was ignored. Here, we investigated how antipredator behavioral responses of Common Toad ( Bufo bufo ) tadpoles are affected by food limitation and how the mediated responses changed during larval development. We raised tadpoles in the presence or absence of chemical cues indicating predation risk, combined with low or high food levels, and repeatedly monitored tadpole activity and visibility. We found that the presence of cues indicating predation risk and resource availability interactively affected visibility, but not relative activity, and this interactive effect changed with time over the larval period. Visibility of tadpoles decreased with time but to a greater extent when tadpoles were exposed to cues indicating predation risk compared to control groups, and this difference was more expressed when food was limited. Activity of tadpoles also decreased during larval development but to a greater extent in case of tadpoles raised in resource-limited environment compared to the other treatments. Also, activity of tadpoles was higher when food was scarce; however, the magnitude of this effect was not influenced by the predator-cue treatment. Thus, in addition to describing the trajectories of ontogenetic changes in tadpole behavior, our study also demonstrated that responses to environmental factors, such as predation threat and food availability, vary with age. Significance statement Antipredator behavior is a Common phenomenon in nature, and its expression is known to be influenced by the amount of available resources. How such defensive responses change with age, however, has been studied barely. By repeatedly observing Common Toad ( Bufo bufo ) tadpoles exposed to predators and/or food limitation, we found that tadpoles’ activity and visibility decreased with age and did so to a greater extent when tadpoles were exposed to chemical cues indicating predation risk compared to control groups. Our study demonstrated how responses to environmental factors, such as predation threat and food availability, vary with age in an important amphibian model species. These results draw attention to the importance of considering age when studying behavioral responses to environmental change and provide a possible explanation for some inconsistencies in the relevant literature.
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Resource-dependent temporal changes in antipredator behavior of Common Toad ( Bufo bufo ) tadpoles
Behavioral Ecology and Sociobiology, 2018Co-Authors: Anikó Kurali, Katalin Pásztor, Attila Hettyey, Zoltán TóthAbstract:Inducible behavioral defenses against predators, and how environmental factors mediate such responses, have been the focus of behavioral ecological research for decades. However, results often remained contradictory, perhaps because the ontogenetic context was ignored. Here, we investigated how antipredator behavioral responses of Common Toad (Bufo bufo) tadpoles are affected by food limitation and how the mediated responses changed during larval development. We raised tadpoles in the presence or absence of chemical cues indicating predation risk, combined with low or high food levels, and repeatedly monitored tadpole activity and visibility. We found that the presence of cues indicating predation risk and resource availability interactively affected visibility, but not relative activity, and this interactive effect changed with time over the larval period. Visibility of tadpoles decreased with time but to a greater extent when tadpoles were exposed to cues indicating predation risk compared to control groups, and this difference was more expressed when food was limited. Activity of tadpoles also decreased during larval development but to a greater extent in case of tadpoles raised in resource-limited environment compared to the other treatments. Also, activity of tadpoles was higher when food was scarce; however, the magnitude of this effect was not influenced by the predator-cue treatment. Thus, in addition to describing the trajectories of ontogenetic changes in tadpole behavior, our study also demonstrated that responses to environmental factors, such as predation threat and food availability, vary with age. Antipredator behavior is a Common phenomenon in nature, and its expression is known to be influenced by the amount of available resources. How such defensive responses change with age, however, has been studied barely. By repeatedly observing Common Toad (Bufo bufo) tadpoles exposed to predators and/or food limitation, we found that tadpoles’ activity and visibility decreased with age and did so to a greater extent when tadpoles were exposed to chemical cues indicating predation risk compared to control groups. Our study demonstrated how responses to environmental factors, such as predation threat and food availability, vary with age in an important amphibian model species. These results draw attention to the importance of considering age when studying behavioral responses to environmental change and provide a possible explanation for some inconsistencies in the relevant literature.
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age dependent changes in sensitivity to a pesticide in tadpoles of the Common Toad bufo bufo
Aquatic Toxicology, 2017Co-Authors: Zsanett Miko, Janos Ujszegi, Attila HettyeyAbstract:The worldwide en masse application of pesticides and the frequently reported malign effects on several non-target organisms underpin the importance of ecotoxicological research on these anthropogenic pollutants. Previous studies showed that sensitivity to herbicides can vary widely depending on additional stress factors, on the species and even on the population investigated. However, there is little information about how sensitivity changes during ontogeny, and how the duration of exposure is linked to the magnitude of malign effects, even though this knowledge would be important for the interpretation of toxicity test results and for formulating recommendations regarding the timing of pesticide application. We exposed tadpoles of the Common Toad (Bufo bufo) to three concentrations (0, 2 and 4mg a.e./L) of a glyphosate-based herbicide during the 1st, 2nd, 3rd, 4th, or 5th period of larval development or during the entire experiment, and measured survival, time until metamorphosis and body mass at metamorphosis to estimate fitness-consequences. Younger tadpoles were more sensitive to the herbicide in all measured traits than older ones, and this age-dependence was especially pronounced at the high herbicide concentration. Furthermore, tadpoles exposed to the herbicide during the entire experiment developed slower than tadpoles exposed only early on, but we did not observe a similar effect either on body mass or survival. The observed age-dependence of sensitivity to herbicides draws attention to the fact that results of toxicity tests obtained for one age-class are not necessarily generalizable across ontogeny. Also, the age of test animals has to be considered when planning ecotoxicological studies and interpreting their results. Finally, taking into account the temporal breeding habits of local amphibians when planning pesticide application would be highly favourable: if tadpoles would not get exposed to the herbicide during their most sensitive early development, they would sustain less anthropogenic damage from our efforts of controlling weeds.
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allocation in reproduction is not tailored to the probable number of matings in Common Toad bufo bufo males
Behavioral Ecology and Sociobiology, 2012Co-Authors: Attila Hettyey, Balazs Vagi, Janos Torok, Herbert HoiAbstract:The theory of life history evolution assumes trade-offs between competing fitness traits such as reproduction, somatic growth, and maintenance. One prediction of this theory is that if large individuals have a higher reproductive success, small/young individuals should invest less in reproduction and allocate more resources in growth than large/old individuals. We tested this prediction using the Common Toad (Bufo bufo), a species where mating success of males is positively related to their body size. We measured testes mass, soma mass, and sperm stock size in males of varying sizes that were either (1) re-hibernated at the start of the breeding season, (2) kept without females throughout the breeding season, or (3) repeatedly provided with gravid females. In the latter group, we also estimated fertilization success and readiness to re-mate. Contrary to our predictions, the relationship between testes mass and soma mass was isometric, sperm stock size relative to testes mass was unrelated to male size, fertilization success was not higher in matings with larger males, and smaller males were not less likely to engage in repeated matings than larger males. These results consistently suggest that smaller males did not invest less in reproduction to be able to allocate more in growth than larger males. Causes for this unexpected result may include relatively low year-to-year survival, unpredictable between-year variation in the strength of sexual selection and low return rates of lowered reproductive investment.
Zoltán Tóth - One of the best experts on this subject based on the ideXlab platform.
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Resource-dependent temporal changes in antipredator behavior of Common Toad (Bufo bufo) tadpoles
Behavioral Ecology and Sociobiology, 2018Co-Authors: Anikó Kurali, Katalin Pásztor, Attila Hettyey, Zoltán TóthAbstract:Inducible behavioral defenses against predators, and how environmental factors mediate such responses, have been the focus of behavioral ecological research for decades. However, results often remained contradictory, perhaps because the ontogenetic context was ignored. Here, we investigated how antipredator behavioral responses of Common Toad ( Bufo bufo ) tadpoles are affected by food limitation and how the mediated responses changed during larval development. We raised tadpoles in the presence or absence of chemical cues indicating predation risk, combined with low or high food levels, and repeatedly monitored tadpole activity and visibility. We found that the presence of cues indicating predation risk and resource availability interactively affected visibility, but not relative activity, and this interactive effect changed with time over the larval period. Visibility of tadpoles decreased with time but to a greater extent when tadpoles were exposed to cues indicating predation risk compared to control groups, and this difference was more expressed when food was limited. Activity of tadpoles also decreased during larval development but to a greater extent in case of tadpoles raised in resource-limited environment compared to the other treatments. Also, activity of tadpoles was higher when food was scarce; however, the magnitude of this effect was not influenced by the predator-cue treatment. Thus, in addition to describing the trajectories of ontogenetic changes in tadpole behavior, our study also demonstrated that responses to environmental factors, such as predation threat and food availability, vary with age. Significance statement Antipredator behavior is a Common phenomenon in nature, and its expression is known to be influenced by the amount of available resources. How such defensive responses change with age, however, has been studied barely. By repeatedly observing Common Toad ( Bufo bufo ) tadpoles exposed to predators and/or food limitation, we found that tadpoles’ activity and visibility decreased with age and did so to a greater extent when tadpoles were exposed to chemical cues indicating predation risk compared to control groups. Our study demonstrated how responses to environmental factors, such as predation threat and food availability, vary with age in an important amphibian model species. These results draw attention to the importance of considering age when studying behavioral responses to environmental change and provide a possible explanation for some inconsistencies in the relevant literature.
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Resource-dependent temporal changes in antipredator behavior of Common Toad ( Bufo bufo ) tadpoles
Behavioral Ecology and Sociobiology, 2018Co-Authors: Anikó Kurali, Katalin Pásztor, Attila Hettyey, Zoltán TóthAbstract:Inducible behavioral defenses against predators, and how environmental factors mediate such responses, have been the focus of behavioral ecological research for decades. However, results often remained contradictory, perhaps because the ontogenetic context was ignored. Here, we investigated how antipredator behavioral responses of Common Toad (Bufo bufo) tadpoles are affected by food limitation and how the mediated responses changed during larval development. We raised tadpoles in the presence or absence of chemical cues indicating predation risk, combined with low or high food levels, and repeatedly monitored tadpole activity and visibility. We found that the presence of cues indicating predation risk and resource availability interactively affected visibility, but not relative activity, and this interactive effect changed with time over the larval period. Visibility of tadpoles decreased with time but to a greater extent when tadpoles were exposed to cues indicating predation risk compared to control groups, and this difference was more expressed when food was limited. Activity of tadpoles also decreased during larval development but to a greater extent in case of tadpoles raised in resource-limited environment compared to the other treatments. Also, activity of tadpoles was higher when food was scarce; however, the magnitude of this effect was not influenced by the predator-cue treatment. Thus, in addition to describing the trajectories of ontogenetic changes in tadpole behavior, our study also demonstrated that responses to environmental factors, such as predation threat and food availability, vary with age. Antipredator behavior is a Common phenomenon in nature, and its expression is known to be influenced by the amount of available resources. How such defensive responses change with age, however, has been studied barely. By repeatedly observing Common Toad (Bufo bufo) tadpoles exposed to predators and/or food limitation, we found that tadpoles’ activity and visibility decreased with age and did so to a greater extent when tadpoles were exposed to chemical cues indicating predation risk compared to control groups. Our study demonstrated how responses to environmental factors, such as predation threat and food availability, vary with age in an important amphibian model species. These results draw attention to the importance of considering age when studying behavioral responses to environmental change and provide a possible explanation for some inconsistencies in the relevant literature.
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Variation in Chemical Defense Among Natural Populations of Common Toad, Bufo bufo, Tadpoles: the Role of Environmental Factors
Journal of Chemical Ecology, 2016Co-Authors: Veronika Bókony, Anikó Kurali, Katalin Pásztor, Zoltán Tóth, Zsanett Miko, Janos Ujszegi, Ágnes M. Móricz, Zsófia Tóth, Márk Szederkényi, Bálint ÜvegesAbstract:Defensive toxins are widespread in nature, yet we know little about how various environmental factors shape the evolution of chemical defense, especially in vertebrates. In this study we investigated the natural variation in the amount and composition of bufadienolide toxins, and the relative importance of ecological factors in predicting that variation, in larvae of the Common Toad, Bufo bufo , an amphibian that produces toxins de novo . We found that tadpoles’ toxin content varied markedly among populations, and the number of compounds per tadpole also differed between two geographical regions. The most consistent predictor of toxicity was the strength of competition, indicating that tadpoles produced more compounds and larger amounts of toxins when coexisting with more competitors. Additionally, tadpoles tended to contain larger concentrations of bufadienolides in ponds that were less prone to desiccation, suggesting that the costs of toxin production can only be afforded by tadpoles that do not need to drastically speed up their development. Interestingly, this trade-off was not alleviated by higher food abundance, as periphyton biomass had negligible effect on chemical defense. Even more surprisingly, we found no evidence that higher predation risk enhances chemical defenses, suggesting that low predictability of predation risk and high mortality cost of low toxicity might select for constitutive expression of chemical defense irrespective of the actual level of predation risk. Our findings highlight that the variation in chemical defense may be influenced by environmental heterogeneity in both the need for, and constraints on, toxicity as predicted by optimal defense theory.
C. J. Reading - One of the best experts on this subject based on the ideXlab platform.
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Male breeding behaviour and mate acquisition in the Common Toad, Bufo bufo
Journal of Zoology, 2009Co-Authors: C. J. Reading, R. T. ClarkeAbstract:The breeding behaviour ofa Common Toad (Bufo bufo) population was studied at a breeding pond on Portland, Dorset. Major Toad movements towards the breeding pond occurred on warm, wet nights when the temperature did not fall below 6°C. Males arrived earlier than females resulting in an initially exaggerated sex ratio which then slowly reduced as the breeding season progressed. No size assortative pairing was found although large males were more successful at mating than small males. Although males demonstrated no ESS (evolutionary stable strategy) in searching for a female between sites within the pond evidence suggesting the existence of one between the pond and an undefined area surrounding it was found.
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Non‐random pairing with respect to past breeding experience in the Common Toad (Bufo bufo)
Journal of Zoology, 2006Co-Authors: C. J. ReadingAbstract:A 20-year study of a Common Toad Bufo bufo population in south Dorset, U.K. was carried out between 1980 and 1999. On average, c. 33% of all experienced males and females arriving each year did so during the first quarter of each breeding season with only 18% arriving during the last quarter. Conversely, a slightly higher proportion (27%) of all inexperienced (first-time breeders) males and females arrived during the last quarter season than during the first quarter (22%). In 18 of the 20 years, the proportion of inexperienced females found paired with inexperienced males was significantly higher than could be expected from the proportion of inexperienced males in the pond, suggesting that selective pairing was occurring. One potential effect of pairings between inexperienced male and female Toads, coupled with the sex difference in the age of attaining sexual maturity, might be a reduction in the incidence of sibling matings (inbreeding) in the Common Toad. This is particularly relevant in a species that is both highly philopatric and which congregates in large numbers every spring to breed in very localized areas.
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non random pairing with respect to past breeding experience in the Common Toad bufo bufo
Journal of Zoology, 2006Co-Authors: C. J. ReadingAbstract:A 20-year study of a Common Toad Bufo bufo population in south Dorset, U.K. was carried out between 1980 and 1999. On average, c. 33% of all experienced males and females arriving each year did so during the first quarter of each breeding season with only 18% arriving during the last quarter. Conversely, a slightly higher proportion (27%) of all inexperienced (first-time breeders) males and females arrived during the last quarter season than during the first quarter (22%). In 18 of the 20 years, the proportion of inexperienced females found paired with inexperienced males was significantly higher than could be expected from the proportion of inexperienced males in the pond, suggesting that selective pairing was occurring. One potential effect of pairings between inexperienced male and female Toads, coupled with the sex difference in the age of attaining sexual maturity, might be a reduction in the incidence of sibling matings (inbreeding) in the Common Toad. This is particularly relevant in a species that is both highly philopatric and which congregates in large numbers every spring to breed in very localized areas.
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The effect of winter temperatures on the timing of breeding activity in the Common Toad Bufo bufo.
Oecologia, 1998Co-Authors: C. J. ReadingAbstract:A 19-year study of a Common Toad population in south Dorset, UK, was carried out between 1980 and 1998. The daily arrival of sexually mature male and female Toads at a breeding pond was recorded each year. The timing of the main arrival of Toads at the breeding pond was highly correlated with the mean daily temperatures over the 40 days immediately preceding the main arrival. When the temperatures were higher than average, breeding occurred significantly earlier in the year than if they were either average or lower than average. During the study, the Toad breeding seasons were early (2–13 February) in 5 years (1989, 1990, 1993, 1995, 1998), late (16–23 March) in 2 years (1986, 1996) and average (25 February–8 March) during the remaining 12 years. Evidence was found suggesting that Common Toads have a daylength threshold of about 9 h, below which the migration to the breeding pond does not occur. Evidence was also found indicating that Common Toads in southern England have a threshold temperature for activity of about 6°C and that the onset of breeding activity is highly correlated with the number of days during the 40 days prior to the main arrival at the breeding pond that were at or above this temperature. Predicting the start of the main breeding migration to a pond in any year may be possible by comparing the pattern of the 40-day running mean daily temperatures from 21 December the preceding year with those from previous years when the start of breeding activity is known. Although all five of the earliest recorded Toad breeding years occurred during the last 10 years, and were associated with the occurrence of particularly mild winters, a significant trend towards earlier breeding in recent years compared with previous years was not found.
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Breeding pond fidelity in the Common Toad, Bufo bufo
Journal of Zoology, 1991Co-Authors: C. J. Reading, Jon Loman, Thomas MadsenAbstract:Two independent studies of adult Common Toad, Bufo bufo, movements between different spawning ponds/populations both within and between years were made in England and Sweden during the spring breeding periods of1987–1990. The results of the two studies were subsequently combined since they were found to be complementary. In addition, in England during 1984 and 1985, large numbers of ‘Toadlets’ were marked so that they could be identified if recaptured as breeding adults. The degree of relocation between ponds was negatively correlated to the distance between ponds. The proportion of both males and females that moved between ponds within a particular year was significantly less than the proportion relocating between years. In any year, between 79% and 96% of adults that survived to breed the following year, returned to the original pond. Similarly, of the Toadlets marked during1984–85, 81% of the males that subsequently returned as breeding adults were captured in their pond of origin. Isolation, in relation to both population dynamics and population genetics, is defined and its implications for the management of Common Toad populatins discussed.
Anikó Kurali - One of the best experts on this subject based on the ideXlab platform.
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Resource-dependent temporal changes in antipredator behavior of Common Toad (Bufo bufo) tadpoles
Behavioral Ecology and Sociobiology, 2018Co-Authors: Anikó Kurali, Katalin Pásztor, Attila Hettyey, Zoltán TóthAbstract:Inducible behavioral defenses against predators, and how environmental factors mediate such responses, have been the focus of behavioral ecological research for decades. However, results often remained contradictory, perhaps because the ontogenetic context was ignored. Here, we investigated how antipredator behavioral responses of Common Toad ( Bufo bufo ) tadpoles are affected by food limitation and how the mediated responses changed during larval development. We raised tadpoles in the presence or absence of chemical cues indicating predation risk, combined with low or high food levels, and repeatedly monitored tadpole activity and visibility. We found that the presence of cues indicating predation risk and resource availability interactively affected visibility, but not relative activity, and this interactive effect changed with time over the larval period. Visibility of tadpoles decreased with time but to a greater extent when tadpoles were exposed to cues indicating predation risk compared to control groups, and this difference was more expressed when food was limited. Activity of tadpoles also decreased during larval development but to a greater extent in case of tadpoles raised in resource-limited environment compared to the other treatments. Also, activity of tadpoles was higher when food was scarce; however, the magnitude of this effect was not influenced by the predator-cue treatment. Thus, in addition to describing the trajectories of ontogenetic changes in tadpole behavior, our study also demonstrated that responses to environmental factors, such as predation threat and food availability, vary with age. Significance statement Antipredator behavior is a Common phenomenon in nature, and its expression is known to be influenced by the amount of available resources. How such defensive responses change with age, however, has been studied barely. By repeatedly observing Common Toad ( Bufo bufo ) tadpoles exposed to predators and/or food limitation, we found that tadpoles’ activity and visibility decreased with age and did so to a greater extent when tadpoles were exposed to chemical cues indicating predation risk compared to control groups. Our study demonstrated how responses to environmental factors, such as predation threat and food availability, vary with age in an important amphibian model species. These results draw attention to the importance of considering age when studying behavioral responses to environmental change and provide a possible explanation for some inconsistencies in the relevant literature.
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Resource-dependent temporal changes in antipredator behavior of Common Toad ( Bufo bufo ) tadpoles
Behavioral Ecology and Sociobiology, 2018Co-Authors: Anikó Kurali, Katalin Pásztor, Attila Hettyey, Zoltán TóthAbstract:Inducible behavioral defenses against predators, and how environmental factors mediate such responses, have been the focus of behavioral ecological research for decades. However, results often remained contradictory, perhaps because the ontogenetic context was ignored. Here, we investigated how antipredator behavioral responses of Common Toad (Bufo bufo) tadpoles are affected by food limitation and how the mediated responses changed during larval development. We raised tadpoles in the presence or absence of chemical cues indicating predation risk, combined with low or high food levels, and repeatedly monitored tadpole activity and visibility. We found that the presence of cues indicating predation risk and resource availability interactively affected visibility, but not relative activity, and this interactive effect changed with time over the larval period. Visibility of tadpoles decreased with time but to a greater extent when tadpoles were exposed to cues indicating predation risk compared to control groups, and this difference was more expressed when food was limited. Activity of tadpoles also decreased during larval development but to a greater extent in case of tadpoles raised in resource-limited environment compared to the other treatments. Also, activity of tadpoles was higher when food was scarce; however, the magnitude of this effect was not influenced by the predator-cue treatment. Thus, in addition to describing the trajectories of ontogenetic changes in tadpole behavior, our study also demonstrated that responses to environmental factors, such as predation threat and food availability, vary with age. Antipredator behavior is a Common phenomenon in nature, and its expression is known to be influenced by the amount of available resources. How such defensive responses change with age, however, has been studied barely. By repeatedly observing Common Toad (Bufo bufo) tadpoles exposed to predators and/or food limitation, we found that tadpoles’ activity and visibility decreased with age and did so to a greater extent when tadpoles were exposed to chemical cues indicating predation risk compared to control groups. Our study demonstrated how responses to environmental factors, such as predation threat and food availability, vary with age in an important amphibian model species. These results draw attention to the importance of considering age when studying behavioral responses to environmental change and provide a possible explanation for some inconsistencies in the relevant literature.
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Variation in Chemical Defense Among Natural Populations of Common Toad, Bufo bufo, Tadpoles: the Role of Environmental Factors
Journal of Chemical Ecology, 2016Co-Authors: Veronika Bókony, Anikó Kurali, Katalin Pásztor, Zoltán Tóth, Zsanett Miko, Janos Ujszegi, Ágnes M. Móricz, Zsófia Tóth, Márk Szederkényi, Bálint ÜvegesAbstract:Defensive toxins are widespread in nature, yet we know little about how various environmental factors shape the evolution of chemical defense, especially in vertebrates. In this study we investigated the natural variation in the amount and composition of bufadienolide toxins, and the relative importance of ecological factors in predicting that variation, in larvae of the Common Toad, Bufo bufo , an amphibian that produces toxins de novo . We found that tadpoles’ toxin content varied markedly among populations, and the number of compounds per tadpole also differed between two geographical regions. The most consistent predictor of toxicity was the strength of competition, indicating that tadpoles produced more compounds and larger amounts of toxins when coexisting with more competitors. Additionally, tadpoles tended to contain larger concentrations of bufadienolides in ponds that were less prone to desiccation, suggesting that the costs of toxin production can only be afforded by tadpoles that do not need to drastically speed up their development. Interestingly, this trade-off was not alleviated by higher food abundance, as periphyton biomass had negligible effect on chemical defense. Even more surprisingly, we found no evidence that higher predation risk enhances chemical defenses, suggesting that low predictability of predation risk and high mortality cost of low toxicity might select for constitutive expression of chemical defense irrespective of the actual level of predation risk. Our findings highlight that the variation in chemical defense may be influenced by environmental heterogeneity in both the need for, and constraints on, toxicity as predicted by optimal defense theory.
Rafael C. Lajmanovich - One of the best experts on this subject based on the ideXlab platform.
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Blood biomarkers of Common Toad Rhinella arenarum following chlorpyrifos dermal exposure.
Interdisciplinary toxicology, 2018Co-Authors: Rafael C. Lajmanovich, Paola M. Peltzer, Andrés M. Attademo, Carlina Leila Colussi, Candela Soledad MartinuzziAbstract:Chlorpyrifos (CPF) is a broad spectrum pesticide Commonly used for insect control, has great affinity for lipids and is thus a potential for bioaccumulation in aquatic organisms. The aim of this study was to evaluate the toxicity of CPF using the Common Toad Rhinella arenarum via dermal uptake in plastic bucket to simulate their natural exposition in ponds. R. arenarum Toads were exposed individually to solutions containing a nominal concentration of a commercial formulation of CPF insecticide (5 and 10 mg/L). Different enzyme biomarkers (BChE: butyrylcholinesterase, CbE: carboxylesterase, and CAT: catalase) were measured in blood tissue after exposition. The capacity of pyridine-2-aldoxime methochloride (2-PAM) to reverse OP-inhibited plasma BChE and the ratio of heterophils and lymphocytes (H/L) as hematological indicators of stress were also determined. The normal values of plasma B-sterases (BChE and CbE) were highly inhibited (until ≈ 70%) in Toads 48 h after exposure to CPF. The results indicate that 2-PAM produced BChE reactivation as well. The activity of CAT was also inducted for dermal exposure at more than double of that in the control Toads (CPF; 5 mg/L). H/L ratios did not reveal a significantly increased stress. The study suggests that CPF via dermal uptake induced neurotoxicity and oxidative stress in the Common Toad R. areanum. Thus, some blood biomarkers employed in our study (i.e. BChE, CbE, 2-PAM, and CAT) might be used as predictors in health and ecological risk assessment of amphibian populations exposed to CPF.
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Impact assessment of agriculture and livestock over age, longevity and growth of populations of Common Toad Rhinella arenarum (anura: Bufonidae), central area of Argentina
Global Ecology and Conservation, 2018Co-Authors: Clarisa De Lourdes Bionda, Selene Babini, Adolfo Ludovico Martino, Nancy Edith Salas, Rafael C. LajmanovichAbstract:Abstract The central area of Argentina has been greatly affected mainly due to urbanization and intensive agriculture (corn, soybean and cattle). Age, longevity and growth were determined in populations of the Common Toad, Rhinella arenarum, from urban and agricultural sites in the central area of Argentina. Five sites in Rio Cuarto (33o05′52.95″ S - 64o26′02.99″ W, 471 m a.s.l.; Cordoba Province, Argentina) with different degree of anthropic disturbance were selected to evaluate the impact of urbanization and agriculture on Common Toad populations as sentinel species. The selected sites were chosen according to intensive to moderate agricultural and livestock activity, low influence of agricultural and an intensive to moderate urban influence. A total of 114 adults (males and females) were sampled. Skeletochronology was used to estimate Toad's growth and age, which relies on the analysis of the annual Lines of Arrested Growth or LAGs in bones. Size, age and growth reductions occurrence in intensive agricultural systems could suggest long term impacts on fitness. In addition, intensive urban activity also affects life history of the population of R. arenarum, although to a lesser extent than the agricultural-livestock activity.
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Impact assessment of agriculture and livestock over age, longevity and growth of populations of Common Toad Rhinella arenarum (anura: Bufonidae), central area of Argentina
Elsevier, 2018Co-Authors: Clarisa De L. Bionda, Adolfo Ludovico Martino, Selene Babini, Nancy Edith Salas, Rafael C. LajmanovichAbstract:The central area of Argentina has been greatly affected mainly due to urbanization and intensive agriculture (corn, soybean and cattle). Age, longevity and growth were determined in populations of the Common Toad, Rhinella arenarum, from urban and agricultural sites in the central area of Argentina. Five sites in Rio Cuarto (33º05′52.95″ S - 64º26′02.99″ W, 471 m a.s.l.; Córdoba Province, Argentina) with different degree of anthropic disturbance were selected to evaluate the impact of urbanization and agriculture on Common Toad populations as sentinel species. The selected sites were chosen according to intensive to moderate agricultural and livestock activity, low influence of agricultural and an intensive to moderate urban influence. A total of 114 adults (males and females) were sampled. Skeletochronology was used to estimate Toad's growth and age, which relies on the analysis of the annual Lines of Arrested Growth or LAGs in bones. Size, age and growth reductions occurrence in intensive agricultural systems could suggest long term impacts on fitness. In addition, intensive urban activity also affects life history of the population of R. arenarum, although to a lesser extent than the agricultural-livestock activity. Keywords: Rhinella arenarum Toad, Agriculture, Urbanization, Skeletochronology, Age, von Bertalanffy mode
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harmful effects of the dermal intake of commercial formulations containing chlorpyrifos 2 4 d and glyphosate on the Common Toad rhinella arenarum anura bufonidae
Water Air and Soil Pollution, 2015Co-Authors: Rafael C. Lajmanovich, Paola M. Peltzer, Andrés M. Attademo, Celina Maria Junges, Maria Fernanda Simoniello, Gisela Laura Poletta, Paula Grenon, Mariana C CabagnazenklusenAbstract:Amphibians have complex life cycles with aquatic and terrestrial life and uncovered skins; therefore, they are exposed to chemical contamination, where dermal exposure is a significant route for pesticide uptake in both habitats. In this study, measurements in blood samples such as levels of butyrylcholinesterase (BChE), carboxylesterase (CbE), glutathione S-transferases (GST), thiobarbituric acid reactive substances (TBARS), modified alkaline comet assay (ACA) for detection of oxidized bases (FPG and Endo III sites), as well as the ratio of heterophils and lymphocytes (H/L), were evaluated as non-destructive biomarkers to monitor dermal pesticide exposure in male Toads of Rhinella arenarum. Toads were exposed to a solution containing a nominal concentration of commercial formulations of the insecticide chlorpyrifos (CPF, 10 mg/L), and herbicides 2,4-D and glyphosate (GLY) (20 mg/L, respectively). After 48 h of exposure, the levels of plasma B-sterases (BChE and CbE) were inhibited (55 and 43 %, respectively) in Toads exposed to CPF. Also, the activity of GST was inducted for dermal exposure to 2,4-D, as well as the levels of TBARS due to CPF exposure. Besides this, CPF and 2,4-D exposure induced oxidative DNA damage, and the H/L ratio decreased for the both herbicide exposures. Our results showed that exposure via dermal uptake to CPF, 2,4-D, and GLY in the Common Toad R. arenarum induced neurotoxicity, oxidative stress, and immunological depression. Thus, some blood biomarkers employed in our study (B-esterases, GST, levels of TBARS, ACA, and H/L ratio) might be used as predictors in health and ecological risk assessment of amphibian populations exposed to OP insecticides and herbicides.
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Age structure, growth and longevity in the Common Toad, Rhinella arenarum, from Argentina
Acta Herpetologica, 2015Co-Authors: Clarisa De Lourdes Bionda, Rafael C. Lajmanovich, Nancy Edith Salas, Silvia Kost, Ulrich Sinsch, Adolfo Ludovico MartinoAbstract:Age structure, growth and longevity was determined in the Common Toad, Rhinella arenarum, from a sub - urban pond located in the Pampa plains, central Argentina during two breeding seasons, in 2000 and 2008 by using skeletochronology, which relies on the analysis of the annual lines of arrested growth (LAGs) in bones. Both females and males were captured in 2008, while only males were recorded in 2000. Females were significantly larger than males. Mean population age was 2.4 ± 0.9 years in 2000. In 2008, the difference in age was not significant between the sexes (Males: 3.0 ± 0.7, n = 21; Females: 2.6 ± 0.9, n = 12), neither between males in 2000 and 2008. The longev - ity in males of 2000 was 6 LAGs and exceeded that of males (5 LAGs) and females (4 LAGs) in 2008. Von Bertalanffy curves showed that the growth coefficient in the males of 2000 (K = 2.97 ± 0.47) was almost double that of females (K = 1.21 ± 0.10) and males (K = 1.01 ± 0.14) of 2008. Males and females Rhinella arenarum show different morpho - logical and life history traits and the year of sampling can significantly influence the estimation of the studied param -