8 results on '"Valeria Isabel Gómez"'
Search Results
2. Effect of soil disturbance by agricultural activities on the life history traits of monkey frog (Pithecopus azureus)
- Author
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Arturo Ignacio Kehr and Valeria Isabel Gómez
- Subjects
010504 meteorology & atmospheric sciences ,media_common.quotation_subject ,Environment ,010501 environmental sciences ,Management, Monitoring, Policy and Law ,01 natural sciences ,Soil ,Animal science ,Animals ,Ecotoxicology ,Metamorphosis ,Life History Traits ,0105 earth and related environmental sciences ,General Environmental Science ,media_common ,Larva ,biology ,Metamorphosis, Biological ,Agriculture ,Soil classification ,General Medicine ,Hydrogen-Ion Concentration ,biology.organism_classification ,Pollution ,Tadpole ,Soil water ,Paddy field ,Anura ,Microcosm - Abstract
We assessed whether soil disturbance by agricultural activity influences the growth, development, and survival of individuals in the larval, metamorphic, and postmetamorphic stages of amphibians. Tadpoles of Pithecopus azureus (Cope, 1862) were reared in microcosms assembled with soil from two sites, a pristine site and a rice field. For 5 weeks, we recorded tadpole growth and development as well as physicochemical variable of the water: temperature, conductivity, dissolved oxygen, and pH. The results show that rice field soil produced a level of acidification in the water that influenced the growth and development rates of tadpoles. Tadpoles reared in rice soil had a significantly lower growth rate and body length, and during a specified period, the development rate of the tadpole was significantly lower than that of tadpoles in pristine soil. Overall, tadpoles in rice soil took 3 days longer to reach metamorphosis and 1 additional day to complete metamorphosis compared with tadpoles exposed to pristine soil. Our study shows that disturbed soils modify the physicochemical conditions of temporary ponds, impacting on the initial life stage of the anurans.
- Published
- 2019
- Full Text
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3. Morphological variation of aplectana hylambatis (Nematoda: Cosmocercidae) from different anuran hosts and localities in Argentina
- Author
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Monika Inés Hamann, Valeria Isabel Gómez, and Cynthya Elizabeth Gonzalez
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Male ,0106 biological sciences ,Nematoda ,COSMOCERCID NEMATODES ,Argentina ,Morphological variation ,Zoology ,AMPHIBIANS ,010603 evolutionary biology ,01 natural sciences ,Aplectana ,Intraspecific competition ,Host-Parasite Interactions ,030308 mycology & parasitology ,INTRASPECIFIC VARIABILITY ,purl.org/becyt/ford/1 [https] ,03 medical and health sciences ,Sponge spicule ,morphology ,Animals ,lcsh:Science ,purl.org/becyt/ford/1.6 [https] ,intraspecific variability ,0303 health sciences ,amphibians ,Multidisciplinary ,Geography ,biology ,Host (biology) ,Cosmocercidae ,cosmocercid nematodes ,biology.organism_classification ,Geographic distribution ,Nematode ,MORPHOLOGY ,lcsh:Q ,Female ,Anura - Abstract
Aplectana hylambatis is a nematode witha wide geographic distribution and low host specificity. In spite of numerousreports, until this moment, the morphological variations between differenthosts and localities have not been studied. We studied 401 specimens collectedfrom five host species from seven localities in Argentina, and examined thefollowing morphological characters: mamelon-like cuticular protuberancesanterior to the vulva, structure of the gubernaculum and the spicules, numberand arrangement of caudal papillae, and the measurements of twelve charactersin females and eleven characters in males. The results showed that mamelon-likeprotuberances and caudal papillae varied in number and arrangement between differenthosts and localities. The metrical study revealed that five characters in malesand six in females contributed to variability; nine characters showedsignificant differences between host species and localities. Specimens of A.hylambatis collected from R. arenarum formed a group clearly differentiatedfrom the rest of the specimens. The results from this study highlight theimportance of examining as many specimens as possible from different hostsamples and from several localities to cover the intraspecific variations. Fil: Gonzalez, Cynthya Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentina Fil: Gómez, Valeria Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentina Fil: Hamann, Mónika Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentina
- Published
- 2019
4. Habitat size changes morphological traits of Physalaemus albonotatus tadpoles
- Author
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Valeria Isabel Gómez and Arturo Ignacio Kehr
- Subjects
0106 biological sciences ,Phenotypic plasticity ,Physalaemus albonotatus ,WATER DEPTH ,Ecology ,010607 zoology ,Biology ,Ecología ,biology.organism_classification ,SURFACE AREA ,010603 evolutionary biology ,01 natural sciences ,Water depth ,Ciencias Biológicas ,DEVELOPMENT ,Habitat ,PHENOTYPIC PLASTICITY ,GROWTH ,Animal Science and Zoology ,Desiccation ,Ecology, Evolution, Behavior and Systematics ,CIENCIAS NATURALES Y EXACTAS - Abstract
Desiccation exposes tadpoles to a decrease in habitat size due to a reduction in water depth and surface area. We tested the effect of surface area and water depth on growth and development of tadpoles of Physalaemus albonotatus and whether habitat size effects are constant over the larval period. We performed a 2 × 2 factorial design: two water depths and two surface areas. We measured tadpoles at 15 and 30 days after starting the experiment, and recorded weight and time to metamorphosis. Our results indicate that habitat size influences the morphology, growth, and development of tadpoles and that the response changes during development. At 15 days, tadpoles reared in shallow water had reduced their morphological variables and developmental stage, whereas tadpoles reared in enclosures with different surface areas showed no differences. At 30 days, tadpoles reared in enclosures with small surface areas had increased their body length, body height, and developmental stage, whereas tadpoles reared in different water depths showed no differences. Tadpoles reared in small surface areas reached metamorphosis earlier than tadpoles reared in large surface areas. The results suggest that during ontogeny the surface area and water depth had different influence in the phenotypic plasticity of tadpoles. Fil: Gómez, Valeria Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentina Fil: Kehr, Arturo Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentina
- Published
- 2019
- Full Text
- View/download PDF
5. The effect of chemical signal of predatory fish and water bug on the morphology and development of Elachistocleis bicolor tadpoles (Anura: Microhylidae)
- Author
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Arturo Ignacio Kehr and Valeria Isabel Gómez
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Elachistocleis bicolor ,Plant Science ,Biochemistry ,Predation ,Ciencias Biológicas ,Predatory fish ,PHENOTYPIC PLASTICITY ,parasitic diseases ,Genetics ,PREDATORS ,TADPOLEST ,Molecular Biology ,Predator ,Ecology, Evolution, Behavior and Systematics ,Phenotypic plasticity ,Larva ,biology ,Ecology ,fungi ,Cell Biology ,Bioquímica y Biología Molecular ,biology.organism_classification ,Tadpole ,Animal Science and Zoology ,Microcosm ,CIENCIAS NATURALES Y EXACTAS - Abstract
Changes in environmental conditions can induce organisms to alter their morphology, behavior and life history. Predation is an important factor in many aquatic communities and can strongly select for anti-predator responses. In the present work, we examined the responses in morphology, growth rate and development rate of Elachistocleis bicolor tadpoles raised in the presence of chemical cues from two different predators: a water bug (Belostoma elongatum) and a fish (Moenkausia dichroura). The experiment was performed in microcosm conditions. The experimental design consisted of three treatments: chemical cues from fish, cues from water bugs and a control group. Each treatment was replicated 30 times. Each container held a single larva. The main results were: (1) there were significant differences in body depth between the predator treatments (fish vs. water bug) and between the control group and the water bug treatment, (2) there were significant differences in tail depth between predator treatments (fish vs. water bug) and between the control group and the fish treatment, (3) there were no significant differences in the growth rate and developmental rate among the treatments. Our results suggest that the presence of predaceous fish and water bugs cause different effects on tadpole morphology. In the presence of water bugs, tadpoles decreased body depth, whereas in the presence of fish tadpoles increased tail depth. These responses could be related to the way in which predators capture their prey. Predator chemical cues did not have any detectable effect on the growth rate and development rate of E. bicolor tadpoles. Fil: Gómez, Valeria Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentina Fil: Kehr, Arturo Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentina
- Published
- 2012
- Full Text
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6. Influence of density and predators on metamorphic size in Rhinella schneideri tadpoles raised in mesocosm conditions
- Author
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Arturo Ignacio Kehr and Valeria Isabel Gómez
- Subjects
media_common.quotation_subject ,Density ,Trade-off ,Plant Science ,Phenotypic plasticity ,Body size ,Biochemistry ,Predation ,Mesocosm ,purl.org/becyt/ford/1 [https] ,Ciencias Biológicas ,Rhinella schneideri ,Genetics ,Metamorphosis ,purl.org/becyt/ford/1.6 [https] ,Molecular Biology ,r-strategist ,Ecology, Evolution, Behavior and Systematics ,media_common ,Larva ,biology ,Ecology ,Cell Biology ,Bioquímica y Biología Molecular ,biology.organism_classification ,Predators ,Animal Science and Zoology ,Tadpoles ,CIENCIAS NATURALES Y EXACTAS - Abstract
Amphibians exhibit extreme plasticity in the timing of metamorphosis, and several species respond to water availability, accelerating metamorphosis when their ponds dry. We analyzed the plasticity of the developmental response to water volume in Rhinella schneideri tadpoles. We raised tadpoles in mesocosm. Covariation between body size atmetamorphosis and timing of development was positive. Nevertheless, the first approximately 53% of the metamorphoses finishing the cycle required between 34 and 56 days, and the covariation between body size at metamorphosis and timing of development was negative. For these tadpoles, the larval density and the presence of predators did not significantly affect their mass to metamorphosis. Nevertheless, predators affected time to metamorphosis. For the remainder of the tadpoles that reached metamorphosis at > 56 days, the relationship between body size at metamorphosis and timing of development was positive. For these tadpoles, larval density was important for mass at metamorphosis and presence of predators was also important for time to metamorphosis. Two dominant features were observed: (i) approximately 53% of metamorphs had morphological features similar to individuals developing in desiccating ponds, and (ii) the other individuals had morphological characteristics comparable to metamorphs developing in an unchanging environment. Fil: Kehr, Arturo Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentina Fil: Gómez, Valeria Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentina
- Published
- 2014
7. Interaction between competitors and predators and its effects on morphological and behavioural defences in Scinax nasicus tadpoles
- Author
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Valeria Isabel Gómez and Arturo Ignacio Kehr
- Subjects
Scinax nasicus ,Larva ,biology ,Ecology ,Ecología ,biology.organism_classification ,Tadpole ,Predation ,Characidae ,Belostomatidae ,Ciencias Biológicas ,Behavioral Neuroscience ,CONSPECIFICS ,MORPHOLOGICAL TRAITS ,TADPOLES ,Animal Science and Zoology ,BEHAVIOURAL TRAITS ,PREDATORS ,Microcosm ,Predator ,CIENCIAS NATURALES Y EXACTAS ,SCINAX NASICUS - Abstract
Predation affect the behaviour of organisms, and the number of conspecifics can influence the perception of predation risk. Two main types of traits, morphological and behavioural, are involved in the induced defences of many organisms. Here, we examined the influence of chemical cues of the predators Belostoma elongatum (Hemiptera, Belostomatidae) and Moenkhausia dichroura (Characiformes, Characidae) on the morphology, growth, development and activity of Scinax nasicus larvae. Our main goal was to determine whether the investment in morphological or behavioural defences varied according to the number of conspecifics and to the chemical cues of predators. To this end, we performed two experiments under microcosm conditions. In experiment 1, we determined morphological defences in tadpoles by analyzing changes in morphology, growth rate and development rate, whereas in experiment 2, we determined behavioural defences by analyzing changes in the activity of tadpoles. The experimental design consisted of two tadpole densities, with and without chemical cues of predators. We found that: 1) larval morphology, growth and development were significantly affected by density; 2) the chemical cues of the predators did not influence the morphology, growth or development of tadpoles; 3) tadpoles at high densities were more active than those at low densities; 4) tadpoles decreased the activity in the presence of chemical cues of M. dichroura; and 5) tadpoles increased the activity in the presence of chemical cues of B. elongatum. Our results suggest that density is a determinant factor of tadpole morphology of and that Scinax nasicus larvae respond to predators with behavioural defences, which vary according to the type of predator. Fil: Gómez, Valeria Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Centro de Ecologia Aplicada del Litoral (i); Argentina; Fil: Kehr, Arturo Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Centro de Ecologia Aplicada del Litoral (i); Argentina
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- 2013
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8. Plasticidade morfológica e de desenvolvimento em larvas de Physalaemus santafecinus (Anura: Leiuperidae) em resposta a estímulos químicos de diferentes predadores
- Author
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Valeria Isabel Gómez and Arturo Ignacio Kehr
- Subjects
Larva ,biology ,Ecology ,media_common.quotation_subject ,biology.organism_classification ,Hydrophilidae ,Predation ,Characidae ,Developmental plasticity ,Animal Science and Zoology ,Physalaemus santafecinus ,Metamorphosis ,Predator ,media_common - Abstract
Morphological and developmental plasticity in larvae of Physalaemus santafecinus (Anura: Leiuperidae) in response to chemical cues of different predators. Many antipredator responses are mediated or induced by the ability of the prey to identify chemical cues of predators. The presence of chemicals produced by predators may alert tadpoles to the presence of the predators, and a heightened response to alarm cues or predator presence may increase the possibility of prey survival. We examined changes in morphology, and growth and development rates of Physalaemus santafecinus tadpoles reared in the presence of chemical cues of water beetles (Hydrophilidae) and a fish (Characidae). We recorded the time to metamorphosis, as well as weights of metamorphic individuals to determine if the larval stage is accelerated. The experiments were performed under microcosm conditions, with three treatments—chemical cues from fish, water beetles, and a control group. Each treatment was replicated 30 times. To obtain independent data from different variables, treatments were conducted on individual larvae in separate containers. The principal results were, as follow. (1) Larval morphology was significantly affected by the presence of a predator. (2) Control tadpoles were significantly larger than those subjected to the other two treatments (cues of water beetles and fish). (3) Growth and development rates did not differ significantly among any treatments. (4) Neither time to metamorphosis nor weights of metamorphs varied significantly among treatments. Our results suggest that tadpoles are able to perceive predators by chemical cues released in the water, and P. santafecinus tadpoles alter their morphology to chemical cues that indicate predation. However, chemical cues of predators had no detectable effect on growth rate and developmental rates of these tadpoles.
- Published
- 2011
- Full Text
- View/download PDF
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