Aristóbulo del Valle, Argentina
Aristóbulo del Valle, Argentina

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Marco M.V.P.,CONICET | Marco M.V.P.,Laboratorio Of Zoologia Aplicada Anexo Vertebrados | Larriera A.,Laboratorio Of Zoologia Aplicada Anexo Vertebrados | Larriera A.,National University of Santa | And 3 more authors.
Journal of Herpetology | Year: 2015

Flooding and predation are the two major causes for the decline in hatching rate and hatchling survival in crocodilian species. Recently, Solenopsis invicta (Red Fire Ant) has been recognized as a formidable invasive species, causing changes in wild populations of reptiles. Because of the elevated densities of Red Fire Ants present in Caiman latirostris (Broad-Snouted Caiman) nests during the breeding season, experiments in captivity and in the wild were performed to verify if the presence of S. invicta affects nest success or care of eggs and the hatching-assistance behavior of C. latirostris females. Hatchling survival from eggs incubated in a lab setting in the presence of Red Fire Ants decreased by approximately 10% compared to nests without ants. In a second experiment performed in the wild, the presence of Red Fire Ant resulted in a 43% reduction in nest success including direct (14.5%) and indirect (28.5%) effects. Our study confirmed that Red Fire Ants negatively affect C. latirostris nest success, directly because Red Fire Ants attack and cause the hatchling's death after pipping and indirectly by preventing females from caring for eggs, providing hatching assistance, and maintaining nests. © 2015 Society for the Study of Amphibians and Reptiles.


Schaumburg L.G.,CONICET | Schaumburg L.G.,Laboratorio Of Zoologia Aplicada Anexo Vertebrados | Poletta G.L.,CONICET | Poletta G.L.,Laboratorio Of Zoologia Aplicada Anexo Vertebrados | And 3 more authors.
Ecotoxicology and Environmental Safety | Year: 2012

The Micronucleus test (MN) and Comet assay (CA) are currently the most widely used methods that allow the characterization of DNA damage induced by physical and chemical agents in wild species. The continuous expansion of the cultivated areas in Argentina, since the introduction of transgenic crops, mainly soy, in association with the increased use of pesticides, transformed deeply the natural environments where the lizard Tupinambis merianae (tegu lizard) occurs. Despite the fact that reptiles have shown to be excellent bioindicators of environmental contaminants, there is no record of genotoxicity studies in T. merianae. The aim of the present study was to adjust the MN test and CA protocols to be applied in erythrocytes of T. merianae, and determine the baseline values of DNA damage in this species. We used 20 adult lizards (10 males: 10 females) from Estación Zoológica Experimental "Granja La Esmeralda" (Santa Fe, Argentina). Peripheral blood samples were collected from all animals and the MN test and CA applied according to the protocols established for other reptilian species. We test critical parameters of CA protocol (cell density, unwinding and electrophoresis times) using increasing concentrations of H2O2 (10, 25 and 50μM) as a known genotoxic agent to induce DNA damage. Based on this, we determined the most suitable conditions for the CA in this species: a cell density of 4×103 erythrocytes per slide, 10min of unwinding and 15min of electrophoresis at 0.90V/cm approximately. The baseline frequency of micronuclei (BFMN=MN/1000 erythrocytes counted) determined for this species was 0.95±0.27 and the basal damage index (BDI: calculated from 100 comet images classified in arbitrary units)=103.85±0.97. No differences were observed between sexes in the BFMN or BDI (p>0.05), and no relation was found between baseline values and length or weight of the analyzed animals (p>0.05). These results demonstrated the sensitivity of both biomarkers of genotoxicity to be applied in erythrocytes of this species, with baseline values comparable to those reported in other reptilian species. These results allow us to propose the tegu lizard for future in vivo studies to assess the genotoxicity of different agents, including those possibly affecting it in its natural geographic distribution. © 2012 Elsevier Inc.

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