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Simoncini M.S.,CONICET | Simoncini M.S.,Laboratorio Of Zoologia Aplicada | Marco M.V.P.,CONICET | Marco M.V.P.,Laboratorio Of Zoologia Aplicada | And 6 more authors.
Phyllomedusa | Year: 2016

Predation is a major cause of crocodilian egg loss. However, at present, the mechanisms by which predators detect nests is unknown. Previous studies have reported that predators are able to detect prey using both visual and olfactory cues. This study aims to determine the natural predation rate on Broad-snouted Caiman (Caiman latirostris) nests in a "normal" year (i.e., no extreme climatic events) and whether olfactory or visual cues attract predators to caiman nests, and to evaluate the effect of maternal presence on nest predation. In December 2010, we searched for nests in the north of Santa Fe Province, Argentina. Each nest was assigned to one of the following treatments: (1) control nests (nests were observed from a distance to avoid disturbance), (2) visual attraction nests (yellow flagging tapes were tied to vegetation around the nest), (3) olfactory attraction nests (nests were opened, one egg from the clutch was broken, and then the nests were covered again), (4) olfactory attraction from human disturbance (material was manipulated by researchers). The natural predation rate on broad-snouted caiman nests was found to be 21% during the nesting season. Both olfactory and visual cues were associated with increased predation rates, and human disturbance was strongly associated with increased nest predation at terrestrial sites. Predation rates were less at nests attended by female caiman. Management programs that harvest eggs in wild populations (ranching) are predicated on the assumption that removal of some eggs is sustainable, because some will be lost to natural causes (e.g., predation and flooding) and the remaining hatchlings will have improved survival rates. To reduce nest predation of Broad-snouted Caiman between the time when the nest is found and when the eggs are collected, we propose to avoid identification of nest sites with highly visible markings (e.g., flagging tapes tied to vegetation around nests) and to collect eggs immediately after they are found. ©2016 Universidade de São Paulo - ESALQ.

Marco M.V.P.,CONICET | Marco M.V.P.,Laboratorio Of Zoologia Aplicada | Larriera A.,Laboratorio Of Zoologia Aplicada | Larriera A.,National University of Santa | And 4 more authors.
Zoological Studies | Year: 2013

Background: Oviparous vertebrate species are often vulnerable to predation by red imported fire ants (RIFAs, Solenopsis invicta) in natural environments. The necrotic action of the venom can cause localized infections, with subsequent effects on survival and growth. Despite the significant impacts of RIFAs in regions where they have been introduced, very little is known about the competitive mechanisms of RIFAs with other species in their native habitat. We tested whether the survival and growth of hatchlings of the broad-snouted caiman Caiman latirostris were affected by different exposure times to RIFAs. Results: We observed that an increased exposure time to RIFAs caused a decrease in C. latirostris survival. However, the subsequent growth of C. latirostris hatchlings was not affected by the time of exposure to the ants. Conclusions: S. invicta can cause negative effects for other species in places where it is native. The mechanisms of S. invicta toxicity to caimans are not known; these data could help model the effects of S. invicta on C. latirostris survival, in turn fostering a better understanding of wild population dynamics. © 2013 Marcó et al.; licensee Springer.

Simoncini M.S.,CONICET | Simoncini M.S.,Laboratorio Of Zoologia Aplicada | Cruz F.B.,CONICET | Pin C.I.,CONICET | And 2 more authors.
Herpetological Conservation and Biology | Year: 2013

Reproductive biology of Broad-snouted caiman (Caiman latirostris) may be affected by climatic variables. however, it remains unknown which are the specific climatic variables that affect the onset of oviposition, as well as its duration. in this study, we use a series of climatic data corresponding to the preceding four weeks to oviposition to know which of them influence these reproductive characteristics, and we observed that weather conditions of the immediate week prior to oviposition was the most important factor. We found a delay in the onset of oviposition positively associated to the number of days with temperatures below 20° c in the previous weeks. conversely, we found that oviposition starts earlier with the increase of the number of days with temperatures above 33° c during the previous week. additionally, the duration of the oviposition period is longer when the number of days with temperatures above 33° c increases. no relationship was found between the onset of oviposition and the number of storms or the amount of rainfall in the four preceding weeks. We also noted that in seasons when the start of oviposition is delayed, the duration of oviposition of this period is shorter. the onset of oviposition of female C. latirostris may vary by up to three weeks among years. the information obtained here is a useful tool for managing strategies for its predictive power of the timing and duration of oviposition based on climatic information. © 2013. Melina Simoncini. All Rights Reserved.

Ramoni-Perazzi P.,Laboratorio Of Zoologia Aplicada | Soto-Werschitz I.A.,University of Los Andes, Venezuela | Bianchi-Perez G.,University of Los Andes, Colombia | Jones J.,Tetra Tech Inc. | And 4 more authors.
Cotinga | Year: 2014

Field work into the ecology and distribution of Cerulean Warbler Setophaga cerulea, which permitted some of the observations presented here, was supported by a grant from The Nature Conservancy and US Fish and Wildlife Service to JJ and PR-P. Field work in the upper Mocoties basin and in the Chichuy Mucutuy area was supported by the Consejo de Desarrollo Cientifico Humanistico, Tecnologico y de las Artes of Universidad de Los Andes (C-1649-09-01-B to PR-P and MM-R, and C-1713-10-01-D to IAS-W and PR-P, respectively). We are indebted to Edda Perazzi, Juan Fernando Burgos and Raphael Dulhoste for their assistance during the field work. Pascual Soriano identified the bat species predated by the dead Stygian Owl. The final manuscript benefited from comments by Guy Kirwan and Gustavo A. Rodriguez.

Fernandez M.S.,CONICET | Simoncini M.S.,CONICET | Simoncini M.S.,Laboratorio Of Zoologia Aplicada | Dyke G.,UK National Oceanography Center
Naturwissenschaften | Year: 2013

We describe irregularly calcified egg and eggshell morphologies for the first time in nests of the broad-snouted caiman, Caiman latirostris. Research is based on detailed descriptions of 270 eggs from a total sample of 46,800 collected between 2005 and 2011 in Santa Fe Province, Argentina, and encompasses animals from both natural habitats and held in captivity. We discuss possible reasons for the occurrence of eggs with different mineralisation patterns in our extensive C. latirostris field sample and its conservation significance; the chemistry of egg laying in amniotes is sensitive to environmental contamination which, in turn, has biological implications. Based on our egg sample, we identify two caiman eggshell abnormalities: (1) regularly calcified eggs with either calcitic nodules or superficial wrinkles at one egg end and (2) irregularly calcified eggs with structural gaps that weaken the shell. Some recently laid clutches we examined included eggs with most of the shell broken and detached from the flexible membrane. Most type 1 regularly calcified eggs lost their initial calcified nodules during incubation, suggesting that these deposits do not affect embryo survival rates. In contrast, irregularly calcified caiman eggs have a mean hatching success rate of 8.9 % (range 0-38 %) across our sample compared to a mean normal success of 75 %. Most irregularly calcified caiman eggs probably die because of infections caused by fungi and bacteria in the organic nest material, although another possible explanation that merits further investigation could be an increase in permeability, leading to embryo dehydration. © 2013 Springer-Verlag Berlin Heidelberg.

Lopez S.L.,University of Buenos Aires | Aiassa D.,National University of Rio Cuarto | Benitez-Leite S.,National University of Asunción | Lajmanovich R.,CONICET | And 7 more authors.
Advances in Molecular Toxicology | Year: 2012

In South America, the incorporation of genetically modified organisms (GMO) engineered to be resistant to pesticides changed the agricultural model into one dependent on the massive use of agrochemicals. Different pesticides are used in response to the demands of the global consuming market to control weeds, herbivorous arthropods, and crop diseases. Here, we review their effects on humans and animal models, in terms of genotoxicity, teratogenicity, and cell damage. We also stress the importance of biomarkers for medical surveillance of populations at risk and propose the use of biosensors as sensitive resources to detect undesirable effects of new molecules and environmental pollutants. The compatibility of glyphosate, the most intensively used herbicide associated to GMO crops, with an integrated pest management for soybean crops, is also discussed. © 2012 Elsevier B.V.

PubMed | Laboratorio Of Zoologia Aplicada
Type: Journal Article | Journal: Zoo biology | Year: 2012

Sunlight is a key environmental factor in almost all ecosystems, and it is necessary for many physiological functions. Many vertebrates require ultraviolet (UV) radiation to perform different physiological processes. Artificial light is used to supplement UV in captive animals, through appropriate photoperiods and UV wavelengths. Previous studies reported that repeated exposure to artificial UV radiation may cause damage to the immune system. Taking into account the importance of UV effects and the serum complement system, the relationship between them was investigated. The study lasted 90 days and was carried out in plastic chambers. Ninety six broad-snouted caiman (C. latirostris) were assigned to four treatment groups with two replicates each: total darkness (TD), 8hr per day (8hr) and 16hr per day (16hr) of artificial UV/visible light exposure, and normal photoperiod of natural light (NP). Snout-vent length was measured to determine animal growth. Hemolytic assays were performed to evaluate the effects of artificial UV/visible light, TD, and NP on the serum complement system. Results showed that animals grew more in the NP group. The capacity of C. latirostris serum to hemolyze sheep red blood cells was higher in the NP group than when they are maintained in constant light-dark cycles (8 and 16hr) or in TD. These data demonstrate that artificial UV should be considered as a potential hazard for captive crocodilians if it is not properly managed, and this should be taken into account in the general design of facilities for reptilian husbandry.

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