Search results for "Zoología"
showing 10 items of 134 documents
Ecological specialization to fluctuating resources prevents long-distance migratory raptors from becoming sedentary on islands
2013
[Background]: The adaptive transition between behavioral strategies, such as the shift from migratoriness to sedentariness, remains an outstanding question in evolutionary ecology. Density-dependent variation in the age of first breeding has been proposed as a feasible mechanism through which long-lived migratory birds with deferred sexual maturity should become sedentary to persist on islands. Although this pattern seems to hold for most raptors and herons, a few exceptions have been identified. One of these exceptions is the Eleonora's falcon, a long-distance migratory bird, which shows one of the most peculiar adaptations in the timing of reproduction and food requirements among raptors.…
Development of an antibody-based capture enzyme-linked immunosorbent assay for detecting echinostoma caproni (trematoda) in experimentally infected r…
2003
The present study reports on the development of a coproantigen capture enzyme-linked immunosorbent assay (ELISA) for detecting Echinostoma caproni in experimentally infected rats. The capture ELISA was based on polyclonal rabbit antibodies that recognize excretory–secretory (ES) antigens. The detection limit of pure ES was 3 ng/ml in sample buffer and 60 ng/ml in fecal samples. The test was evaluated using a follow-up of 10 rats experimentally infected with 100 metacercariae of E. caproni, and the results were compared with those of other diagnostic methods such as parasitological examination and antibody titers determined by indirect ELISA. Coproantigens were detected in all the infected r…
Kinetics of antibodies and antigens in serum of mice experimentally infected with echinostoma caproni (trematoda: echinostomatidae)
2005
The present study reports on the kinetics of antibodies and antigens in serum of mice experimentally infected with 75 metacercariae of Echinostoma caproni during the first 12 wk postinfection (wpi). Antibody titers in the serum of mice were determined by an indirect enzyme-linked immunosorbent assay (ELISA) using excretory/secretory (ES) antigens of E. caproni. The early detection of antibodies against ES antigens of E. caproni is feasible using indirect ELISA. Mice developed significant antibody responses at 2 wpi, and the values progressively increased until the end of the experiment. This may be related to the intestinal absorption of adult worm antigens that induces humoral responses. T…
Living on the edge: assessing the extinction risk of critically endangered Bonelli’s eagle in Italy
2012
Background: The population of Bonelli’s eagle (Aquila fasciata) has declined drastically throughout its European range due to habitat degradation and unnatural elevated mortality. There are less than 1500 breeding pairs accounted for in Europe, and the species is currently catalogued as Critically Endangered in Italy, where the 22 territories of Sicily, represent nearly 95% of the entire Italian population. However, despite national and European conservation concerns, the species currently lacks a specific conservation plan, and no previous attempts to estimate the risk of extinction have been made. Methodology/Principal Findings: We incorporated the most updated demographic information ava…
Scavengers on the move: behavioural changes in foraging search patterns during the annual cycle
2013
Background: Optimal foraging theory predicts that animals will tend to maximize foraging success by optimizing search strategies. However, how organisms detect sparsely distributed food resources remains an open question. When targets are sparse and unpredictably distributed, a Lévy strategy should maximize foraging success. By contrast, when resources are abundant and regularly distributed, simple Brownian random movement should be sufficient. Although very different groups of organisms exhibit Lévy motion, the shift from a Lévy to a Brownian search strategy has been suggested to depend on internal and external factors such as sex, prey density, or environmental context. However, animal re…
Nest Site Selection by Kentish Plover Suggests a Trade-Off between Nest-Crypsis and Predator Detection Strategies
2014
Predation is one of the main causes of adult mortality and breeding failure for ground-nesting birds. Micro-habitat structure around nests plays a critical role in minimizing predation risk. Plovers nest in sites with little vegetation cover to maximize the incubating adult visibility, but many studies suggest a trade-off between nest-crypsis and predator detection strategies. However, this trade-off has not been explored in detail because methods used so far do not allow estimating the visibility with regards to critical factors such as slope or plant permeability to vision. Here, we tested the hypothesis that Kentish plovers select exposed sites according to a predator detection strategy,…
POPULATION STRUCTURE OF ANISAKIS SIMPLEX (NEMATODA) IN HARBOR PORPOISES PHOCOENA PHOCOENA OFF DENMARK
2004
The population structure and habitat selection of Anisakis simplex in 35 harbor porpoises off Denmark are described. The nematodes were collected from the stomach and duodenal ampulla and were categorized as third-stage larvae, fourth-stage larvae, subadults, and adults. The porpoises harbored 8,043 specimens of A. simplex. The proportion of adults and subadults increased with infrapopulation size. The number of development stages across infrapopulations covaried significantly (Kendall's test of concordance). Concordance was higher in hosts with the highest intensities than in those with low and medium intensities. All stages occurred mainly in the forestomach, but this trend was stronger f…
Development and pathology of echinostoma caproni in experimentally infected mice
2007
In the present article, several parasitological features of mice, each experimentally infected with 75 metacercariae of Echinostoma caproni (Trematoda: Echinostomatidae), were studied during the first 12 wk postinfection. Moreover, the early pathological responses also were analyzed and compared with data previously published on other host species of E. caproni to gain further insight into the factors determining worm rejection or establishment of chronic infections. The results obtained show that the pattern of E. caproni infection in mice is consistent with a highly compatible host–parasite system. This combination is characterized by a high worm establishment, high egg output, and long s…
A review of virus infections of cataceans and the potential impact of morbilliviruses, poxviruses and papillomaviruses on host population dynamics.
1999
Viruses belonging to 9 families have been detected in cetaceans. We critically review the clinical features, pathology and epidemiology of the diseases they cause. Cetacean morbillivirus (family Paramyxoviridae) induces a serious disease with a high mortality rate and persists in several populations. It may have long-term effects on the dynamics of cetacean populations either as enzootic infection or recurrent epizootics. The latter presumably have the more profound impact due to removal of sexually mature individuals. Members of the family Poxviridae infect several species of odontocetes, resulting in ring and tattoo skin lesions. Although poxviruses apparently do not induce a high mortali…
Kinetics of echinostoma caproni (trematoda: echinostomatidae) antigens in feces and serum of experimentally infected hamsters and rats
2004
This study reports on the kinetics of antibody production to Echinostoma caproni and the dynamics of antigens in feces and sera in 2 experimental hosts (hamsters and rats) that display different degrees of susceptibility with this echinostome. Echinostoma caproniproduced chronic infections in hamsters, whereas rats lost the infection at 49-56 days postinfection (DPI). Hamsters developed higher antibody responses than rats, probably in relation to different intestinal absorptions of worm antigens in each host species. The levels of coproantigens were indicative of the course of infection in each host. Positive coproantigen levels were detected at 1-2 DPI in both hosts, and the values remaine…