Browsing by Author "Cifuentes Castro, Camila Andrea"

Now showing 1 - 1 of 1
  • Thumbnail Image
    Item
    Evaluación de la Variación Espacial de la Riqueza y Abundancia en las Especies de Pulgas (Siphonaptera) en Abrothrix Olivacea (Waterhouse, 1839).
    (Universidad de Concepción, 2023) Cifuentes Castro, Camila Andrea; Moreno Salas, Lucila del Carmen
    Knowing the distribution of parasites is relevant from the point of view of public health. Although, there are various hypotheses to explain the distribution of richness and abundance of species (eg "center of abundance hypothesis", "optimum abundance hypothesis", "latitudinal hypothesis", "latitudinal diversity gradient", among others). ), most of them have been evaluated in free-living vertebrates, while insufficient evidence has been found to support these hypotheses for invertebrates, and even less so for parasitic species. In the hypotheses indicated, the environmental factors would be those that determine the distribution of the species, however, in the case of the parasitic species, the availability of resources represented by the different host species that they parasitize become important. Given the generalist or specialist behavior of parasite species, differences in the distribution of parasite species richness could be generated through the distribution of hosts. Fleas are parasites that inhabit the entire world, including in deserts and Antarctica, they are very important epidemiologically, since they transmit pathogenic microorganisms responsible for about 45 diseases, affecting both humans and animals, forming part of zoonotic cycles. They parasitize 95% of mammals, including cricetid rodents, which have a greater wealth of fleas. In the present investigation, the species Abrothrix olivacea (Waterhouse, 1839) and its fleas are used as a study model to evaluate the factors that determine the distribution of abundance and richness of flea species in this rodent throughout its distribution in Chile. . A. olivacea is one of the rodents with the widest distribution in Chile, ranging from the border with Peru to Tierra del Fuego. Through its wide distribution, this rodent inhabits different ecological regions and has close interactions with other rodent species that may influence the distribution of abundance and richness of fleas it possesses. As a hypothesis, it was proposed that: 1) The richness of fleas in A. olivacea is determined by the number of species of rodents with which it cohabits throughout its geographical distribution, hoping to find that A. olivacea presents a greater richness of fleas in localities where it cohabits with a greater number of species, 2) The reproduction of fleas is determined by humidity and temperature, where at lower temperatures and humidity reproduction decreases, therefore, it is expected to find less abundance in environments where these parameters environmental are minor; and 3) There is interspecific competition between fleas that cohabit in a host, so it is expected that the species that make up a community co-occur less than expected by chance. The first hypothesis was evaluated at the level of component communities, for which the richness and abundance of fleas in each of the localities was estimated, adding data on temperature and humidity (minimum and maximum) of each of them, and the richness of rodent species that live in sympatry with A. olivacea. The variables were related through a generalized linear model applying the Poisson function. For the second hypothesis, a statistical analysis of GLM was carried out using the Poisson function, relating temperature and humidity of the localities where the 5 most abundant species were distributed and with the widest distribution in the sampling. For the third hypothesis, the existence of patterns of co-occurrence of flea species at the infracommunity level was evaluated through the C-score index. The results indicate that there is no statistically significant relationship between the number of rodent species that cohabit with A. olivacea and flea richness. The distribution of flea species richness showed no association with environmental factors along the geographic distribution of A. olivacea. A positive relationship was found between abundance of fleas and richness. For C-score, an observed value higher than expected was obtained, which would indicate that the species do not interact in a positive or negative way, but that the structure of the communities is random. Therefore, all three hypotheses are rejected. This study contributed to assess the factors that could determine the distribution of these ectoparasites in A. olivacea and encourages to investigate the effects of other factors not considered in this study.
Síguenos en...