Estrutura de redes de interações ecológicas entre dieta, parasitos e lagartos da região do Parque Nacional da Chapada das Mesas

Abstract

The complex web of interactions that structures biotic communities is the focus of study of ecological networks, a science that aims to describe and evaluate patterns of interactions between species and their effects on ecological processes. These processes are determined by the food resources between a small group, populations or communities of organisms co-occurring in space-time, and network analysis stands out as a valuable tool for demonstrating the path of energy circulating within ecosystems. On average, about 35% of the energy that flows between these networks occurs via parasitism. Thus, lizards, which are essential organisms for the ecological dynamics of natural processes and occupy a key position in the trophic chain, where they act as primary and secondary predators and/or as prey, are an important taxon to investigate in terms of their diet and that of their associated endoparasites, since these organisms use various reproductive strategies and strategies for obtaining food. The present study is the first research for the Cerrado biome with ecological network approaches using lizards as models, which aimed to evaluate and understand how the networks of host-parasite interactions and diet of lizards from the Chapada das Mesas National Park region are structured. Bipartite nets (host-parasite net and predator-prey net) were constructed, in addition to the lizard species, the nets were set up with eight species of endoparasites and 29 categories of food items. The networks did not present a well-defined nesting pattern or modularity, with a diffuse pattern with low values of modularity and more pronounced nesting, although not very expressive, indicating that there are species that are specialists, following the same path in the network as the generalist species and few specialist species interacting with other specialists. We identified the lizard species that played a functional role in structuring the topology of the networks and network modules. We also found that the habits related to the lizards' foraging strategies and seasonality influenced the structuring of the nets. This is because the opportunistic and generalist lizard species occupied a central position in the parasite-host networks and in the predator-prey networks, in both seasons. The differences in the foraging behavior of the lizards, combined with the breadth of niches may explain why lizards such as T. hispidus, A. ameiva and A. ocellifera had a greater diversity of parasites and the highest consumption of prey, especially during the dry season. Thus, we found evidence that the habits related to the lizards' foraging strategies and seasonality are related to their positions, both in the networks between parasite and hosts and between lizard predators and their prey, determining all the metrics of centrality of the networks.