Dinâmica de interações tróficas em frutos de Piptadenia gonoacantha (Mart.) Macbr. (Fabaceae: Mimosoideae)

Abstract

Studying how organisms interact with each other through trophic webs in an ecosystem is of great importance, not only for uncovering unreported species and behaviors but also for understanding important and applicable ecological processes such as the natural population control of a particular species over the other, known as biological control. In the first manuscript, we describe a source food web based on the Piptadenia gonoacantha plant, the fruit and seed consuming insects and their primary and secondary parasitoids (hyperparasitoids). In addition, we analyze the relationships of these insects with the resource traits, such as area and biomass. The results of this manuscript showed that the food web has a total of 21 species, six species of herbivores insects, 14 species of parasitoids and one hyperparasitoid species. The food web was compartmentalized in two subwebs, where the parasitoids interact with only two herbivores species. In addition, the results showed that the resource traits exert influence on the insects and on the food web complexity, where larger fruits generate a benefit for them. In the second manuscript, we describe the interactions strenghts between the species of this food web. This manuscript shows that the strongest and most significant interaction of this web is from the seed consumer species Acanthoscelides clitellarius with the resource. Lepidoptera presented a significant interaction value with the number of predated seeds, but did not respond to seed biomass. Among the parasitoids interactions and their hosts, the highest values were for A. clitellarius parasitoids, especially for three parasitoids interactions, Horismenus sp. 1, Eurytoma sp. 1 and Eurydinoteloides sp. 1. However, the estimated values were not significant. In addition, these three parasitoids species has been shown to respond to the resource indirect effects. In conclusion, this dissertation described a food web relatively rich in species of fruit and seed consumers insects and their parasitoids, as well as the existing interaction strengths, showing that resource traits exert a positive influence on the complexity of this food web.