Interaction Of The Aphid-Parasitoid-Ant Network In Plants Associated With An Organic Citrus Grove

Vegetation associated with crops plays a fundamental role in soil management and biological control processes, such as predation and parasitism. In this study, the types of plants associated with a citrus crop were investigated to establish the interactions between the aphid-parasitoid-ant communities and to know the possible aphid reservoirs. Parasitism rates in aphids were calculated and the degree of nesting of these communities was determined through bipartite networks of presence-absence in order to know the matrices of nested species. The results showed two specific species of aphids with the highest parasitism rate, Dysaphis pyri and Shipa maydis, both parasitized by Lysiphlebus testaceipes, one of the most common and abundant parasitoids in citrus. The red aphid-plants were clearly not nested, because the aphids are specialized in exploiting certain type of plant, also the vegetation existing during the sampling season may not have been attractive to the end of their biological cycles, or the densities were low in this period. Therefore, the plants associated with the crop were not reservoirs of aphids. The other two aphid-parasitoid and aphid-ant networks were nested, mostly due to the existence of generalist species of parasitoids and ants (L. testaceipes interacted with 11 species of aphids, and Lasius grandis with 9 species), which indicates that parasitoids and ants are complementary for a suitable biological control in citrus.