Seja DIFERant: etnomirmecologia e perspectivas agroecológicas no controle de formigas cortadeiras

Abstract

Social movement Peasants’ environmental representations in relation to leaf-cutting ants (Atta e Acromyrmex) may be related to their particular familiarity with and formation in agroecology, implying directly on the kind of control method used to reduce agricultural losses triggered by these insects. Considering that agroecology values common knowledge, it is extremely necessary that these are recognized. The present study aimed to: (i) investigate the relation between Assentamento Dênis Gonçalves (ADG) peasants’ socioeconomic profile and agroecological knowledge with environmental representations and leaf-cutting ant control methods; (ii) evaluate, under laboratory conditions, the repellent potential of extracts, cow urine at 10%, allopathy and homeopathy of ants in Acromyrmex subterraneus (Forel, 1893). Information about socioeconomic characterization, agroecological knowledge, and control methods for leaf-cutting ants was registered through semi-structured interviews with 80 peasants between september and december 2018. Through a Multiple Correspondence Analysis (MCA) it was identified a similarity between the profiles of older peasants who had never studied, regardless of gender, who do not know about agroecology, these have a negative conception about the ants’ function in the environment and use chemical baits as a control method. Another similarity was verified between the profiles of younger peasants who know about agroecology, positively attribute ecological functions for ants in the environment and use agroecological control methods. Furthermore, it was performed two experiments for the agroecological methods most used by the peasants, both analysed through a Generalized linear mixed model (GLMM). on the first one, to evaluate if the extracts promote a reduction in the total flow of A. subterraneus workers, colonies were submitted to foraging in a plastic trail demarcated with three segments (Pre-Barrier, Barrier and Post-Barrier, respectively), where in the Barrier it was applied 30mL of the referred extracts, accounting the total flow of workers over and on the side of the trail in each segment during one minute, for each 5 minutes, during 1 hour. It was observed a detour in the total flow in the Barrier segment for all applied extracts, the total flow was concentrated in the side of the trail, differing from the other segments, where the flow concentrated over the the trail for all treatments. It was also possible to verify a lower amount of carried leaves on the trail with isopathy. On the second experiment, with the objective of evaluate the effect of application of the extracts in workers’ leaf selection, it was adopted a Y trail system with branches connected to a rectangular arena with 50 leaf discs, in such a way that leaf discs containing cow urine and isopathy extracts were offered simultaneously. It was verified a lower proportion of carried leaf discs for both applications. It is concluded that schooling, age and access to knowledge promote different environmental representations and actions in relation to the control methods utilized in ADG. The isopathy and cow urine were the most efficient methods of repelling A. subterraneus. The effectivity of isopathy is attributed to the possible presence of alarm pheromones in its composition, which are crushed for their preparation. For cow urine, the odor may be the main repellent, in view of the ants’ high chemical sensibility. The richness and complexity of traditional knowledge portrayed here reinforce how Agroecology can be a powerful tool allied to promoting an environmentally sustainable agriculture.