Ecological indices of phytophagous Hemiptera and their natural enemies on Acacia auriculiformis (Fabales: Fabaceae) plants with or without dehydrated sewage sludge application in a degraded area

Authors: DOURADO, LUAN - Universidade Federal De Minas Gerais; LEITE, GERMANO L. - Universidade Federal De Minas Gerais; SOARES, MARCUS - Universidade Federal De Minas Gerais; TEIXEIRA, GUSTAVO - Universidade Federal De Minas Gerais; SILVA, FARLEY - Universidade Federal De Minas Gerais; SAMPAIO, REGYNALDO - Universidade Federal De Minas Gerais; ZANUNCIO, JOSE - Universidade Federal De Vicosa; Legaspi, Jesusa

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/22/2020
Publication Date: 8/17/2020
Citation: Dourado, L.R., Leite, G.D., Soares, M.A., Teixeira, G.L., Silva, F.W., Sampaio, R.A., Zanuncio, J.C., Legaspi, J.C. 2020. Ecological indices of phytophagous Hemiptera and their natural enemies on Acacia auriculiformis (Fabales: Fabaceae) plants with or without dehydrated sewage sludge application in a degraded area. PLoS One. 15(8):e0237261. https://doi.org/10.1371/journal.pone.0237261.
DOI: https://doi.org/10.1371/journal.pone.0237261

Interpretive Summary: The application of dehydrated sewage sludge (DSS) around newly planted Acacia trees is a possible treatment for enhanced recovery of soil nutrients in degraded areas in Brazil. With the application of DDS, there should be a concomitant increase in the plant and insect populations around the trees. Scientists at Universidade Federal dos Vales do Jequitinhonha e Mucuri, Universidade Federal de Minas Gerais, Universidade Federal do Acre, and Universidade Federal de Viçosa, in collaboration with scientists at the USDA-ARS, Center for Medical, Agricultural and Veterinary Entomology, Tallahassee, Florida, conducted a two year study to assess the growth of the plant and insect populations as soil bioindicators within the immediate vicinity of DDS treated and non-treated trees. The plants around the DSS treated trees showed an increased population and growth along with more abundant insect populations as compared with those trees without DSS. These results indicate that the use of DSS is an important treatment that can increase the recovery of degraded soil areas as reflected by an increase in bioindicators such as soil litter and insect populations.

Technical Abstract: Soil fertilization with dehydrated sewage sludge (DSS) accelerates the recovery process of degraded areas by improving nutrient concentration, and favors the development of trophic webs with pioneer plants such as Acacia auriculiformis A. Cunn. ex Beth (Fabales: Fabaceae), phytophagous Hemiptera, predators, and protocooperanting ants. This study aimed to evaluate the development and production of A. auriculiformis litter with or without dehydrated sewage sludge application and the ecological indices of sucking insects (Hemiptera), their predators and protocooperating ants, as bioindicators, in a degraded area for 24 months. Complete randomization was applied for two treatments (with or without application of dehydrated sewage sludge) in 24 replications (one repetition = one plant). We evaluated the number of leaves/branch and branches/plant, percentage of soil cover (litter), ecological indices of phytophagous Hemiptera, their predators, and protocooperating ants. The plants of A. auriculiformis, that were applied with dehydrated sewage sludge, had superior development when compared to plants where DSS were not applied. The highest abundance and richness of phytophagous Hemiptera species and Sternorrhyncha predators occurred on A. auriculiformis plants that were applied with dehydrated sewage sludge. The increase in richness of species of protocooperanting ants that established mutualistic relationships positively influenced the phytophagous Hemiptera. The use of A. auriculiformis, with application of dehydrated sewage sludge, can increase recovery of degraded areas due to its higher soil cover (e.g., litter) and results in higher ecological indices of phytophagous Hemiptera and their predators.