Avaliação da herbivoria nas folhas de Conocarpus erectus L., Laguncularia racemosa (L.) C. F. Gaerth e Rhizophora mangle L, em ambiente de mangue, Marechal Deodoro, Alagoas

Abstract

Mangroves are characterized as transitional coastal ecosystems between the terrestrial and marine environments that occupy the tropical and subtropical coasts, formed by plant species that serve as shelter and food for numerous organisms, among which invertebrate herbivores important for this ecosystem stand out. The present work aimed to investigate the invertebrate herbivores that act on the species Conocarpus erectus L., Laguncularia racemosa (L.) CF Gaerth and Rhizophora mangle L., and the species with the highest rate of herbivory, in a mangrove environment, in Marshal Deodoro, Alagoas. The research was performed in April, May, and June 2019 in the area of the Estuarine-Lagunar Mundaú/Manguaba Complex (CELMM). Leaves were collected from the matrices of the species C. erectus, L. racemosa, and R. mangle, and the quantification of the herbivory index of each species was performed qualitatively and quantitatively. In the qualitative evaluation, the herbivores were identified (chewing, sucking, scraping, and mining) according to the type of damage in the leaf área, and in the quantitative evaluation, the herbivory rate was calculated, through the consumption of the whole plant or part of it, identifying the percentage of damage intensity that varies from 0 to 5. The ImageJ program was used for these analyses. Rainfall data were collected to relate to the research variables. Descriptive statistics were used for data analysis using Excel version 2016 software. The invertebrate herbivores identified in the species Conocarpus erectus L., Laguncularia racemosa (L) CF Gaerth, and Rhizophora mangle L. are of the chewing, sucking, and mining types, whereas the chewers are concentrated in the leaves of C. erectus and L. racemosa and R. mangle there is a higher occurrence of sucking herbivores; The species with the highest herbivory rate is C. erectus, followed by L. racemosa and R. mangle. And the herbivory index of the species C. erectus and L. racemosa present a higher concentration of leaves in class 3 (12.1 to 25%) of the area consumed by herbivores, regardless of the months. The herbivory index of the R. mangle species corresponds to class 1 (0.1 to 6%) of the area consumed by herbivores in all analyzed months; The increase in the volume of rainfall promotes a decrease in herbivores and consequently a reduction in damage rates by herbivory.