Herbivory and leaf traits in six Caatinga plant species from Northeastern Brazil

Abstract

We evaluated the herbivory intensity on species Handroanthus spongiosus, Tabebuia roseoalba, Dalbergia cearensis, Pterocarpus ternatus, Eugenia pistaciifolia, and Eugenia rigida occurring in the semi-arid Caatinga vegetation of Southwestern Bahia State, Northeastern Brazil. Additionally, we investigated leaf traits that can protect plants against herbivores, such as secondary compounds (presence/absence of alkaloids, saponins, and flavonoids), physical defenses (leaf hardness and presence/absence of trichomes and thorns), and leaf longevity. From January to May 2013, leaves from 20 individuals of each species were collected and their respective herbivory intensities were measured using Dirzo & Dominguez’s herbivory index. The same individuals were also followed monthly for determination of leaf longevity, and species were then classified as deciduous or perennial. Herbivory intensity and leaf hardness were significantly different among species. Herbivory intensity was higher in P. ternatus. The highest leaf hardness values and the lowest herbivory intensity values were found in E. pistaciifolia and E. rigida. Both Eugenia species were classified as perennial, while the other four species were classified as deciduous. Alkaloids and saponins were found in all studied species. Our results indicate that the presence of mechanic defenses is more effective against herbivores than the presence of chemical ones. The herbivory intensity in deciduous species from the Brazilian Caatinga is similar to that which is reported to other dry forests in the world.