Change in herbivore insect communities from adjacent habitats in a transitional region

Abstract

Ecotonal areas between habitats vary in floristic composition and phenological patterns of the vegetation. In these regions, the habitat structure and plant phenology potentially affect the diversity of associated herbivore insects guilds (chewing and sap-sucking). In this study, the following hypotheses were tested in three habitats (cerrado sensu strictu, dry forest and riparian forest) in a CerradoCaatinga transitional area: (1) There is a variation in composition, richness and abundance of herbivore insects associated with the canopy among adjacent habitats; (2) habitats with higher variation in canopy cover support lower richness and abundance of herbivore insects; (3) habitats with more tree species and higher tree density support higher richness and abundance of herbivore insects; and (4) differences in species composition of herbivore insects among adjacent habitats are the main source of diversity in transitional habitats. The community of herbivore insects differed among the habitats, being similar between riparian and dry forests and different from cerrado. Canopy cover variation, richness and density of trees did not influence richness and abundance of chewing herbivores. A negative effect of canopy cover variation was observed in richness and abundance of sap-sucking herbivore insects, and a negative effect of tree density was observed on abundance of sap-sucking herbivore insects. A higher importance of beta diversity among habitats was observed if compared to beta diversity within habitats (54 %). This study points out that strategies of conservation must consider the entire vegetation mosaics to protect a higher number of species, and to keep these regions with high diversity.

Spatio-temporal colour variation of arthropods and their environment

“…In addition, organisms may seek shelter in the gallery forest during the dry season (Marquis et al 2002). However, the low similarity between the composition of insects and spiders between the cerrado and the gallery forest (this study, Leal et al 2015;Moraes 2015) and the much larger cerrado area in comparison to the riverine forests (probably < 10% of the biome; Oliveira-Filho and Ratter 2002) suggest that this is not a common strategy.…”

Diversity of insects associated with two common plants in the Brazilian Cerrado: Responses of two guilds of herbivores to bottom-up and top-down forces

“…Therefore, ants are important elements of the third trophic level and are able to shape the community of insect herbivores on plants (Davidson et al, 2003;Heil & McKey, 2003;Ribas et al, 2003;Fagundes et al, 2005;Rosumek et al, 2009). In addition, some studies also show that different insect food guilds respond differently to vegetation heterogeneity or third trophic level pressure (Grimbacher & Stork, 2007;Neves et al, 2013;Leal et al, 2015).…”

“…The sampled insects were properly conditioned in individual plastic containers and transported to the Laboratory of Conservation Biology where they were screened and identifi ed. The insects collected were identifi ed to family level using taxonomic keys and separated into morphospecies (see Leal et al, 2015). Then the herbivores were grouped into two guilds (sucking or chewing) according to their feeding habits (Neves et al, 2014).…”

“…Vegetation heterogeneity (i.e. richness and abundance of plants) is considered to be a good predictor of the local diversity of insect herbivores, especially in tropical terrestrial ecosystems (Araújo et al, 2013;Leal et al, 2015;Nascimento et al, 2015). In general, the number of insect species is directly related to local vegetation heterogeneity (Root, 1973;McCoy et al, 1991;Scherber et al, 2010;Lin et al, 2015), but the lack of a relation (Coelho et al, 2017) or a negative relation between these variables have also been documented (Neves et al, 2012).…”

Distribution of insect galls in xeric and mesic habitats of Floresta Nacional de Silvânia, Brazil

“…In this context, the Cerrado constitutes a mosaic of phytophysiognomies, with many mesic (i.e., non-sclerophyllic and rich in water and nutrients) and xeric (i.e., sclerophyllic and poor in water and nutrients) vegetation types. These environmental diff erences between xeric and mesic habitats can directly aff ect the distribution of insect herbivores (Neves et al, 2010;Leal et al, 2015), such as the highly specialized gall-inducing insects (Araújo et al, 2014).…”