Species turnover drives ß-diversity patterns across multiple spatial scales of plant-galling interactions in mountaintop grasslands.

This study describes differences in species richness and composition of the assemblages of galling insects and their host plants at different spatial scales. Sampling was conducted along altitudinal gradients composed of campos rupestres and campos de altitude of two mountain complexes in southeastern Brazil: Espinhaço Range and Mantiqueira Range. The following hypotheses were tested: i) local and regional richness of host plants and galling insects are positively correlated; ii) beta diversity is the most important component of regional diversity of host plants and galling insects; and iii) Turnover is the main mechanism driving beta diversity of both host plants and galling insects. Local richness of galling insects and host plants increased with increasing regional richness of species, suggesting a pattern of unsaturated communities. The additive partition of regional richness (γ) into local and beta components shows that local richnesses (α) of species of galling insects and host plants are low relative to regional richness; the beta (ß) component incorporates most of the regional richness. The multi-scale analysis of additive partitioning showed similar patterns for galling insects and host plants with the local component (α) incorporated a small part of regional richness. Beta diversity of galling insects and host plants were mainly the result of turnover, with little contribution from nesting. Although the species composition of galling insects and host plant species varied among sample sites, mountains and even mountain ranges, local richness remained relatively low. In this way, the addition of local habitats with different landscapes substantially affects regional richness. Each mountain contributes fundamentally to the composition of regional diversity of galling insects and host plants, and so the design of future conservation strategies should incorporate multiple scales.

Gall-inducing insects from Serra do Cabral, Minas Gerais, Brazil / Insetos indutores de galhas da Serra do Cabral, Minas Gerais, Brasil

Our goal was describe the gall richness through the characterization of their external shapes and occurrence patterns in their host plants from Parque Estadual da Serra do Cabral. In a universe of 34 families, 64 genera and 89 plant species, 47 gall-inducing insects in 21 families, 32 genera and 39 host plant species were recorded. The families, which hosted higher gall richness, were those with highest abundance. Asteraceae represented 33% of the species collected followed by Malpighiaceae 8% and Fabaceae 8%, each one concentrating 25%, 19% and 8% of gall-inducing insects, respectively. The organ most attacked was the leaf (51%), followed by the stem (42%) and the terminal branch (4%). Ninety-six percent (96%) of galls were glabrous. Only 25.5% of the galls described in our study have been already recorded in previous studies, reinforcing the need to increase the sampling effort toward a better understanding of the richness, distribution, and natural history of gall-inducing insects from Brazil.

Objetivo deste estudo foi descrever a riqueza de morfotipos de galha por meio da caracterização de suas formas e os padrões de ocorrência em suas plantas hospedeiras no Parque Estadual da Serra do Cabral. Num universo de 34 famílias, 64 gêneros e 89 espécies de plantas, foram registradas 47 espécies de galhas induzidas por insetos em 21 famílias, 32 gêneros e 39 espécies de plantas hospedeiras. As famílias que concentraram maior riqueza de insetos galhadores foram as famílias mais abundantes. A família Asteraceae representou 33% das espécies coletadas, seguida das Malpighiaceae 8% e Fabaceae 8%, cada uma concentrando 25%, 19% e 8% das espécies de insetos galhadores, respectivamente. O órgão mais atacado foi a folha (51%), seguido do caule (42%) e ramo terminal (4%). Noventa e seis por cento (96%) das galhas foram glabras. O fato de apenas 25% das galhas descritas neste estudo já terem sido registradas em trabalhos prévios, reforça a necessidade em aumentar o esforço amostral na direção de um maior conhecimento sobre a riqueza, distribuição e história natural dos insetos indutores de galhas no Brasil.