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

Abstract

ABSTRACT. We investigated the insect gall distribution along savanna (xeric) and forest (mesic) vegetation in the Floresta Nacional de Silvânia, Goiás, Brazil. We tested if the insect gall diversity is higher in the xeric vegetation than in the mesic vegetation, as predicted by the hygrothermal stress hypothesis. The insect gall fauna was surveyed between December 2009 and June 2010 in two transects established each vegetation type. In total we found 186 insect gall morphotypes, distributed on 35 botanical families and 61 plant species. Cecidomyiidae (Diptera) induced the most insect galls (34.1%), and the plant family Fabaceae had the greatest richness of insect gall morphotypes (18). We recorded 99 insect gall morphotypes in the forest and 87 morphotypes in the savanna vegetation, being that none insect gall morphotype occurred in both habitats. We found that the insect gall richness and abundance did not diff er between forest and savanna transects. On the other hand, the estimated insect gall richness was higher in the forest than in the savanna. Our fi ndings contrary the hygrothermal stress hypothesis possibly because forest habitats have higher plant architecture complexity and occurrence of super-host taxa than the savanna habitats.KEYWORDS. Cecidomyiidae, Cerrado, Fabaceae, plant-insect interaction.RESUMO. Distribuição de galhas de insetos em habitats xéricos e mésicos da Floresta Nacional de Silvânia, Brasil. Foi inventariada a distribuição de galhas de insetos ao longo de vegetações savânicas (xéricas) e fl orestais (mésicas) na Floresta Nacional de Silvânia, Goiás, Brasil. O estudo testou se a diversidade de insetos galhadores é maior na vegetação xérica do que na vegetação mésica, como predito pela hipótese do estresse higrotermal. A fauna de galhadores foi amostrada entre dezembro de 2009 e junho de 2010 em dois transectos estabelecidos em cada tipo de vegetação. No total foram encontrados 186 morfotipos de galhas de insetos, distribuídos em 35 famílias e 61 espécies de plantas. Cecidomyiidae (Diptera) induziu a maioria das galhas de insetos (34,1%) e a família Fabaceae teve a maior riqueza de morfotipos de galhas (18). Foram registrados 99 morfotipos de galhas de insetos na fl oresta e 87 morfotipos no cerrado, sendo que nenhum morfotipo de galha ocorreu em ambos os habitats. A riqueza e a abundância de galhas de insetos não diferiram entre os transectos de fl oresta e cerrado. Por outro lado, a riqueza estimada de galhas de insetos foi maior na fl oresta do que no cerrado. Esses resultados contrariam a hipótese do estresse higrotermal possivelmente devido aos habitats fl orestais apresentarem maior complexidade arquitetônica das plantas e ocorrência de táxons super-hospedeiros do que os hábitats savânicos.PALAVRAS-CHAVE. Cecidomyiidae, Cerrado, Fabaceae, interação inseto-planta.

Effects of vegetation structure and edge proximity on insect distribution in an arboreal Caatinga area in Brazil

“…Vegetation structure is sometimes more determinant than abiotic or anthropic effects (Kemp & Ellis, 2017) because they affect different insect groups and trophic levels (Obermaier et al, 2008). In this sense, there is evidence that environments with more complex vegetation may have a greater diversity of insects (Borges & Brown, 2001;Diniz et al, 2010), mainly herbivores (Leal et al, 2016;Bergamini et al, 2017). It is because more complex environments have greater habitat heterogeneity and thus greater resource availability (Grez & Gonzalez, 1995).…”

Plant Architecture and Gall Abundance on Two Plant Species From Restinga, Rj, Brazil

“…Sessile and host-specific herbivores, such as gall-inducing insects, are usually patchily distributed within the populations of their host plants, and it has been suggested that both bottom-up and top-down effects explain variations in gall abundance (Araújo et al 2006, Barbosa & Fernandes 2014, distribution (Lara et al 2008;Bergamini et al 2017) and survivorship (Hosaka et al 2009). Given the specific features of insect-plant interactions, a number of hypotheses have been proposed to account for the patterns of distribution and abundance of gall morphotypes, and of insects that induce these galls on their respective plant hosts (Fleck & Fonseca 2007).…”

Accidental capture of the arboreal rodent Rhipidomys cf. macrurus in a mist-net in Silvânia National Forest, Brazil

“…The event was noticed on December 8th, at 8:30 pm during a routine inspection of a mist net installed in a fragment of semi-deciduous forest (16° 38' 25.29" S; 48° 38' 57.24" W) at the Silvânia National Forest Conservation Unit (FLONA-Silvânia), Silvânia, Goiás, Brazil. The Park has an area of 486.37 ha (MMA 2021), exhibiting almost all types of Cerrado vegetation, but mainly savannas and typical forests (Araújo et al 2012;Bergamini et al 2017). The rodent was removed from the mist-net, weighed (64 g), and released in the same capture area (Figure 1).…”