Questioning the environmental stress hypothesis for gall diversity of restinga vegetation on dunes

Abstract

Abstract:The Atlantic Coast Restinga is a mosaic of plant communities with a distinct floristic and phytophysiognomy, exposed to luminous, thermal, and saline stresses. Plants of the restinga must have special features commonly associated to xeric environments, and are expected to host a high diversity of galling herbivores. We studied gall morphotypes, and recorded the diversity of galls on plants growing in sand dunes in a remnant area of restinga (Acaraí State Park) in São Francisco do Sul, Santa Catarina State, Brazil. The sampling was done in four plots (250 x 5 m), constituting a total area of 5 000 m², during April, May and June. Plant branches (n ≥ 5) with galls were sampled, identified, and the galls were photographed. The galls were classified into eight morphotypes, associated to eight host plants constituting 15 host plants -galling herbivores systems. The identification of the gall -inducers was based on literature, and on the species-specific feature of this kind of host plant-gall inducers interaction. There was a predominance of leaf galls, green in color. The most common morphotypes were the globoid, lenticular, conical, rosette, marginal, and fusiform galls, similarly to the inventories performed on other Brazilian biomes. Despite the environmental stresses, the xeric features of the dunes of the ASP, and the high local plant diversity, the diversity of galling herbivores were low. Varronia curassavica (Boraginaceae), Smilax campestris (Smilacaceae), and Guapira opposita (Nyctaginaceae) were superhosts of galling herbivores in the dunes, with about 70 % of the total associated parasites. The environmental effect seems to be neutral, either for the host plants or for the generation of gall morphotypes. Alternatively, the scarce nutritional resources could be restrictive for the establishment of the galling herbivores inside plant tissues. Rev. Biol. Trop. 63 (4): 959-970. Epub 2015 December 01.

Insect galls from Córdoba, central Argentina: a case where stem galls predominate

“…Surprisingly, stems were the organs most frequently affected by galling insects in Cordoba. This result disagrees with the general trend of leaves being the preferred organ for galling insects (Mani, 1964;Shorthouse & Rohfritsch, 1992;Quintero et al, 2014;Arriola et al, 2015;Kuzmanich et al, 2015;Maia & Carvalho-Fernandes, 2016). Just a few studies have reported a greater number of galls on plant stems (Fernandes et al, 2002;Veldtman & McGeoch, 2003;Carneiro et al, 2009;Coelho et al, 2013;), and in some of these cases, they were restricted to a single insect taxon, such as Coleoptera (Maia & Oliveira, 2004).…”

“…The plant families hosting the highest number of galls were Asteraceae (27.2 % of interactions) and Fabaceae (22.2 %). Several studies conducted in the Neotropical region reported Asteraceae (Carneiro et al, 2009;Coelho et al, 2013;Arriola et al, 2015;Kuzmanich et al, 2015) and Fabaceae (Fernandes et al, 2002;Coelho et al, 2009;Carvalho-Fernandes, Silva De Almeida-Cortez, & Ferreira, 2012;Urso-Guimarães et al, 2017) as the families most frequently attacked by galling insects. In Córdoba, the families best represented in the vegetation are Poaceae, Asteraceae and Fabaceae, in that order (Zuloaga, Morrone, & Rodriguez, 1999;Giorgis et al, 2011); the predominance of the last two plant families in our records is partially concordant with the "plant family size hypothesis", which predicts a positive correlation between the high number of plant species and the number of associated gall morphotypes (Fernandes, 1992).…”

“…A few studies have reported stems as the most affected organs (Veldtman & McGeoch, 2003;Carneiro, Borges, Araújo, & Fernandes, 2009;Coelho, Carneiro, Branco, Borges, & Fernandes, 2013;Fernandes et al, 2002;Toma & Mendonça, 2013). The resultant galls have been classified according to their shapes, the organs they affect and other features, in a high number of morphological types (Isaias, Carneiro, Oliveira, & Santos, 2013;Arriola, Melo, & Isaias, 2015).…”

O vigor da planta altera a densidade de galhas em populações de Baccharis longiattenuata (Asteraceae) sob distintas condições de solo?

“…É sabido que em ambientes xéricos, ocorre uma alta diversidade e abundância de galhas (Fernandes & Price 1992;Price 1987), por isso, uma gama de estudos tem sido conduzida em vegetações sob condições xéricas, como cerrados, restingas e dosséis de florestas, com a finalidade de identificar as dinâmicas galhador-hospedeiro (Ribeiro & Basset 2007;Tuller et al 2013;Julião et al 2014;Arriola et al 2015;Arriola & Melo Jr. 2016;Silva et al 2016).…”

“…Em restinga, a maioria dos estudos sobre galhas consistem em levantamento e registro de espécies (Bregonci et al 2010;Maia 2013;Arriola et al 2015;Arriola & Melo Jr. 2016), sendo que poucos estudos avaliaram os fatores que afetam a dinâmica galha-hospedeiro. Em Dalbergia ecastophyllum (L.) Taubert.…”