No abstract

1. Fire is one of the main factors shaping vegetation characteristics around the world, with deep and complex effects on higher levels of the food web and ecosystem functioning. Specialist insects tend to be more vulnerable to fire than generalists due to their higher dependency on host plants; however, fire effects on specialist insects are still not clearly known.2. Our aim was to understand how fire-induced changes in plant richness and floristic composition modulate community features of galling insects under different fire scenarios. Specifically, we address the following questions: Are changes in galling insect richness and herbivory explained by the variation in plant richness and floristic composition under different fire scenarios? Are species composition of vegetation and galling insect communities coupled under different fire scenarios? 3. Species richness of plant and galling insect communities was higher in burned than in unburned plots, but the highest species richness was observed under different fire scenarios in both communities. Galling insect richness was better predicted by floristic composition than plant richness. Herbivory was similar under different fire scenarios and weakly related to plant richness and composition. Species composition of vegetation and galling insect communities was strongly coupled across different fire scenarios.4. The characteristics of galling insect communities were strongly affected by fire through vegetation changes, and were better explained by floristic composition than by plant richness. Our results highlight the importance of selecting areas under different fire scenarios to maximise biodiversity conservation.

Baccharis spicata is a plant native to the south of South America And is infected by psyllids of the Baccharopelma genus, which induce a fold gall in its leaves. This infection induces a series of anatomical and phytochemical variations compared to the healthy leaf: the content of total phenolic compounds and total hidroxycinnamic derivatives is lower, though the chlorogenic acid measured by HPLC remains the same and the 4,5 dichlorogenic acid content is near the half of the one observed in the one in the healthy leaf. Regarding to its anatomy, the gall has an homogeneous mesophyll and flavonoids in its outer epidermis compared to an isobilateral mesophyll and epidermal flavonoidic idioblasts observed in the leaf. The increase in the expression of waxes suggests it is a protective function against the desiccation by preventing water evaporation in the structure. The results here exposed suggest that the psyllid manipulates plant tissues, inducing hyperplasia and hypertrophy in the tissues, differentiating them from healthy structures and inducing changes in the biosynthesis of secondary polyphenolic metabolites that act like intermediary between the gall and the environment.

Galls are structures produced by plants in response to the activity of several types of organisms. Gall-inducing species have a close relationship with their host plant, as their habitat is largely restricted to the gall and the plant organ in which it develops. All plant organs are susceptible to gall induction by insects, the leaves being the most vulnerable. Knowledge about interactions between gall-inducing insects and plants is fragmented and incomplete in Argentina. In this study, we completed an inventory of galls induced by insects on plants in Córdoba (central Argentina) using information from field surveys and a review of the literature. We also focused on the frequency of plant-insect taxonomic associations and plant organs most commonly attacked by gall-inducing insects. Field surveys were performed systematically in 26 sites of Chaco Serrano, which were visited five times in two consecutive years, and in17 sites of the province, which were sampled one or two times each. A comprehensive literature search of electronic and conventional databases was also conducted to complete the inventory. A total of 99 gall morphospecies on 58 plant species (21 families and 44 genera) were recorded through both field surveys and a literature review, enlarging the list of species available for the region by almost 50 %. Asteraceae and Fabaceae were the plant families most attacked by galling insects, in partial concordance with the most species-rich plant families in the region. Diptera, particularly the family Cecidomyiidae, was the most species-rich group in the community of galling insects, which is in agreement with different studies across the globe. Baccharis was the genus displaying the highest number of gall morphotypes, followed by Acacia, Condalia, Geoffroea, Prosopis and Schinus. Almost 60 % of the morphotypes were stem galls, a pattern uncommon in the literature. Fusiform and globoid-shaped galls were predominant. Our study highlights the scarce knowledge there is about the interactions between plants and gall-inducing insects in Argentina, particularly those involving species of Cecidomyiidae, with more than 30 undescribed species. Possible mechanisms involved in the predominance of stem galls in central Argentina are discussed.

Two new species of cecidomyiids were identified on Prosopis caldenia Burkart (Fabaceae) in Argentina: Rhopalomyia caldeniae Cornejo & Martínez sp. nov., as the inducer of bivalve leaf galls, and the inquiline Dasineura oportunista Cornejo & Martínez sp. nov. These galls are composed of the partial coalescence of two contiguous pinnulae that delimit a single larval chamber, where both species develop. Seven other species were reared from these galls as parasitoids and inquilines.

El Estornino Pinto (Sturnus vulgaris) es un ave introducida en Argentina que establece dormideros comunales durante la época no reproductiva. A pesar de ser una de las especies invasoras más perjudiciales del mundo, se conoce muy poco acerca de su ecología en Argentina. En este trabajo se caracterizaron los dormideros comunales del Estornino Pinto en la ciudad de La Plata con el objetivo de evaluar la selección del sitio de dormidero por parte de la especie. Se encontró un total de 34 dormideros, todos establecidos en especies de árbol perennifolias, siendo Phoenix canariensis la especie dominante (74%). El Estornino Pinto prefirió árboles con alta cobertura y sitios con un mayor número de individuos de Phoenix canariensis en el ambiente circundante. Los resultados de este trabajo apoyan la hipótesis de las ventajas microclimáticas en la formación de dormideros comunales y brindan información de utilidad para el manejo de esta especie en áreas urbanas de Argentina.