Soil-plant-gall relationships: from gall development to ecological patterns.

The adaptive nature of the galler habit has been tentatively explained by the nutrition, microenvironment, and enemy hypotheses. Soil attributes have direct relationships with these three hypotheses at the cellular and macroecological scales, but their influence has been restricted previously to effects on the nutritional status of the host plant on gall richness and abundance. Herein, we discuss the ionome patterns within gall tissues and their significance for gall development, physiology, structure, and for the nutrition of the gallers. Previous ecological and chemical quantification focused extensively on nitrogen and carbon contents, evoking the carbon-nutrient defence hypothesis as an explanation for establishing the plant-gall interaction. Different elements are involved in cell wall composition dynamics, antioxidant activity, and regulation of plant-gall water dynamics. An overview of the different soil-plant-gall relationships highlights the complexity of the nutritional requirements of gallers, which are strongly influenced by environmental soil traits. Soil and plant chemical profiles interact to determine the outcome of plant-herbivore interactions and need to be addressed by considering not only the soil features and galler nutrition but also the host plant's physiological traits. The quantitative and qualitative results for iron metabolism in gall tissues, as well as the roles of iron as an essential element in the physiology and reproduction of gallers suggest that it may represent a key nutritional resource, aligning with the nutrition hypothesis, and providing an integrative explanation for higher gall diversity in iron-rich soils.

Insect galls in Rupestrian field and Cerrado stricto sensu vegetation in Caetité, Bahia, Brazil / Galhas de insetos em vegetação de Campo Rupestre e de Cerrado stricto sensu de Caetité, Bahia, Brasil

Abstract: We investigated insect galls in Rupestrian field and Cerrado vegetation in the municipality of Caetité (BA), Brazil, between August/2015 and June/2016. This is the first study of gall diversity in Rupestrian field vegetation in that state. We encountered 48 different morphotypes of galls, distributed among 17 different plant species belonging to 13 genera and 21 host plant families. The greatest gall richness was observed in Cerrado (n=39) as compared to Rupestrian field (n=9) vegetation. The principal botanical families observed with galls were Leguminosae, Malpighiaceae, and Myrtaceae, with 10, 8 and 4 morphotypes, respectively. The genera showing the greatest gall diversity were Copaifera L. (n=6) (Leguminosae-Detarioideae), Croton L. (n=2) (Euphorbiaceae), Mimosa L. (n=2) (Leguminosae-Caesalpinioideae), Byrsonima Rich. ex Kunth (n=2) (Malpighiaceae), and Eugenia L. (n=2) (Myrtaceae). The super-host species was Copaifera sabulicola J.A.S. Costa & L.P. Queiroz (n= 5). Most galls occurred on leaves, being globoid, glabrous, isolated, and unilocular. Most gall-inducing insect species belong to the Cecidomyiidae family, while the associated fauna was represented by Hymenoptera and Lepidoptera. We recorded here for the first time galls on Ocotea velutina (Mart. ex Ness) Rohwer (Lauraceae) and Miconia alborufescens Naudin (Melastomataceae). The results indicate the need for more studies to understand the dynamics of the insect-induced galls in Rupestrian field.

Resumo: Este estudo investigou e caracterizou as galhas de uma área de Campo rupestre e de Cerrado no município de Caetité (BA) no período de agosto de 2015 a junho de 2016. Esta é a primeira contribuição para o conhecimento da diversidade de galhas de Campo rupestre neste estado. Foram registrados 48 morfotipos de galhas distribuídas em 17 espécies distintas, pertencentes a 13 gêneros e 21 famílias de plantas hospedeiras. A maior riqueza de galhas foi observada no Cerrado (n=39), quando comparada com o Campo rupestre (n=9). As famílias botânicas mais ricas em galhas foram Leguminosae, Malpighiaceae e Myrtaceae, com 10, 8 e 4 morfotipos, respectivamente. Os gêneros com maior diversidade de galhas foram Copaifera L. (n=6) (Leguminosae-Detarioideae), Croton L. (n=2) (Euphorbiaceae), Mimosa L. (n=2) (Leguminosae-Caesalpinioideae), Byrsonima Rich. ex Kunth (n=2) (Malpighiaceae) e Eugenia L. (n=2) (Myrtaceae). A espécie super-hospedeira foi Copaifera sabulicola J.A.S. Costa & L.P. Queiroz (n= 5). A maioria das galhas ocorreu nas folhas, sendo globoides, glabras, isoladas e uniloculares. A maioria dos indutores pertence à família Cecidomyiidae, enquanto que a fauna associada está representada por Hymenoptera e Lepidoptera. Foram registradas pela primeira vez galhas em Ocotea velutina (Mart. ex Ness) Rohwer (Lauraceae) e Miconia alborufescens Naudin (Melastomataceae). Os resultados encontrados indicam a necessidade de mais estudos para entender a dinâmica dos insetos indutores de galhas em Campos rupestres.

Insect galls from Serra Geral, Caetité, BA, Brazil / Galhas de insetos da Serra Geral, Caetité, Bahia, Brasil

We inventoried and characterized the kinds of gall, gall-inducing insects and host plants from Serra Geral between August 2013 and July 2014. Two phytophysiognomies, cerrado sensu stricto and caatinga-cerrado, were examined monthly along transects during ca. 4 hours per visit, totaling 48 hours of sampling effort. A total of 49 gall morphotypes were found on 14 species of host plants in 18 genera and 13 families. Fabaceae and Malpighiaceae were the families with the most galls, with 22 and 10 gall morphotypes, respectively. The genera of host plant with the greatest richness of galls were Copaifera L. (n=10), Bauhinia Benth. (n=6), and Mimosa L. (n=5). Galls were found on leaves, buds and stems. The majority of the galls were globoid, glabrous, isolated, and one-chambered. The inducers belong to Coleoptera, Diptera, and Lepidoptera, Cecidomyiidae (Diptera) being the most frequent and diverse gall-inducers. The associated fauna included parasitoids (Hymenoptera), successors (Formicidae), and predators (Pseudoscorpiones), obtained from 13, 2, and 1 gall morphotypes, respectively. Five plant taxa are recorded as hosts of gall-inducing insects for the first time.

Inventariamos e caracterizamos os tipos de galhas, insetos galhadores e plantas hospedeiras da Serra Geral entre agosto de 2013 a julho de 2014. Duas fitofisionomias, cerrado sensu stricto e de transição caatinga-cerrado, foram examinadas ao longo de trilhas è procura de galhas entomógenas, durante quatro horas por visita, totalizando 48 horas de esforço amostral. Um total de 49 morfotipos de galhas foi encontrado em 14 espécies vegetais pertencentes a 18 gêneros e 13 famílias. Fabaceae e Malpighiaceae foram as famílias botânicas com maior riqueza de galhas, com 22 e 10 morfotipos, respectivamente. Os gêneros de planta hospedeira mais ricos em galhas foram Copaifera L. (n=10), Bauhinia Benth. (n=6) e Mimosa L. (n=4). As galhas foram encontradas em folhas, gemas e caules. A maioria das galhas foram globoides, glabras, isoladas e uniloculares. Os galhadores pertencem ès ordens Coleoptera, Diptera e Lepidoptera, sendo os insetos da família Cecidomyiidae (Diptera) os indutores mais frequentes e diversificados. A fauna associada incluiu parasitoides (Hymenoptera), sucessores (Formicidae, Hymenoptera) e predadores (Pseudoscorpiones), obtidos de 13, dois e um morfotipos de galhas, respectivamente. Cinco táxons de plantas são registrados como hospedeiras de galhas pela primeira vez.