Gall-inducing Insects Research Articles

The Localization of Phytohormones within the Gall-inducing Insect Eurosta solidaginis (Diptera: Tephritidae).

The phytohormone production hypothesis suggests that organisms, including insects, induce galls by producing and secreting plant growth hormones. Auxins and cytokinins are classes of phytohormones that induce cell growth and cell division, which could contribute to the plant tissue proliferation which constitutes the covering gall. Bacteria, symbiotic with insects, may also play a part in gall induction by insects through the synthesis of phytohormones or other effectors. Past studies have shown that concentrations of cytokinins and auxins in gall-inducing insects are higher than in their host plants. However, these analyses have involved whole-body extractions. Using immunolocalization of cytokinin and auxin, in the gall inducing stage of Eurosta solidaginis, we found both phytohormones to localize almost exclusively to the salivary glands. Co-localization of phytohormone label with a nucleic acid stain in the salivary glands revealed the absence of Wolbachia sp., the bacterial symbiont of E. solidaginis, which suggests that phytohormone production is symbiont independent. Our findings are consistent with the hypothesis that phytohormones are synthesized in and secreted from the salivary glands of E. solidaginis into host-plant tissues for the purpose of manipulating the host plant.

Isolation, Identification, and Analysis of Potential Functions of Culturable Bacteria Associated with an Invasive Gall Wasp, Leptocybe invasa.

Symbioses between invasive insects and bacteria are one of the key drivers of insect invasion success. Gall-inducing insects stimulate host plants to produce galls, which affects the normal growth of plants. Leptocybe invasa Fisher et La Salle, an invasive gall-inducing wasp, mainly damages Eucalyptus plantations in Southern China, but little is known about its associated bacteria. The aim of this study was to assess the diversity of bacterial communities at different developmental stages of L. invasa and to identify possible ecological functions of the associated bacteria. Bacteria associated with L. invasa were isolated using culture-dependent methods and their taxonomic statuses were determined by sequencing the 16S rRNA gene. A total of 88 species belonging to four phyla, 27 families, and 44 genera were identified by phylogenetic analysis. The four phyla were Proteobacteria, Actinobacteria, Firmicutes, and Bacteroidetes, mainly from the genera Pantoea, Enterobacter, Pseudomonas, Bacillus, Acinetobacter, Curtobacterium, Sphingobium, Klebsiella, and Rhizobium. Among them, 72 species were isolated in the insect gall stage and 46 species were isolated from the adult stage. The most abundant bacterial species were γ-Proteobacteria. We found significant differences in total bacterial counts and community compositions at different developmental stages, and identified possible ecological roles of L. invasa-associated bacteria. This study is the first to systematically investigate the associated bacteria of L. invasa using culture-dependent methods, and provides a reference for other gall-inducing insects and associated bacteria.

Structural Characteristics and Content of Polyphenolic Compounds in Healthy Organs and Galls Induced by Allodiplosis crassa Kieff. and Jörg (Cecydomyiidae, Diptera) on Geoffroea decorticans (Hook. and Arn.) Burkart (Leguminosae)

Chañar (Geoffroea decorticans- Fabaceae) is a tree from South America that is normally infected with galls originated by insects. One of its parasites is Allodiplosis crassa (Cecidomyiidae, Diptera) which produces globular galls with sticky prolongations. Since this plant has medicinal uses in Argentina, its infestation could alter the quality of the plant drug. The surface of insect-induced galls usually contains defensive features such as trichomes, increased hardness and an increase in the content of polyphenolic compounds. The objective of this research is to assess the structural and histochemical features of the gall and to compare the content of polyphenolic metabolites in the gall, in the healthy leaf and in lignified stems of G. decorticans. The methanolic extract from the galls showed the highest amount of polyphenolic and proanthocyanidins and the lowest amount of hydroxycinnamic derivatives and flavonoids compared to the methanolic extract of the leaves. The photographs taken from the external surface of the gall showed that some prolongations have heads. The histochemical analysis showed that the prolongations have a high amount of proanthocyanidins and flavonoids; and that the heads are reactive to Sudan III. These phytochemical and histological characteristics may have a defensive role against harmful fungi and parasites that attack the larvae of the A. crassa. The results of this study show the presence of defensive features in an insect-induced gall of a medicinal plant with potential implications in the pharmacological activity of this species. This is the first report of a histochemical and phytochemical study in G. corticans galls.

Fine Morphology of Antennal and Ovipositor Sensory Structures of the Gall Chestnut Wasp, Dryocosmus kuriphilus.

Simple SummaryHymenoptera encompass a large group of insects with different habits, ranging from phytophagy to parasitic/predatory lifestyles. This is also true in the superfamily Cynipoidea, where phytophagy becomes highly specialized towards the exploitation of specific plant tissues (i.e., buds), leading to the induction of galls. In this paper, we investigated the organization of antennal and ovipositor sensory structures in the chestnut gall wasp, Dryocosmus kuriphilus. This insect became a major threat to chestnut production in Italy in the last 15 years. We investigated only females (this is a parthenogenetic species with thelytoky), and on the antennae we found several sensilla with the clear functional specialization to different groups of stimuli, with almost no overlapping among each sensilla. Similarly, specialization was also found on the ovipositor where groups of gustatory and mechanoreceptive sensilla were observed. This information represents an advancement in the knowledge of this pest, which may be useful to understand the biological role of plant derived chemical cues or to implement new control methods.Dryocosmus kuriphilus is a gall-inducing insect, which can cause significant damage on plants of the genus Castanea Mill., 1754. Antennae and ovipositor are the main sensory organs involved in the location of suitable oviposition sites. Antennal sensilla are involved in the host plant location, while ovipositor sensilla assess the suitability of the ovipositional bud. On both organs, diverse sensillar organs are present. Here, the distribution and ultrastructural organization of the sensilla were investigated by scanning and transmission electron microscopy. The antennae of D. kuriphilus are filiform and composed of 14 antennomeres, with the distal flagellomere bearing the highest number of sensilla. On the antennae, 6 sensilla types were found; sensilla chaetica, campaniformia, coeloconica-I, coeloconica-II, trichoidea and placoidea. The sensilla placoidea and trichoidea were the most abundant types. On the external walls of the ovipositor, gustatory and mechanoreceptive sensilla were observed. Internally, the egg channel hosted two additional sensory structures. The putative functional role of each sensilla in the context of insect’s ecology is discussed as well as the ovipositional mechanism used by this insect.

Plant diversity drives responses of gall-inducing insects to anthropization in Neotropical savannas

Human-induced habitat modification is among the main factors that threaten biodiversity on the planet. For highly specialized herbivorous insects, such as galling insects, anthropogenic disturbances that affect plants can have great effects on insects. In this sense, in the present study, we investigated the diversity of host plants and gall-inducing insects in anthropized and preserved remnants of Neotropical savannas in the Brazilian Cerrado. Sampling was performed in 30 plots (10 × 10 m) distributed in six study areas. Of these total, fifteen plots were in areas with anthropized vegetation and fifteen plots in areas with preserved vegetation. Overall, we recorded 67 species of gall-inducing insects and 39 species of host plants. We found that the diversity of both host plant species and gall-inducing insects differed significantly between areas, being higher in preserved plots than in anthropized plots. Our results revelated that changes in the species richness and composition of gall-inducing insects from preserved environments to anthropized environments were mediated by changes in the richness and composition of the plant species, respectively. Our study stands out as the first to demonstrate that plant diversity drives responses of gall-inducing insects to human disturbance in Neotropical savannas. Our findings indicate that the preservation of natural vegetation is important for the conservation of plant assemblages and their gall-inducing insects in urban environments.

Gall-inducing Insects and Plants: The Induction Conundrum

Galls induced by insects and mites (insects, hereafter) have been a subject of interest to insect ecologists because of the unusual habit of gall induction and for their tightly connected relationships. These specialist insects and mites have been explored to explain the nature of interactions between them and the plants by entomologists, ecologists and plant physiologists over the last two centuries. However, the questions why only certain insect taxa induce galls on specific species of plants and how galls are induced remain challenging. Whereas several efforts made across the world implicate plant-growth regulators (PGRs) in answering the question on how galls are induced, this article emphasizes the establishment of a metaplasied cell at the location where the tip of the chitinous mandible or ovipositor first hits in the plant. In the light of the differentiation of a metaplasied cell, the earliest plant response, it is but critical to evaluate the physiology of that cell and the ‘new’ physiological events triggered around it, heralding gall initiation. PGRs certainly play a role in gall growth, but only during later stages. This article does not answer the question on how galls are induced. However, it brings to light the gaps that need to be addressed in future in the backdrop of the efforts made over the years. Since we need to deal with the physiological changes that occur in a metaplasied cell and a few adjacent cells, the use of sophisticated optical equipment and pertinent software to achieve a structured and articulate explanation impresses as the way to go.

A compilation of host plants and their gall-inducing insects for the Caatinga Biome

Abstract: Caatinga is a seasonally dry tropical forest, one of the richest in plant species. Unfortunately, many groups of herbivorous insects associated with these plants are poorly known. This study aimed to investigate the diversity of gall-inducing insects (GII) and host plants (HP) in the Caatinga. For this, we compiled the information available in the literature of inventories on GII and their HP communities, and the described gall midge species. We found 100 species, 72 genera, and 32 families of HP hosting a total of 156 morphospecies of GII and 12 species of described cecidomyiids. Plant species with only one GII species represented 74% of hosts, but in super HP (i.e., HP with a high number of GII), despite the small number of HP species, there were many GII species. Fabaceae was also the most specious family, with 30% of HP species and 40% of GII. Furthermore, our results showed a low number of species of HP and GII for the Brazilian Caatinga, that we discussed this pattern with the following arguments, first, it is likely that the number of galling insect inventories for the Caatinga is under-sampled, second the Caatinga has a relatively smaller number of plant species when compared to other biomes, and finally, we argue that the Caatinga is a seasonally dry tropical forest where the deciduousness represents a relevant factor in the colonization and performance rates of GII.

Key Plant, Key Pests: Oak (Quercus spp.)

This series of Key Plant, Key Pests publications is designed for Florida gardeners, horticulturalists, and landscape professionals to help identify common pests associated with common Florida flora. This new 9-page publication provides information and general management recommendations for borers, caterpillars, insect-induced galls, twig girdlers, oak leaf blister, root and butt rot, Tubakia leaf spot, mistletoe, psocids, lace bugs, woolly aphids, powdery mildew, Spanish and ball moss, and lichens. Written by Juanita Popenoe, Caroline R. Warwick, Adam G. Dale, and Alfred Huo, and published by the UF/IFAS Environmental Horticulture Department.https://edis.ifas.ufl.edu/ep596

Hiking trails effects on the diversity of gall-inducing insects in high altitude ecosystem, St. Katherine Protectorate, Egypt

Wadi Telah in the St. Katherine region of the Sinai, Egypt, is a high mountainous habitat with an outstanding biodiversity. At the same time, it is a preferred tourist destination and hiking area. It order to find out whether hiking has a negative effect on the insect populations in the area, a survey was carried out for the spatial variation of the diversity of gall-inducing insects at different distances from the main hiking trail. A total of 42,317 specimens of six gall-inducing insect species was found, belonging to three orders. Both the species richness and the abundance of gall-inducing insects were significantly positively correlated with the distance from the trail. In most species, the proportion of galled plants was significantly positively correlated with the distance from the hiking trail. These results indicate that even the “soft” disturbance resulting from a hiking trail has negative environmental impacts.

Insect egg-induced physiological changes and transcriptional reprogramming leading to gall formation.

Gall-inducing insects and their hosts present some of the most intricate plant-herbivore interactions. Oviposition on the host is often the first cue of future herbivory and events at this early time point can affect later life stages. Many gallers are devastating plant pests, yet little information regarding the plant-insect molecular interplay exists, particularly following egg deposition. We studied the physiological and transcriptional responses of Eucalyptus following oviposition by the gall-inducing wasp, Leptocybe invasa, to explore potential mechanisms governing defence responses and gall development. RNA sequencing and microscopy were used to explore a susceptible Eucalyptus-L. invasa interaction. Infested and control material was compared over time (1-3, 7 and 90 days post oviposition) to examine the transcriptional and morphological changes. Oviposition induces accumulation of reactive oxygen species and phenolics which is reflected in the transcriptome analysis. Gene expression supports phytohormones and 10 transcription factor subfamilies as key regulators. The egg and oviposition fluid stimulate cell division resulting in gall development. Eucalyptus responses to oviposition are apparent within 24 hr. Putative defences include the oxidative burst and barrier reinforcement. However, egg and oviposition fluid stimuli may redirect these responses towards gall development.

Differential development times of galls induced by Leptocybe invasa (Hymenoptera: Eulophidae) reveal differences in susceptibility between two Eucalyptus clones.

The significance of morphological responses of hosts on susceptibility against gall-inducing insects is relatively unknown, especially in planted forests. Here, we investigate the temporal morphological responses (gall development) induced by the invasive gall wasp Leptocybe invasa and the subsequent insect development in two Eucalyptus clones. Our results identified a novel stage of gall development, not previously reported, termed here 'brownish ring'. In both hosts similar gall development stages were observed. Although L. invasa oviposited in both clones, comparison of external morphological traits of galls over time revealed a differential response in the number of galls between clones. Comparison of the developmental time of each gall and insect stage between clones suggests that plant defense mechanisms against L. invasa are activated shortly after oviposition by the wasp, yet before gall formation. Gall number is an important parameter that should be used to measure host susceptibility among Eucalyptus clones. To the best of our knowledge, this is the first study showing differential morphological responses induced by a galling insect, even before gall formation, revealing differences in susceptibility between different plant hosts. These findings provide insight into the use of early stages of gall formation by L. invasa to prevent invasion and establishment of this pest.

Up-regulation of phenylpropanoid biosynthesis system in peach species by peach aphids produces anthocyanins that protect the aphids against UVB and UVC radiation.

Conspicuous color is a common trait of foliar galls, but their relationship with gall-inducing insects is unknown. Red and green galls were taken from sunny or shady parts of peach species Prunus persica (L.) Batsch. f. rubro-plena Schneid with peach aphid Tuberocephalus momonis (Matsumura) infestation. We found that the loss of photosynthetic pigments was associated with the conspicuous coloration of green gall tissues. The concentrations of anthocyanins significantly increased following ultraviolet (UV) irradiation of green gall tissues, suggesting that accumulation of anthocyanins in red galls is related to ultraviolet B and C (UVB and UVC) radiation. The expression of structural genes related to the biosynthesis of chlorogenic acid and malic acid benzoate was increased in all gall tissues and negatively correlated with the expression profiles of certain genes associated with photosynthetic biosynthesis, indicating that the increased transcript levels of the phenylpropanoid pathway might cause loss of photosynthetic efficiency in the gall tissues. Transcriptome and quantitative reverse transcription PCR analyses revealed that MYB transcription factors that up-regulate the biosynthesis of anthocyanins in red gall tissues might be activated by both UVB and UVC exposure. Comet assays suggest that green and red gall tissues have similar DNA damage following UV irradiation. No obvious effect of the up-regulated compounds on the growth of the peach aphid was observed. Interestingly, peach aphids under leaves painted with anthocyanins had lower mortality following UV irradiation than those in controls. These results suggest that the anthocyanins in red gall tissues have a defensive function for the peach aphid, protecting it against UV radiation.

Plant‐Galling Insect Interactions: A Data Set of Host Plants and Their Gall‐Inducing Insects for the Cerrado

Here, we present an open-access database of 968 records of interactions between gall-inducing insects and their host plants for the Brazilian Cerrado, one of the biomes with the highest galling insect diversity on Earth. The data set comprises 505 species of 222 genera and 67 families of host plants, and 48 species of Cecidomyiidae and one species of Tephritidae. Our study reveals knowledge gaps and encourages the execution of new cecidologic inventories in the Cerrado and other locations around the world. Our data set also provides base data for ecological and biogeographic studies. These photographs illustrate the article “Plant-galling insect interactions: a data set of host plants and their gall-inducing insects for the Cerrado” by Fernanda C. F. Cintra, Walter S. de Araújo, Valéria C. Maia, Maria V. Urso-Guimarães, Henrique Venâncio, Janete F. Andrade, Marco A. A. Carneiro, Wanessa R. de Almeida, and Jean C. Santos published in Ecology. https://doi.org/10.1002/ecy.3149.

Plant-galling insect interactions: a data set of host plants and their gall-inducing insects for the Cerrado.

Recent decades have seen increased research interest in the processes and mechanisms related to insect gall richness and host plants. The data set provided here includes 968 records of interactions between galling insects and host plants for the Cerrado biome. The data set comprises 505 species of 222 genera and 67 families of host plants. The botanical families most represented in the data set are Asteraceae, Fabaceae, Myrtaceae, Malpighiaceae, and Melastomataceae, which account for ~48.5% of all records and 52% of the total number of species. The gall-inducing insects listed in the data set include 48 species of Cecidomyiidae and one species of Tephritidae. This data set is the first to compile inventories of plant-galling insect communities and information about the diversity and distribution of insect galls and their host plants in the Cerrado. The data set reveals knowledge gaps and opportunities for future research on patterns of diversity and distribution, and provides a basis for generating and testing new ecological hypotheses. Please cite this data paper when using the current data in publications and let us know how the data are used in the publications. There are no copyright restrictions.

Gall-Inducing Parasites: Convergent and Conserved Strategies of Plant Manipulation by Insects and Nematodes.

Gall-inducing insects and nematodes engage in sophisticated interactions with their host plants. These parasites can induce major morphological and physiological changes in host roots, leaves, and other tissues. Sedentary endoparasitic nematodes, root-knot and cyst nematodes in particular, as well as gall-inducing and leaf-mining insects, manipulate plant development to form unique organs that provide them with food from feeding cells. Sometimes, infected tissues may undergo a developmental switch resulting in the formation of aberrant and spectacular structures (clubs or galls). We describe here the complex interactions between these plant-reprogramming sedentary endoparasites and their infected hosts, focusing on similarities between strategies of plant manipulation. We highlight progress in our understanding of the host plant response to infection and focus on the nematode and insect molecules secreted in planta. We suggest thatlooking at similarities may identify convergent and conserved strategies and shed light on the promise they hold for the development of new management strategies in agriculture and forestry.

Insect galls and their host plants in gallery forest in Bahia State, Brazil

Inventories of insect galls in gallery forests in Northeastern Brazil have been quite infrequent, and the richness of gall-inducing insects in that vegetation type has been little unknown. To contribute to our knowledge of galls, galling insects, and their host plants from gallery forest habitats in Northeastern Brazil, we documented and characterized the macroscopic aspects of the galls, identified the plant hosts and their endemism level and surveyed the associated fauna in an area of gallery forest in Caetite, Bahia State. We found 30 different gall morphotypes on 20 host plant species belonging to 17 genera and 13 families. The main host families of galls were Leguminosae and Myrtaceae with ten and four morphotypes, respectively. Most galls occurred on leaves and were globoid, green, glabrous, and grouped. Most of the gall-inducing insect species found belonged to Diptera (Cecidomyiidae) and Coleoptera, while the associated fauna was represented by Hemiptera, Hymenoptera, Collembola, and Thysanoptera. We recorded galls the first time on six plant species. These results reinforce the importance of gall inventories in gallery forest areas not yet examined to better understand gall richness, galling insects, and their host plants in that vegetation type.

Diversity of Gall-Inducing Insects Associated With a Widely Distributed Tropical Tree Species: Testing the Environmental Stress Hypothesis.

Abiotic factors can affect plant performance and cause stress, which in turn affects plant-herbivore interactions. The Environmental Stress Hypothesis (ESH) predicts that gall-inducing insect diversity will be greater on host plants that grow in stressful habitats. We tested this hypothesis, considering both historical and ecological scales, using the plant Copaifera langsdorffii Desf. (Fabaceae) as a model because it has a wide geographic distribution and is a super-host of gall-inducing insects. According to the ESH, we predicted that 1) on a historical scale, the diversity of gall-inducing insects will be higher in habitats with greater environmental stress and 2) on an ecological scale, gall-inducing insect diversity will be greater on plants that possess greater levels of foliar sclerophylly. We sampled gall-inducing insects on plants of C. langsdorffii in five sites with different levels of water and soil nutrient availability and separated from each other by a distance of up to 470 km. The composition, richness, and abundance of gall-inducing insects varied among study sites. Plants located in more stressful habitats had higher levels of foliar sclerophylly; but richness and abundance of gall-inducing insects were not affected by host plant sclerophylly. Habitat stress was a good predictor of gall-inducing insect diversity on a regional scale, thus corroborating the first prediction of the ESH. No relationship was found between plant sclerophylly and gall-inducing insect diversity within habitats. Therefore, on a local scale, we did not find support for our second prediction related to the ESH.

Reprogramming of the Developmental Program of Rhus javanica During Initial Stage of Gall Induction by Schlechtendalia chinensis.

Insect galls are unique organs that provide shelter and nutrients to the gall-inducing insects. Although insect galls are fascinating structures for their unique shapes and functions, the process by which gall-inducing insects induce such complex structures is not well understood. Here, we performed RNA-sequencing-based comparative transcriptomic analysis of the early developmental stage of horned gall to elucidate the early gall-inducing process carried out by the aphid, Schlechtendalia chinensis, in the Chinese sumac, Rhus javanica. There was no clear similarity in the global gene expression profiles between the gall tissue and other tissues, and the expression profiles of various biological categories such as phytohormone metabolism and signaling, stress-response pathways, secondary metabolic pathways, photosynthetic reaction, and floral organ development were dramatically altered. Particularly, master transcription factors that regulate meristem, flower, and fruit development, and biotic and abiotic stress-responsive genes were highly upregulated, whereas the expression of genes related to photosynthesis strongly decreased in the early stage of the gall development. In addition, we found that the expression of class-1 KNOX genes, whose ectopic overexpression is known to lead to the formation of de novo meristematic structures in leaf, was increased in the early development stage of gall tissue. These results strengthen the hypothesis that gall-inducing insects convert source tissues into fruit-like sink tissues by regulating the gene expression of host plants and demonstrate that such manipulation begins from the initial process of gall induction.

The History of Herbivory on Sphenophytes: A New Calamitalean with an Insect Gall from the Upper Pennsylvanian of Portugal and a Review of Arthropod Herbivory on an Ancient Lineage

Premise of research. Sphenophytes are a modestly diverse lineage of vascular plants with a persistent record extending from the late Paleozoic to the present. However, patterns of arthropod herbivory on sphenophytes are poorly known because of a scattered literature, which we address in this report.Methodology. We document the 315-million-year-long record of sphenophyte-arthropod herbivory by focusing on the bookends of that record—namely, the Pennsylvanian and the present day. We add to this milieu a gall association on a newly described sphenophyte from the Upper Pennsylvanian of Portugal.Pivotal results. Earliest-known sphenophyte herbivory is Early Pennsylvanian, when virtually all interactions involved piercing-and-sucking damage by stylate insect mouthparts and lesions from cutting-and-slicing ovipositors. An exception is a newly discovered calamitalean (Annularia paisii sp. nov.) that harbored a newly discovered insect-induced gall (Paleogallus carpannularites ichnosp. nov.) that is similar to a modern fern gall. This discovery suggests that Late Pennsylvanian interactions were more diverse than previously suspected. By the end of the Pennsylvanian, the component community of one whole-plant calamitalean species had 12 damage types (DTs), only one of which was nonpuncturing damage. Shifts to external foliage feeding, mining, and galling are evident during the Late Triassic. A Middle Jurassic renewal of interactions was followed by a decrease in documented DTs present in the Cretaceous and Cenozoic. Fifteen modern species of the genus Equisetum, the sole surviving sphenophyte lineage, exhibit four herbivory patterns. First, almost all documented herbivory is confined to the seven species of Equisetum (horsetails), not subgenus Hippochaete (scouring rushes). Second, there are diversification events of four genera of herbivores—a beetle, two sawflies, and a fly—on subgenus Equisetum. Third, this arthropod herbivory is approximately evenly split among monophagy, oligophagy, and polyphagy. Fourth, the herbivore component community of Equisetum arvense L. (field horsetail) is diverse, representing 10 major feeding modes, comparable to a modern angiosperm species; there are considerably more feeding modes for E. arvense than there are for Pennsylvanian calamitaleans.Conclusions. Pennsylvanian sphenophytes supported few folivores, and there was a major shift in the modes of sphenophyte herbivory after the Paleozoic. Considerable modern herbivory is localized on E. arvense.

Diversity of gall-inducing insect associated with a superhost plant species: Plant architecture, resource availability and interspecific interactions

Abstract. Fagundes M, Santos EML, Duarte KLR, Santos LM, Vieira JS, Oliveira CHD, Silva PS. 2020. Diversity of gall-inducing insect associated with a superhost plant species: Plant architecture, resource availability and interspecific interactions. Biodiversitas 21: 1182-1189. The role of interspecific competition in the organization of herbivorous insect communities may vary depending on resource availability. Trees are structurally more complex and have greater resource availability for herbivorous insects than shrubs. In this study, we evaluated the roles of plant architecture and interspecific interactions on community organization of the gall-inducing insect associated with trees (adult plants) and shrubs (young plants) of Copaifera langsdorffii. Our results showed that the species composition of gall-inducing insect communities associated with C. langsdorffii differed statistically between trees and shrubs. In addition, the trees presented greater diversity of gall-inducing insects than the shrubs, corroborating the hypothesis of plant architecture. The results of the analysis of null models showed that the co-occurrence of gall-inducing insect species associated with trees not differ from the co-occurrence predicted by chance. Thus, interspecific interactions cannot be used to explain the community organization of the gall-inducing insects on C. langsdorffii trees. On the other hand, the co-occurrence of gall-inducing insect species differed from the co-occurrence predicted by chance when shrubs plants were analyzed, indicating that biotic interactions can shape the structure of the gall-inducing insect community on shrubs. The lower availability of oviposition sites probably generates a dispute for these resources among females of different species of gall-inducing insects only in the shrubs. Therefore, the role of competition in the organization of herbivore insect communities on their host plant may vary depending on the ontogenetic stage of the host plant.