Cynipidae Research Articles

The effects of a parasitoid wasp of a gall-making insect on host plant characteristics and the abundance of sharing host-plant herbivore

Abstract. Triyogo A, Yasuda H. 2019. The effects of a parasitoid wasp of a gall-making insect on host plant characteristics and the abundance of sharing host-plant herbivore. Biodiversitas 20: 3499-3507. The present study has evaluated the indirect, top-down effects of a parasitoid wasp, Torymus beneficus Yasumatsu et Kamijo (Hymenoptera: Torymidae), of a gall-maker, Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae), on the characteristics of the chestnut tree, Castanea crenata Siebold & Zucc. (Fagales: Fagaceae), and the implications for other herbivores, the aphid, Myzocallis kuricola (Matsumura) (Homoptera: Aphididae). sharing the same host plant. In a field experiment, the behavior of D. kuriphilus larvae on chestnut tree was influenced by the T. beneficus as indicated by a small increment of gall volume. However, parasitism did not affect certain other leaf characteristics that were induced by the gall wasp. Here we show that the characteristics of chestnut tree induced by the gall-making wasp affected M. kuricola that subsequently attacked the chestnut tree. However, the hypothesis that top-down effects by natural enemies may affect other herbivores on chestnut tree through its influence on gall-making wasp was not supported in this study. This study shows that parasitism of a gall-maker does not affect the other herbivore sharing the same host plant. Furthermore, the top-down effects of the parasitoid's behavior on plants may have different effects on sharing host herbivores that attack galled plants.

The Asian Chestnut Gall Wasp in Italy: Surveys on its Native and Exotic Parasitoids as Well as on Chestnut Cultivar Susceptibility

In the context of biological control against the Asian chestnut gall wasp Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae) in Italy, the aim of this study was to survey its native parasitoids as well as the exotic Torymus sinensis Kamijo which had been introduced and released as a biological control agent. Furthermore, both parasitism and pest susceptibility of local chestnut trees were investigated. Surveys were carried out in 2014 in the Municipality of Sambuca Pistoiese (Pistoia), in a chestnut forest which included three cultivars: Nerattino, Carpinese, and Pastinese. On a total of 35 trees, selected among the three cultivars, 24 current-year shoots were randomly collected and examined in the laboratory. After the damage by the cynipid had been assessed, leaf samples were used for molecular analyses. Galls were also collected on the 35 selected trees both for dissection and to rear parasitoid specimens in the laboratory. The three cultivars were confirmed by genetic tests. The Carpinese cultivar resulted to be the most damaged, with highest percentage of attacked shoots (84.38%). Moreover it was also the cultivar with the lower parasitism rate (about 16%). From reared galls seven parasitoid species emerged, all belonging to the superfamily of Chalcidoidea. Exception made for the non-native T. sinensis, the other six were native species associated to oak gall wasps. Native parasitoids were more scarcely present, while the exotic T. sinensis amounted for the 84.27% of all emerged parasitoids. Our results confirm how chestnut susceptibility to D. kuriphilus varies depending on the cultivar. Overall, the Nerattino cultivar resulted as the best among the three examined: it was subject to a less intense attack than the other cultivars, and the resulting smaller galls were more effectively exploited by parasitoids.

Gall-Colonizing Ants and Their Role as Plant Defenders: From 'Bad Job' to 'Useful Service'.

Galls are neoformed structures on host plant tissues caused by the attack of insects or other organisms. They support different communities of specialized parasitic insects (the gall inducers), and can also provide refuge to other insects, such as moths, beetles and ants, referred to as secondary occupants. This study focuses on galls induced by the oak gall wasp Andricus quercustozae and secondarily colonized by ants in a mixed oak forest. A field survey and two experiments were carried out to a) study ant (species-specific) preferences for different features of the galls, b) describe differences in gall architecture due to ant activity, c) analyse the effects of the presence of gall-dwelling ants on plant health. The results show that there are differences between ant species in gall colonization and in the alteration of gall opening and inner structure. We verified that gall-dwelling ants protect their host plants efficiently, offering them an indirect defence mechanism against enemies (predators and pathogens). The data suggest a new paradigm in ant–plant relationships mediated by the presence of galls on the plants whose ecological and evolutionary implications are discussed.

The mechanism of plant gall induction by insects: revealing clues, facts, and consequences in a cross-kingdom complex interaction

Galls are defined as modifications of the normal developmental design of plants, produced by a specific reaction to the presence and activity of a foreign organism. Although different organisms have the ability to induce galls in plants, insect-induced galls are the most elaborate and diverse. Some hypotheses have been proposed to explain the induction mechanism of plant galls by insects. The most general hypothesis suggests that gall formation is triggered by the action of chemical substances secreted by the gall inducer, including plant growth regulators such as auxins, cytokinins, indole-3-acetic acid (IAA), and other types of compounds. However, the mode of action of these chemical substances and the general mechanism by which the insect could control and manipulate plant development and physiology is still not known. Moreover, resulting from the complexity of the induction process and development of insect galls, the chemical hypothesis is very unlikely a complete explanation of the mechanism of induction and morphogenesis of these structures. Previous and new highlights of insect gall systems with emphasis on the induction process were analyzed on the basis of the author’s integrated point of view to propose a different perspective of gall induction, which is provided in this article. Due to the extraordinary diversity of shapes, colors, and complex structures present in insect galls, they are useful models for studying how form and structure are determined at the molecular level in plant systems. Furthermore, plant galls constitute an important source of material for the study and exploration of new chemical substances of interest to humans, due to their physiological and adaptive characteristics. Considering the finely tuned control of morphogenesis, structural complexity, and biochemical regulation of plant galls induced by insects, it is proposed that an induction mechanism mediated by the insertion of exogenous genetic elements into the genome of plant gall cells could be involved in the formation of this kind of structure through an endosymbiotic bacterium.

Genomic dissection of an extended phenotype: Oak galling by a cynipid gall wasp.

Galls are plant tissues whose development is induced by another organism for the inducer's benefit. 30,000 arthropod species induce galls, and in most cases the inducing effectors and target plant systems are unknown. Cynipid gall wasps are a speciose monophyletic radiation that induce structurally complex galls on oaks and other plants. We used a model system comprising the gall wasp Biorhiza pallida and the oak Quercus robur to characterise inducer and host plant gene expression at defined stages through the development of galled and ungalled plant tissues, and tested alternative hypotheses for the origin and type of galling effectors and plant metabolic pathways involved. Oak gene expression patterns diverged markedly during development of galled and normal buds. Young galls showed elevated expression of oak genes similar to legume root nodule Nod factor-induced early nodulin (ENOD) genes and developmental parallels with oak buds. In contrast, mature galls showed substantially different patterns of gene expression to mature leaves. While most oak transcripts could be functionally annotated, many gall wasp transcripts of interest were novel. We found no evidence in the gall wasp for involvement of third-party symbionts in gall induction, for effector delivery using virus-like-particles, or for gallwasp expression of genes coding for plant hormones. Many differentially and highly expressed genes in young larvae encoded secretory peptides, which we hypothesise are effector proteins exported to plant tissues. Specifically, we propose that host arabinogalactan proteins and gall wasp chitinases interact in young galls to generate a somatic embryogenesis-like process in oak tissues surrounding the gall wasp larvae. Gall wasp larvae also expressed genes encoding multiple plant cell wall degrading enzymes (PCWDEs). These have functional orthologues in other gall inducing cynipids but not in figitid parasitoid sister groups, suggesting that they may be evolutionary innovations associated with cynipid gall induction.

Comparative transcriptome analysis of galls from four different host plants suggests the molecular mechanism of gall development.

Galls are plant structures generated by gall–inducing organisms including insects, nematodes, fungi, bacteria and viruses. Those made by insects generally consist of inner callus–like cells surrounded by lignified hard cells, supplying both nutrients and protection to the gall insects living inside. This indicates that gall insects hijack developmental processes in host plants to generate tissues for their own use. Although galls are morphologically diverse, the molecular mechanism for their development remains poorly understood. To identify genes involved in gall development, we performed RNA–sequencing based transcriptome analysis for leaf galls. We examined the young and mature galls of Glochidion obovatum (Phyllanthaceae), induced by the micromoth Caloptilia cecidophora (Lepidoptera: Gracillariidae), the leaf gall from Eurya japonica (Pentaphylacaceae) induced by Borboryctis euryae (Lepidoptera: Gracillariidae), and the strawberry-shaped leaf gall from Artemisia montana (Asteraceae) induced by gall midge Rhopalomyia yomogicola (Oligotrophini: Cecidomyiidae). Gene ontology (GO) analyses suggested that genes related to developmental processes are up–regulated, whereas ones related to photosynthesis are down–regulated in these three galls. Comparison of transcripts in these three galls together with the gall on leaves of Rhus javanica (Anacardiaceae), induced by the aphid Schlechtendalia chinensis (Hemiptera: Aphidoidea), suggested 38 genes commonly up–regulated in galls from different plant species. GO analysis showed that peptide biosynthesis and metabolism are commonly involved in the four different galls. Our results suggest that gall development involves common processes across gall inducers and plant taxa, providing an initial step towards understanding how they manipulate host plant developmental systems.

Galling insects as phenotype manipulators of cell wall composition during the development of galls induced on leaves of Aspidosperma tomentosum (Apocynaceae)

The gall structure is built from redifferentiation of host plant tissues, changing the cell wall proprieties and associated functions. Because of the oxidative stress imposed by the galling insect on the plant tissues, some phenotypic traits associated with cell wall metabolism may be suppressed during gall development. Using an immunocytochemical approach we investigated the pectin and glycoprotein composition of the cell walls during non-galled leaf development and galls induced on Aspidosperma tomentosum (Apocynaceae). Embedding in historesin was used for anatomical characterization, as well as for immunocytochemical analyses. The samples were probed with the primary monoclonal antibodies JIM5, JIM7, LM1, LM2, LM5 and LM6. The gall develops especially from cell hypertrophy and hyperplasia of the spongy and palisade parenchyma, which determine its shape. Epitopes of β-D-galactan and α-L-arabinan in the galls were totally suppressed or less expressed. The increased labeling of homogalacturonan epitopes, especially in senescent galls, is a clear indicator that pectin methylesterase activity is maintained despite oxidative stresses imposed by the galling insect. Arabinogalactan proteins were not detected in any non-galled leaf or gall stages. The galling insect deeply changed the structure and deposition pattern of the cell wall, promoting new functionalities in the gall tissue compartments.

Moisture stimulates galler emergence from dry season dormancy in the leaf litter

In tropical regions, a great proportion of trees and shrubs shed their leaves over the dry season. Since gall-inducing insects are generally host species-specific, where do they go when their hosts have no leaves? There is practically no research into dormancy strategies of tropical galling insects. We hypothesised that the galling insect Eurytoma sp. (Chalcidoidea, Eurytomidae) undergo dormancy inside their galls on shed leaves of the host plant Caryocar brasiliense Camb. (Caryocaraceae). The insects would emerge from the galls in synchrony with the sprouting of new leaves, at the beginning of the wet season, stimulated by increased moisture after the first rain of the wet season. In order to test that, we collected leaves from the leaf litter in the last month of the dry season and gently showered half of them in a sink to simulate rain. In the two weeks before the first rainfall, the watered leaves presented an over trifold higher gall eclosion rate than the ones in the control group. There is no previous account of a tropical galling insect undergoing dormancy inside galls in the leaf litter. We contrast this evidence with the possibility that, at least in the tropics, galls may also have had an adaptive value as dormancy structures during their evolutionary history, and evolved in response to the deciduousness of plants growing in harsh environments.

Rise and Fall of an Oak Gall Wasp (Hymenoptera: Cynipidae) Outbreak in Massachusetts.

The recently described oak gall wasp Zapatella davisae Buffington & Melika (Hymenoptera: Cynipidae) has caused extensive damage and mortality to black oak trees, Quercus velutina L. (Fagales: Fagaceae), in coastal parts of New England, United States. Like many newly described and/or newly introduced species, it is unclear how long populations of Z. davisae have existed in this region. However, as this species forms galls on the woody-tissue of its host, it may be possible to obtain historical information about changes in its population size by examining the presence of galls in relation to annual growth nodes. Here, we explore the utility of this approach to determine population size changes in Z. davisae densities on Nantucket, Martha's Vineyard, and Cape Cod, Massachusetts, through dissection of black oak branches. In addition, we calculated parasitism rates during the years of study and obtained morphological and molecular identifications for the parasitoids associated with Z. davisae. Our results show significant changes in population sizes, with higher levels of parasitism at sites on Martha's Vineyard and Cape Cod compared to sites on Nantucket. In addition, morphological examinations, in combination with DNA sequencing, identified the associated parasitoids as five species in the genus Sycophila Walker (Hymenoptera: Eurytomidae). We comment that considerable morphological variation within several of these recovered species was observed, present the first record of males for a species from which only females have been described, and suggest that future work is required to clarify the species boundaries for this important parasitoid group.

Fungal community associated with adults of the chestnut gall wasp Dryocosmus kuriphilus after emergence from galls: Taxonomy and functional ecology

The diversity of the fungal community associated with adults of Dryocosmus kuriphilus following emergence was examined using HTS analysis. Ascomycota dominated the fungal core-biome community. The functional guilds of the 90 taxa forming the core-biome were assessed, demonstrating three main groups: saprotrophs, plant pathogens and entomopathogens. Twenty-nine OTUs out of 90 were resolved to species level identifying 26 different fungal species. Among these species, many were cosmopolitan or previously recorded in Europe. Ten taxa were previously recorded on chestnut, including some recognized plant pathogens associated with foliage and green tissues such as Epicoccum nigrum, Gnomoniopsis castanea, Colletotrichum acutatum, Stromatoseptoria castaneicola, Ramularia endophylla. Beauveria bassiana; within the core microbiome, Fusarium larvarum represented the most abundant entomopathogenic species. Some of these species are known to impact directly or indirectly the vitality of the insects in the galls. The chestnut blight pathogen, Cryphonectria parasitica, was never found associated with D. kuriphilus. Based on the present study, an active role for D. kuriphilus as a vector of chestnut fungal endophyte/pathogens cannot be demonstrated but neither ruled out.

Fungal endophyte communities differ between chestnut galls and surrounding foliar tissues

Abstract Foliar endophytic fungi are present in almost all vascular plants. The composition of endophyte communities varies among plant individuals. Likely, but understudied, sources of this variation are the species composition of the plant community and initial attacks by insect herbivores. We addressed these issues by characterizing fungal endophyte communities on leaves of chestnut (Castanea sativa) grown in pure vs. mixed stands. We used ITS metabarcoding methods to identify endophytic fungi associated with galls caused by the invasive gall wasp, Dryocosmus kuriphilus, and with surrounding chestnut leaf tissues. We found 1378 different OTUs. The richness, diversity and composition of endophyte communities differed between galls and surrounding leaf tissues but were independent of forest stand composition. Fungal endophyte richness was lower in galls than in surrounding leaf tissues. Most differences in the composition of fungal endophyte communities between galls and foliar tissues were due to OTU turnover. These results suggest that insect-induced galls provide a particular habitat condition for endophytic microorganisms, regardless of forest species composition. A better understanding of endophyte biology is important to improve their use as biocontrol agents of galling insects.

DNA barcodes reveal inconsistent species boundaries in Diplolepis rose gall wasps and their Periclistus inquilines (Hymenoptera: Cynipidae)

AbstractRose gall wasps, Diplolepis Geoffroy (Hymenoptera: Cynipidae), induce structurally distinct galls on wild roses (Rosa Linnaeus; Rosaceae), which provide gallers with food and shelter. These galls are attacked by a wide variety of micro-hymenopterans, including Periclistus Förster (Hymenoptera: Cynipidae), which act as inquilines. Both Diplolepis and Periclistus are difficult to distinguish based on adult morphology, instead the structural appearance of galls is often used to distinguish species. Using the mitochondrial gene cytochrome c oxidase subunit I, we tested the species boundaries and built phylogenies of both Diplolepis and Periclistus. The molecular results have largely supported the validity of species described in the literature, with notable exceptions in four species groups. Periclistus exhibits a divide between the Palaearctic and Nearctic clades, and ranges from specialists to generalists in terms of host specificity. While it is premature to enact any taxonomic changes without additional molecular markers, this incongruence between morphological and molecular data indicates these groups need taxonomic revision and gall morphology alone may be inadequate to delimit species.

A keeper of many crypts: a behaviour-manipulating parasite attacks a taxonomically diverse array of oak gall wasp species

Parasites of animals and plants can encounter trade-offs between their specificity to any single host and their fitness on alternative hosts. For parasites that manipulate their host's behaviour, the added complexity of that manipulation may further limit the parasite's host range. However, this is rarely tested. The recently described crypt-keeper wasp, Euderus set, changes the behaviour of the gall wasp Bassettia pallida such that B. pallida chews a significantly smaller exit hole in the side of its larval chamber and 'plugs' that hole with its head before dying. Euderus set benefits from this head plug, as it facilitates the escape of the parasitoid from the crypt after it completes development. Here, we find direct and indirect evidence that E. set attacks and manipulates the behaviour of at least six additional gall wasp species, and that these hosts are taxonomically diverse. Interestingly, each of E. set's hosts has converged upon similarities in their extended phenotypes: the galls they induce on oaks share characters that may make them vulnerable to attack by E. set. The specialization required to behaviourally manipulate hosts may be less important in determining the range of hosts in this parasitoid system than other dimensions of the host-parasitoid interaction, like the host's physical defences.

Transcriptome characterization and expression profiling in chestnut cultivars resistant or susceptible to the gall wasp Dryocosmus kuriphilus.

The oriental gall wasp Dryocosmus kuriphilus represents a limiting pest for the European Chestnut (Castanea sativa, Fagaceae) as it creates severe yield losses. The European Chestnut is a deciduous tree, having major social, economic and environmental importance in Southern Europe, covering an area of 2.53 million hectares, including 75,000ha devoted to fruit production. Cultivars show different susceptibility and very few are resistant to gall wasp. To deeply investigate the plant response and understand which factors can lead the plant to develop or not the gall, the study of transcriptome is basic (fundamental). To date, little transcriptomic information are available for C. sativa species. Hence, we present a de novo assembly of the chestnut transcriptome of the resistant Euro-Japanese hybrid 'Bouche de Bétizac' (BB) and the susceptible cultivar 'Madonna' (M), collecting RNA from buds at different stages of budburst. The two transcriptomes were assembled into 34,081 (BB) and 30,605 (M) unigenes, respectively. The former was used as a reference sequence for further characterization analyses, highlighting the presence of 1444 putative resistance gene analogs (RGAs) and about 1135 unigenes, as putative MiRNA targets. A global quantitative transcriptome profiling comparing the resistant and the susceptible cultivars, in the presence or not of the gall wasp, revealed some GO enrichments as "response to stimulus" (GO:0050896), and "developmental processes" (e.g., post-embryonic development, GO:0009791). Many up-regulated genes appeared to be transcription factors (e.g., RAV1, AP2/ERF, WRKY33) or protein regulators (e.g., RAPTOR1B) and storage proteins (e.g., LEA D29) involved in "post-embryonic development". Our analysis was able to provide a large amount of information, including 7k simple sequence repeat (SSR) and 335k single-nucleotide polymorphism (SNP)/INDEL markers, and generated the first reference unigene catalog for the European Chestnut. The transcriptome data for C. sativa will contribute to understand the genetic basis of the resistance to gall wasp and will provide useful information for next molecular genetic studies of this species and its relatives.

Plant-Mediated Interaction: A First Record of Thrips Feeding on Hartigiola annulipes (Diptera: Cecidomyiidae) Galls

Galls formed by insects can act as sinks for nutrients and attract other herbivores to feed on gall tissues, which initiates interspecific competition, sometimes nurturing the herbivorous insects and restraining the gall-inducing insect, particularly when this competition is plant-mediated. Here, to our knowledge, we provide the first evidence of a close relationship between a gall insect, Hartigiola annulipes (Diptera: Cecidomyiidae), and a sap-sucking, Liothrips setinodis (Thysanoptera: Phlaeothripidae). The thrips were observed feeding on young H. annulipes galls, formed on the common beech (Fagus sylvatica) leaves during spring. Among randomly chosen beech trees, 100 current-year shoots were surveyed to determine the number of H. annulipes galls and the presence of thrips on the leaves. Our results show that L. setinodis specimens were found significantly more frequently on leaves infested by the galler than on uninfested leaves. The consequences of feeding thrips at the site of gall formation are not known yet, but it can be supposed that they are unfavourable to the gall insects and therefore could be beneficial for the host plant.

MULTI-PURPOSE CHESTNUT CLUSTERS DETECTION USING DEEP LEARNING: A PRELIMINARY APPROACH

Abstract. In the early 1980′s, the European chestnut tree (Castanea sativa, Mill.) assumed an important role in the Portuguese economy. Currently, the Trás-os-Montes region (Northeast of Portugal) concentrates the highest chestnuts production in Portugal, representing the major source of income in the region (€50M-€60M). The recognition of the quality of the Portuguese chestnut varieties has increasing the international demand for both industry and consumer-grade segments. As result, chestnut cultivation intensification has been witnessed, in such a way that widely disseminated monoculture practices are currently increasing environmental disaster risks. Depending on the dynamics of the location of interest, monocultures may lead to desertification and soil degradation even if it encompasses multiple causes and a whole range of consequences or impacts. In Trás-os-Montes, despite the strong increase in the cultivation area, phytosanitary problems, such as the chestnut ink disease (Phytophthora cinnamomi) and the chestnut blight (Cryphonectria parasitica), along with other threats, e.g. chestnut gall wasp (Dryocosmus kuriphilus) and nutritional deficiencies, are responsible for a significant decline of chestnut trees, with a real impact on production. The intensification of inappropriate agricultural practices also favours the onset of phytosanitary problems. Moreover, chestnut trees management and monitoring generally rely on in-field time-consuming and laborious observation campaigns. To mitigate the associated risks, it is crucial to establish an effective management and monitoring process to ensure crop cultivation sustainability, preventing at the same time risks of desertification and land degradation. Therefore, this study presents an automatic method that allows to perform chestnut clusters identification, a key-enabling task towards the achievement of important goals such as production estimation and multi-temporal crop evaluation. The proposed methodology consists in the use of Convolutional Neural Networks (CNNs) to classify and segment the chestnut fruits, considering a small dataset acquired based on digital terrestrial camera.

Insectos agalladores en los encinos (Quercus spp.) del parque estatal Cerro Gordo, Estado de México

El Parque estatal Cerro Gordo es una reserva constituida por áreas ejidales, comunales y privadas dentro del Valle de México. La vegetación nativa del parque está conformada por diversos taxa de encinos no identificados, y por lo menos dos de ellos están infestados con agallas, sobre todo en brotes y ramas; aunque, se desconoce la identidad del o de sus agentes causales. Por lo tanto, el objetivo de este trabajo consistió en identificar las especies de encinos, así como los insectos asociados a las agallas. Se eligieron y marcaron tres sitios dentro del parque, se colectaron ejemplares botánicos y mensualmente se recolectaron agallas en el periodo de febrero a julio del 2017. Las muestras vegetales se secaron, identificaron e integraron a la colección del herbario de la División de Ciencias Forestales de la Universidad Autónoma Chapingo. Las agallas se colocaron en cámaras de emergencia bajo condiciones controladas; los insectos se fijaron en etanol para su determinación taxonómica. Los encinos correspondieron a: Quercus laurina (número de registro 69 367), Q. crassipes (69 368), Q. rugosa (69 369) y Q. microphylla (69 370). En las agallas de las ramas de Q. microphylla, se registró la presencia de Andricus carrilloi, la de Synergus mexicanus como su inquilino y la de Synergus sp. en Q. crassipes se observó a Amphibolips hidalgoensis. Estos son los primeros registros tanto de los insectos formadores de agallas en la región del Valle de México, como de sus especies hospederas.

Insect galls on Bauhinia cupulata (Fabaceae): morphotypes characterization and description of a new species of Schizomyia (Cecidomyiidae, Diptera)

Galls on Bauhinia cupulata (Fabaceae) were investigated in two physiognomies of the Cerrado, riparian and dry forest, in the municipality of Barreiras (Western Bahia, Brazil) from October 2012 to July 2014. Four insect gall morphotypes were found. They were characterized based on shape, color, indumentum, plant organ of occurrence and galling taxon. A new galling species, Schizomyia barreirensis, is described, illustrated (larva, pupa, male, female and gall) and compared to other Neotropical congeneric species.

The early developmental stages of gall-inducing insects define final gall structural and histochemical profiles: the case of Bystracoccus mataybae galls on Matayba guianensis

Gall morphotypes depend on continuous chemical and feeding stimuli of the gall inducer, which promotes specific structural and metabolic changes in plant tissues. The galling insect manipulates host-plant tissues and may stimulate the production of primary and secondary metabolites. The type of chemical arsenal and the storage site varies according to the developmental potentials of the host plant and the insect’s feeding habit. Here, we investigated whether the structural and histochemical profiles of the gall system Matayba guianensis Aubl. (Sapindaceae) – Bystracoccus mataybae (Eriococcidae) are dependent on the instars of the galling insect. Standard anatomical analyses were carried out, as well as histochemical evaluation of reactive oxygen species and primary and secondary metabolites. Structural changes induced by the first instar nymphs were detected on the stem, while deep changes induced by the second instar nymphs and adult females were detected in leaflet galls, indicating that the host-plant tissue can impose more limits on gall development and complexity than the stages of galling insect development. The compartmentalization of primary and secondary compounds is established during the early stages of development of the leaflet gall by the second instar nymphs. Despite deep structural differences between stem and leaflet galls, there were no significant changes in the establishment of the histochemical profiles.

Heterogony in Cycloneuroterus (Hymenoptera: Cynipidae: Cynipini) From Rearing Experiments and DNA Barcoding.

Heterogony was confirmed in the cynipid genus Cycloneuroterus Melika and Tang in rearing experiments with DNA barcoding. These experiments involved Cycloneuroterus gilvus Tang and Melika, which was previously only described from the sexual generation adult. The first rearing experiment was conducted using unidentified asexual generation females collected from Quercus gilva Blume, and gall formation by the sexual generation offspring was confirmed on folded or unfolded young leaves of Q. gilva. The second experiment was conducted using sexual generation males and females reared from the leaf galls collected from Q. gilva, and gall formation by the asexual generation offspring was observed on leaves of Q. gilva. Based on the morphological features of the sexual generation adults and galls, this species was identified as C. gilvus. The species identity of wasp specimens of sexual and asexual generations used in the rearing experiments was cross-checked using DNA barcoding with the partial sequences of the cytochrome c oxidase subunit I (COI) region (658 bp). The asexual generation adult and gall of C. gilvus are described based on these results. The importance of ‘closing the life cycle,’ in this case a demonstration of heterogony, in oak gall wasps (Cynipini) is discussed.