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Evaluation of host-plant resistance on sugarcane to the sugarcane stem borers of Diatraea spp. is normally conducted in Colombia under field conditions, where environmental variations make the study of the insect-plant relationships difficult. Additionally, several species (i.e., D. saccharalis, D. indigenella, D. tabernella, and D. busckella), which are predominant in Colombia, can overlap in their distribution, raising the question of whether different varieties have the same responses to different pest species. The present study conducted evaluations of host-plant resistance under screen house conditions using two contrasting varieties (CC 93-3895, resistant, and CC 93-3826, susceptible) that were infested with the above-mentioned borer species. Observations of pest injury were conducted on internodes, leaves, and spindles. Survival and size (body mass) of the individuals recovered were analyzed and a Damage Survival Ratio (DSR) was proposed. The resistant CC 93-3895 exhibited less stalk injury, less emergence holes on internodes, and lower DSR; additionally, recovery of pest individuals was lower in comparison with CC 93-3826, independent of the borer species. Insect-plant interactions are discussed, as no previous information was available for three of the species tested (i.e., D. tabernella, D. indigenella, and D. busckella). This screen house protocol is proposed to characterize host-plant resistance among several cultivars from the Colombian sugarcane germplasm bank, using CC 93-3826 and CC 93-3895 as contrasting controls and D. saccharalis as the species model.

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Anastrepha spp. (Diptera: Tephritidae) infestations cause significant economic losses in commercial fruit production worldwide. However, some plants quickly counteract the insertion of eggs by females by generating neoplasia and hindering eclosion, as is the case for Persea americana Mill., cv. Hass (Hass avocados). We followed a combined transcriptomics/metabolomics approach to identify the molecular mechanisms triggered by Hass avocados to detect and react to the oviposition of the pestiferous Anastrepha ludens (Loew). We evaluated two conditions: fruit damaged using a sterile pin (pin) and fruit oviposited by A. ludens females (ovi). We evaluated both of the conditions in a time course experiment covering five sampling points: without treatment (day 0), 20 min after the treatment (day 1), and days 3, 6, and 9 after the treatment. We identified 288 differentially expressed genes related to the treatments. Oviposition (and possibly bacteria on the eggs' surface) induces a plant hypersensitive response (HR), triggering a chitin receptor, producing an oxidative burst, and synthesizing phytoalexins. We also observed a process of cell wall modification and polyphenols biosynthesis, which could lead to polymerization in the neoplastic tissue surrounding the eggs.

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Plants have evolved multiple mechanisms to defend themselves from their multiple herbivores. Thus, being able to recognise among them and respond accordingly is fundamental for plant survival and reproduction. Defence priming prepares the plant to better or more rapidly respond to future damage; however, while it is considered an adaptive trait, to date, no studies have evaluated the extent and specificity of the priming recognition. To estimate the costs, benefits and specificity of priming, we used a highly specialist plant-insect system (Datura stramonium-Lema daturaphila) and performed a reciprocal transplant experiment with two populations where a priming stimulus (sympatric vs. allopatric) and a damage treatment (sympatric) were applied. We found no evidence of a fitness cost of priming, given that primed plants without damage showed no reduction in fitness. In contrast, our treatments affected the probability of bud abortion. That is, when damaged plants received no priming or the priming came from an allopatric insect, the likelihood of aborting the first bud was 1.9 times greater compared to plants being primed by their sympatric insect. We also found that damaged plants primed with an allopatric insect produced 14% fewer seeds compared to plants receiving a sympatric priming stimulus. Tolerance to herbivore damage was also the lowest when plants received the priming stimulus from an allopatric insect. Overall, these results suggest that, in our study system, plants recognise their local insect population reducing the negative effect of damage through a tolerance response.

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Nectar plays important roles in the relationship between plants and other organisms, both within pollination systems and as a defense mechanism. In the latter case, extranuptial nectaries (ENNs) usually attract patrolling arthropods that reduce herbivory. ENNs have been frequently reported within the "xeric clade" of Bromeliaceae, but their occurrence in other groups of bromeliads is largely unexplored, especially considering their position, secretory activity and structure. After observing the presence of ants constantly patrolling the inflorescences of Pitcairnia burchellii Mez, we searched for the presence, secretory activity, and structure of ENNs in this species. We also provide a brief review of the occurrence ENNs in Bromeliaceae. The distribution of nectaries was assessed using ant-exclusion experiments, while structural analysis was performed using standard methods for light and scanning electron microscopy. The presence of sugars in the secretion was assessed by thin-layer chromatography and glucose strip tests. Nectaries in P. burchelli are non-structured glands on the adaxial surface of floral bracts and sepals. Bracts and sepals are distinct spatial units that act over time in the same strategy of floral bud protection. Literature data reveals that ENNs might be more common within Bromeliaceae than previously considered, comprising a homoplastic feature in the family. Future perspectives and evolutionary and taxonomic implications are discussed.

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Plant natriuretic peptide-like (PNP) are signaling molecules related to adaptive responses to stress. The Arabidopsis thaliana PNP (AtPNP-A) is capable of modulating catalase 2 (CAT2) and rubisco activase (RCA) activity in some circumstances. Interestingly, many plant-pathogens co-opted PNP-like molecules to their benefit. For instance, the citrus pathogen Xanthomonas citri carries a PNP-like (XacPNP) that can mimic and regulate plant homeostasis, and many phytopathogenic fungi carry effectors (e.g., Ave1 and AvrLm6) that are indeed PNP-like homologs. This work investigates the PNP-like evolution across the tree of life, revealing many parallel gains and duplications in plant and fungi kingdoms. All PNP-like proteins in the final dataset are structurally similar, containing the AtPNP-A active domains modulating CAT2 activity and RCA interaction. Comparative genomics evinced that XacPNP is a lysogenic conversion factor associated with a Myoviridae-like prophage identified in many Xanthomonas species. Surprisingly, a PNP-like homolog was identified in Bemisia tabaci, an important agricultural pest, being to date the second example of lateral gene transfer (LGT) from plant to the whitefly. Moreover, the Bemisia PNP-like homolog can also be considered a potential new effector of this phloem-feeding insect. Noteworthy, the whiteflies infest many plants carrying PNP-like copies and interact with some of their bacterial and fungal pathogens, strongly suggesting complex recipient/donor traits of PNP by LGT and bringing new insights into the evolution of host-pathogen arms race across the tree of life.

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The Bemisia tabaci (Gennadius) whitefly is a major economically damaging pest of many crops such as tomato (Solanum lycopersicum L.). Pesticides are widely used to control B. tabaci while the use of aromatic plants is an alternative control method. The aim of this study was to assess the B.tabaci repellent effect of wild oregano, Plectranthus amboinicus (Lour.) Spreng, a widespread aromatic plant in the West Indies. We tested three origins of wild oregano, including northern, central, and southern Martinique (French West Indies). Our results showed that all essential oils of wild oregano had either masking properties or were true repellents-the mean percentage of whiteflies present in the upper part of the still-air olfactometer was 1.3- to 1.9-fold lower than in the controls. The ethanolic solution of volatile organic compounds of wild oregano from southern Martinique also had a true repellent effect-the mean percentage of whiteflies present in the upper part of the still-air olfactometer was 1.3-fold lower than in the controls. Moreover, in a greenhouse insect-proof cage, there were 1.5 fewer adult whiteflies on tomato intercropped with wild oregano from southern Martinique than on tomato alone after 96 h exposure. Our study generated further insight into the potential of P. amboinicus for B. tabaci biocontrol on tomato crops. Wild oregano extracts were repellent to B. tabaci and could be used as a companion plant to prevent whitefly infestations on tomato crops. However, the B. tabaci behavior depends on the plant origin.

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We studied the microbiota of a highly polyphagous insect, Anastrepha ludens (Diptera: Tephritidae), developing in six of its hosts, including two ancestral (Casimiroa edulis and C. greggii), three exotic (Mangifera indica cv. Ataulfo, Prunus persica cv. Criollo, and Citrus x aurantium) and one occasional host (Capsicum pubescens cv. Manzano), that is only used when extreme drought conditions limit fruiting by the common hosts. One of the exotic hosts ("criollo" peach) is rife with polyphenols and the occasional host with capsaicinoids exerting high fitness costs on the larvae. We pursued the following questions: (1) How is the microbial composition of the larval food related to the composition of the larval and adult microbiota, and what does this tell us about transience and stability of this species' gut microbiota? (2) How does metamorphosis affect the adult microbiota? We surveyed the microbiota of the pulp of each host fruit, as well as the gut microbiota of larvae and adult flies and found that the gut of A. ludens larvae lacks a stable microbiota, since it was invariably associated with the composition of the pulp microbiota of the host plant species studied and was also different from the microbiota of adult flies indicating that metamorphosis filters out much of the microbiota present in larvae. The microbiota of adult males and females was similar between them, independent of host plant and was dominated by bacteria within the Enterobacteriaceae. We found that in the case of the "toxic" occasional host C. pubescens the microbiota is enriched in potentially deleterious genera that were much less abundant in the other hosts. In contrast, the pulp of the ancestral host C. edulis is enriched in several bacterial groups that can be beneficial for larval development. We also report for the first time the presence of bacteria within the Arcobacteraceae family in the gut microbiota of A. ludens stemming from C. edulis. Based on our findings, we conclude that changes in the food-associated microbiota dictate major changes in the larval microbiota, suggesting that most larval gut microbiota is originated from the food.

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Introduction: Annona macroprophyllata Donn. Smith. (Annonaceae) (syn. Annona diversifolia Saff.) is a valued fruit tree species known as papausa. In Mexico and Central America, this fruit has become an important crop because of its tasty flavor and high pulp content. Its fruits are frequently damaged by the incidence of wasps of the genus Bephratelloides Girault (Hymenoptera: Eurytomidae), which develop inside the seeds. Objective: To report the interaction of Bephratelloides cubensis Ashmead during its life cycle in fruits of A. macroprophyllata. Methods: We periodically collected fruits in different states of growth recording a) oviposition, b) the moment of evident infection, c) the development of the wasps inside the seeds, and d) their emergence as adults. We also determined the proportion of damaged fruits and seeds. Results: The data indicate that wasps preferred to oviposit on fruits with a diameter of less than 8 cm, oviposition was more frequent between 11:00 am and 03:00 pm., and there was 26 % infestation of fruits, and 9 % of seeds. Conclusion: It is an obligatory interaction for the wasp, the highest proportion of attack on fruits was in the early stages of fruit development and control actions should focus on the protection of these early stages.

Introducción: Annona macroprophyllata Donn. Smith. (Annonaceae) es una especie de árbol frutal, conocida como papausa. En México y América Central, esta fruta se ha convertido en un cultivo importante y valorado debido a su delicioso sabor y la cremosa textura de su pulpa. Sus frutos son frecuentemente dañados por la incidencia de avispas del género Bephratelloides Girault (Hymenoptera: Eurytomidae), que se desarrollan dentro de las semillas. Objetivo: Describir la interacción de Bephratelloides cubensis Ashmead durante su ciclo de vida en frutos de A. macroprophyllata. Método: Recolectamos frutos en diferentes estados de crecimiento registrando a) la ovoposición, b) el momento de la infección evidente, c) el desarrollo de las avispas dentro de las semillas, y d) su emergencia como adultos. También determinamos la proporción de frutas y semillas dañadas. Resultados: Los datos indican que las avispas preferían ovipositar en frutas con un diámetro de menos de 8 cm, la oviposición era más frecuente entre las 11:00 a.m. y las 3:00 p.m., y que había un 26 % de la infestación en las frutas y un 9 % en semillas. Conclusión: Es una interacción obligada para la avispa y la mayor proporción de ataque a los frutos fue en las etapas tempranas de desarrollo de frutos y las acciones de control se deberían enfocar a la protección de estas etapas.

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Cuticular ridges on plant surfaces can control insect adhesion and wetting behaviour and might also offer stability to underlying cells during growth. The growth of the plant cuticle and its underlying cells possibly results in changes in the morphology of cuticular ridges and may also affect their function. We present spatial and temporal patterns in cuticular ridge development on the leaf surfaces of the model plant, Hevea brasiliensis. We have identified, by confocal laser scanning microscopy of polymer leaf replicas, an acropetally directed progression of ridges during the ontogeny of Hevea brasiliensis leaf surfaces. The use of Colorado potato beetles (Leptinotarsa decemlineata) as a model insect species has shown that the changing dimensions of cuticular ridges on plant leaves during ontogeny have a significant impact on insect traction forces and act as an effective indirect defence mechanism. The traction forces of walking insects are significantly lower on mature leaf surfaces compared with young leaf surfaces. The measured walking traction forces exhibit a strong negative correlation with the dimensions of the cuticular ridges.

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The botanical source of Brazilian green propolis (BGP) is Baccharis dracunculifolia DC, which interacts not only with Apis mellifera, but also with galling insects. In the last decade, because of green propolis´ important biologic activities, the international demand for BGP overcame the production capacity, consequently, new approaches are required to increase this production. Hence, the understanding of the chemical ecology interactions of B. dracunculifolia with galls and bees in field conditions may provide insights to increase BGP's production. A "bee pasture" experiment aiming to better understand this plant-insect interaction was therefore performed. For that, 48 B. dracunculifolia individuals, being 24 females and 24 males, were cultivated and investigated for the following parameters: (1) phenolic and volatile compounds in both B. dracunculifolia leaves and green propolis, (2) environmental variables, (3) visiting rate by bees, (4) time of resin collection, and (5) number of galls. Regression analyses by independent linear mixed-effect models were run to correlate phenolic and volatile compounds concentration with the environmental and field variables. Significant differences in chemical profile and field variables were observed between male and female plants. Male plants showed higher infestation by galling insects while female plants showed higher number of visiting bees, time of resin collection and terpenes concentration, contributing to the differences observed in the field. The obtained results suggest that increasing the percentage of female B. dracunculifolia plants in the field may attract more bees and therefore enhance propolis production.

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Host plants may harbor a variable number of galling insect species, with some species being able to harbor a high diversity of these insects, being therefore called superhost plants. In the present study, we tested the hypothesis that the occurrence of superhost plant species of genus Qualea (Vochysiaceae) affects the structure of plant-galling insect ecological networks in Brazilian Cerrado. We sampled a total of 1882 plants grouped in 131 species and 43 families, of which 64 species and 31 families of host plants hosted 112 galling insect species. Our results showed that occurrence of superhosts of genus Qualea increased the linkage density of plant species, number of observed interactions, and the size of plant-galling insect networks and negatively affected the network connectance (but had no effect on the residual connectance). Although the occurrence of Qualea species did not affect the plant species richness, these superhosts increased the species richness and the number of interactions of galling insects. Our study represents a step forward in relation to previous studies that investigated the effects of plant diversity on the plant-insect networks, showing that few superhost plant species alter the structure of plant-herbivore networks, even without having a significant effect on plant diversity.

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Plants are able to sense their environment and respond appropriately to different stimuli. Vibrational signals (VS) are one of the most widespread yet understudied ways of communication between organisms. Recent research into the perception of VS by plants showed that they are ecologically meaningful signals involved in different interactions of plants with biotic and abiotic agents. We studied changes in the concentration of alkaloids in tobacco plants induced by VS produced by Phthorimaea operculella (Lepidoptera: Gelechiidae), a generalist caterpillar that naturally feeds on the plant. We measured the concentration of nicotine, nornicotine, anabasine and anatabine in four treatments applied to 11-weeks old tobacco plant: a) Co = undamaged plants, b) Eq = Playback equipment attached to the plant without VS, c) Ca = Plants attacked by P. operculella herbivory and d) Pl = playback of VS of P. operculella feeding on tobacco. We found that nicotine, the most abundant alkaloid, increased more than 2.6 times in the Ca and Pl treatments as compared with the Co and Eq treatments, which were similar between them. Nornicotine, anabasine and anatabine were mutually correlated and showed similar concentration patterns, being higher in the Eq treatment. Results are discussed in terms of the adaptive significance of plant responses to ecologically important VS stimuli.

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Understanding sugarcane (Saccharum spp.) response to multiple pest injury, sugarcane borer (Diatraea saccharalis) and spittlebug (Mahanarva fimbriolata), is essential to make better management decisions. Moreover, the consequences of both pests on the sugarcane raw material quality have not yet been studied. A field experiment was performed in São Paulo State, Brazil, where sugarcane plants were exposed to pests individually or in combination. Plots consisted of a 2-m long row of caged sugarcane plants. Photosynthesis was measured once every 3 months (seasonal measurement). Yield and sugar production were assessed. The measured photosynthesis rate was negatively affected by both borer and spittlebug infestations. Photosynthesis reduction was similar on plants infested by both pests as well as by spittlebug individual infestation. Plants under spittlebug infestation resulted in yield losses and represented 17.6% (individual infestation) and 15.5% (multiple infestations). The sucrose content and the sucrose yield per area were reduced when plants were infested by multiple pests or spittlebug.

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Thysanoptera-induced galls commonly culminate in simple folding or rolling leaf gall morphotypes. Most of these galls are induced by members of the suborder Tubulifera, with only a few species of the suborder Terebrantia being reported as gall inducers. The Terebrantia, as most of the gall inducers, manipulates the host plant cellular communication system, and induces anatomical and biochemical changes in its host plant. In an effort to keep its homeostasis, the host plant reacts to the stimuli of the galling insect and triggers chemical signaling processes. In contrast to free-living herbivores, the signaling processes involving galling herbivores and their host plants are practically unknown. Current investigation was performed into two steps: first, we set the structural profile of non-galled and galled leaves, and looked forward to find potential alterations due to gall induction by an undescribed species of Nexothrips (suborder Terebrantia) on Myrcia splendens. Once oil glands had been altered in size and number, the second step was the investigation of the chemical profile of three tissue samples: (1) non-galled leaves of a control individual, (2) non-galled leaves of galled plants, and (3) galls. This third sample was divided into two groups: (3.1) galls from which the inducing thrips were manually removed and (3.2) galls macerated with the inducing thrips inside. The chemical profile was performed by gas chromatography/ mass spectrometric detector after headspace solid-phase extraction. The galling activity of the Nexothrips sp. on M. splendens culminates in mesophyll compactness interspersed to diminutive hypersensitive spots, development of air cavities, and the increase in size and number of the secretory glands. Seventy-two compounds were completely identified in the volatile profile of the three samples, from which, sesquiterpenes and aldehydes, pertaining to the "green leaf volatile" (GLVs) class, are the most abundant. The rare event of gall induction by a Terebrantia revealed discrete alterations toward leaf rolling, and indicated quantitative differences related to the plant bioactivity manipulated by the galling thrips. Also, the content of methyl salicylate has varied and has been considered a potential biomarker of plant resistance stimulated as a long-distance effect on M. splendens individuals.

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Diaphorina citri is a vector of the bacterial causative agent of Huanglongbing (HLB = Citrus greening), a severe disease affecting citrus crops. As there is no known control for HLB, manipulating insect behaviour through deployment of semiochemicals offers a promising opportunity for protecting citrus crops. The behavioural responses of D. citri to plant volatiles, and the identity of these plant volatiles were investigated. Volatiles were collected from host plants Murraya paniculata, Citrus sinensis, C. reshni, C. limettioides, Poncirus trifoliata, and from non-host plants Psidium guajava, Mangifera indica, Anacardium occidentale. In behavioural assays, female D. citri spent more time in the arms containing volatiles from either M. paniculata or C. sinensis compared to the control arms. When D. citri was exposed to volatiles collected from A. occidentale, they preferred the control arm. Volatiles emitted from the other studied plants did not influence the foraging behaviour of D. citri. Chemical analyses of volatile extracts from C. sinensis, M. paniculata, and A. occidentale revealed the presence of the terpenoids (E)-4,8-dimethylnona-1,3,7-triene (DMNT) and (E,E)-4,8,12-trimethyltrideca-1,3,7,11-tetraene (TMTT) in higher amounts in A. occidentale. In further behavioural bioassays, female D. citri spent less time in arms containing a synthetic blend of DMNT and TMTT compared to the control arms. Female D. citri also spent less time in arms containing the synthetic blend in combination with volatile extracts from either M. paniculata or C. sinensis compared to the control arms. Results suggest that higher release of the two terpenoids by A. occidentale make this species unattractive to D. citri, and that the terpenoids could be used in reducing colonisation of citrus plants and therefore HLB infection.

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ABSTRACT We studied the volatile composition and sexual morphs of Nephelium lappaceum flowers from two orchards, and investigated the choice behavior of the honey bee, Apis mellifera toward the floral extracts from both locations. Our results showed significant differences in chemical composition and sexual morphs; only the hermaphrodite flowers from the Herradero orchard produced limonene and α-pinene and had longer peduncle and sepal than flowers from the Metapa orchard; on the other hand, the hermaphrodite flowers from the Metapa orchard had longer gynoecium. In the behavioral experiment the extracts from the Herradero orchard seemed to give A. mellifera foragers better cues for orientation to food sources, perhaps due to the presence of limonene and α-pinene, which are absent in the samples from Metapa. Such differences in both orchards could affect pollinator attraction and ultimately seed set and productivity.

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Solar UV-B radiation has been reported to enhance plant defenses against herbivore insects in many species. However, the mechanism and traits involved in the UV-B mediated increment of plant resistance are unknown in crops species, such as soybean. Here, we studied defense-related responses in undamaged and Anticarsia gemmatalis larvae-damaged leaves of two soybean cultivars grown under attenuated or full solar UV-B radiation. We determined changes in jasmonates, ethylene (ET), salicylic acid, trypsin protease inhibitor activity, flavonoids, and mRNA expression of genes related with defenses. ET emission induced by Anticarsia gemmatalis damage was synergistically increased in plants grown under solar UV-B radiation and was positively correlated with malonyl genistin concentration, trypsin proteinase inhibitor activity and expression of IFS2, and the pathogenesis protein PR2, while was negatively correlated with leaf consumption. The precursor of ET, aminocyclopropane-carboxylic acid, applied exogenously to soybean was sufficient to strongly induce leaf isoflavonoids. Our results showed that in field-grown soybean isoflavonoids were regulated by both herbivory and solar UV-B inducible ET, whereas flavonols were regulated by solar UV-B radiation only and not by herbivory or ET. Our study suggests that, although ET can modulate UV-B-mediated priming of inducible plant defenses, some plant defenses, such as isoflavonoids, are regulated by ET alone.

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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.

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Although it is well known that solar ultraviolet B (UV-B) radiation enhances plant defenses, there is less knowledge about traits that define insect resistance in field-grown soybean. Here we study the effects of solar UV-B radiation on: a) the induction of phenolic compounds and trypsin proteinase inhibitors (TPI) in soybean undamaged leaves or damaged by Anticarsia gemmatalis neonates during six days, and b) the survival and mass gain of A. gemmatalis larvae that fed on soybean foliage. Two soybean cultivars (cv.), Charata and Williams, were grown under plastic with different transmittance to solar UV-B radiation, which generated two treatments: ambient UV-B (UVB+) and reduced UV-B (UVB-) radiation. Solar UV-B radiation decreased survivorship by 30% and mass gain by 45% of larvae that fed on cv. Charata, but no effect was found in those larvae that fed on cv. Williams. TPI activity and malonyl genistin were induced by A. gemmatalis damage in both cultivars, but solar UV-B radiation and damage only synergistically increased the induction of these compounds in cv. Williams. Although TPI activity and genistein derivatives were induced by herbivory, these results did not explain the differences found in survivorship and mass gain of larvae that fed on cv. Charata. However, we found a positive association between lower larval performance and the presence of two quercetin triglycosides and a kaempferol triglycoside in foliage of cv. Charata, which were identified by HPLC-DAD/MS2. We conclude that exclusion of solar UV-B radiation reduce resistance to A. gemmatalis, due to a reduction in flavonol concentration in a cultivar that has low levels of genistein derivatives like cv. Charata.

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BACKGROUND: Southern green stink bugs (Nezara viridula L.) invade field-grown soybean crops, where they feed on developing seeds and inject phytotoxic saliva, which causes yield reduction. Although leaf responses to herbivory are well studied, no information is available about the regulation of defences in seeds. RESULTS: This study demonstrated that mitogen-activated protein kinases MPK3, MPK4 and MPK6 are expressed and activated in developing seeds of field-grown soybean and regulate a defensive response after stink bug damage. Although 10-20 min after stink bug feeding on seeds induced the expression of MPK3, MPK6 and MPK4, only MPK6 was phosphorylated after damage. Herbivory induced an early peak of jasmonic acid (JA) accumulation and ethylene (ET) emission after 3 h in developing seeds, whereas salicylic acid (SA) was also induced early, and at increasing levels up to 72 h after damage. Damaged seeds upregulated defensive genes typically modulated by JA/ET or SA, which in turn reduced the activity of digestive enzymes in the gut of stink bugs. Induced seeds were less preferred by stink bugs. CONCLUSION: This study shows that stink bug damage induces seed defences, which is perceived early by MPKs that may activate defence metabolic pathways in developing seeds of field-grown soybean. © 2015 Society of Chemical Industry.

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