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Arthropod-Plant Interactions
Journal Prestige (SJR): 0.839  Citation Impact (citeScore): 2 Number of Followers: 2  Hybrid journal (It can contain Open Access articles)ISSN (Print) 1872-8847 - ISSN (Online) 1872-8855 Published by Springer-Verlag  [2469 journals]
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- Herbivory changes biomass allocation but does not induce resistance among
ramets of an invasive plant-
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Abstract: Abstract Inducible responses to herbivores can be either localized or spread systemically throughout a plant. The ways in which clonal plants integrate their response to herbivores among clonal ramets is not well understood. Yet, this is important to understand the impacts that herbivores may have on clonal plants. We conducted a factorial split-plot greenhouse experiment to determine whether resistance is induced among ramets and how biomass allocation changes among ramets following herbivore damage to one of them. We manipulated the presence of two herbivores, Pieris rapae and Trichoplusia ni, and the root connection of ramets of the clonal invasive weed, Lepidium draba. We found local inducible resistance on the ramet where an herbivore fed, but not in neighboring ramets. Biomass allocation shifted in response to herbivores. Feeding by the generalist caterpillar T. ni resulted in a greater belowground biomass relative to shoot biomass in the local plant, but only when the clonal connection was intact. In contrast, herbivores had little impact on the root mass fraction of neighboring ramets. Herbivory to the local ramet increased the regrowth of neighboring ramets that lacked clonal connection, a trend that was driven by the specialist herbivore P. rapae. Herbivores did not induce systemic resistance among ramets of L. draba, but herbivores, especially the specialist, did alter how neighboring ramets regrow after grazing or mowing. Our observations suggest that individual ramets have fairly autonomous responses to herbivores, and that coordination among ramets, when present, may happen via signals that do not depend on root connections.
PubDate: 2022-05-04
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- Interaction between feeding efficiency and digestive physiology of the
pink stem borer, Sesamia cretica Lederer (Lepidoptera: Noctuidae), and
biochemical compounds of different sugarcane cultivars-
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Abstract: Abstract The pink stem stalk borer, Sesamia cretica Lederer, is the main insect pest of sugarcane, Saccharum officinarum L., in Iran and worldwide. This paper assesses the effects of six sugarcane cultivars on the feeding performance and enzymatic activity of S. cretica under controlled conditions. It also investigates the biochemical traits of sugarcane cultivars (total phenolic, flavonoids, and anthocyanins contents) and explores their relationship with the nutritional physiology of S. cretica. The study findings indicated remarkable differences in the nutritional properties and digestive function of S. cretica on various sugarcane cultivars. The S. cretica larvae reared on cultivar CP48-103 were indicated to have the highest ECI, RGR, and ECD values. In addition, the larvae fed on cultivar CP73-21 showed the lowest values of RCR and RGR. The S. cretica larvae induced the highest proteolytic activity during feeding with CP48-103, CP57-614, and CP73-21 cultivars. The fifth instar larvae demonstrated the highest and lowest amylolytic activity when fed with cultivars IRC99-01 and CP57-614, respectively. Moreover, significant variations in the phytochemical metabolites were detected among the sugarcane cultivars. Significant negative or positive correlations were found between the tested parameters of S. cretica and the biochemical characteristics of sugarcane cultivars. The cluster analysis results showed that cultivar CP73-21 was relatively unsuitable for S. cretica feeding: it was a suggested candidate to grow in regions with typically high pest infestation.
PubDate: 2022-05-02
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- Pollinator efficiency in openly grown eggplants: can non-vibrating bees
produce high-quality fruits'-
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Abstract: Abstract In the face of the global decline in pollinator populations, studies that serve as a basis for the conservation and management of crop pollinators are crucial. The eggplant (Solanum melongena) is a widely cultivated autogamous crop, whose production is favoured by pollination by vibrating (buzz pollinating bees). To our knowledge, thus far, no studies have tested for the pollination efficiency of non-vibrating bees, nor have any been conducted in semi-arid regions, or evaluated the influence of pollination on the chemical characteristics of the fruits. Here, we evaluated the influence of pollination by vibrating and non-vibrating pollinators on eggplant fruit set and fruit traits in two plantations within the semi-arid region of NE Brazil. We conducted 120 h of focal observations and compared the fruit set and size (weight, length, and basal and apical diameters) under different pollination treatments (open pollination, spontaneous self-pollination, hand-cross pollination and single visits by different species of pollinating bees). Nine visiting bee species were recorded, which differed in visiting frequency and behaviour, as well as in pollination efficiency. Although being autogamous, plants visited by the vibrating bee Xylocopa sp. set more fruits than open, spontaneous self- and cross-pollination. However, the fruits produced by Xylocopa sp. were lighter and smaller than those obtained through open pollination, highlighting the importance of multiple pollinator visits or pollinator diversity. Non-vibrating pollinators contributed to fruit production quantity and quality. Fruits resulting from open, hand cross-pollination and both vibrating (Euglossa sp. 1) and non-vibrating bees (Paratrigona sp.) were larger than those resulting from spontaneous self-pollination. Pollination treatments had no influence on fruit chemical properties. Our results highlight the importance of pollination to eggplant production and the benefits of both vibrating and non-vibrating pollinators.
PubDate: 2022-04-01
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- Adhesive secretion in Schizolobium parahyba (Vell.) Blake (Leguminosae:
Caesalpinioideae): histochemical and morpho-functional characterization of
this unusual feature in woody plants-
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Abstract: Abstract The legume tree Schizolobium parahyba from the Brazilian Atlantic Forest shows young aerial organs covered with a sticky exudate. Aiming to clarify the functional aspects of the sticky secretions, we performed analyses on the dynamics of secretion through the plant development and characterized the chemical nature of the exudates by histochemical tests. We also studied the secretory tissue using light and electron microscopy. The production of the exudates starts soon after seed germination, being evident in the epicotyl but not in the hypocotyl and cotyledons. The secretory activity extends throughout the juvenile and pre-reproductive phase, in primary stems and leaf portions. After the first flowering, secretion was no longer observed. The lipid exudates are secreted by the epidermis and are composed of mixtures of essential oils and oleoresins. Modified plastids, extensive rough endoplasmic reticulum, proliferated smooth endoplasmic reticulum, enlarged vacuoles containing flocculant materials, membrane debris, and convoluted tubules/lamellae membranes covered with osmiophilic deposits are the main features of the secretory epidermal cells. Secretion exits the protoplast by exocytosis and accumulates in the cuticle, resulting in a sheath of concentric bands of electron-dense deposits, and is released by cuticle peeling. The hydrophobic nature of the secretion, which forms an impermeable layer on the epidermis of young organs, is a relevant attribute of the aerial organs of S. parahyba. In addition to protecting against desiccation, this exudate effectively captures particles and immobilizes insects and other arthropods.
PubDate: 2022-04-01
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- Ficus trees with upregulated or downregulated defence did not impact
predation on their neighbours in a tropical rainforest-
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Abstract: Abstract Trees can emit volatile organic compounds (VOCs) when under attack by herbivores, and these signals can also be detected by natural enemies and neighbouring trees. There is still limited knowledge of intra- and inter-specific communication in diverse habitats. We studied the effects of induced VOC emissions by three Ficus species on predation on the focal Ficus trees in a lowland tropical rainforest in Papua New Guinea. Further we assessed predation across a phylogenetically diverse set of neighbouring tree species. Two of the focal tree species, Ficus pachyrrhachis and F. hispidioides, have strong alkaloid-based constitutive defences while the third one, F. wassa, is lower in constitutive chemical defences. We experimentally manipulated the jasmonic acid signalling pathway by spraying the focal individuals with either methyl jasmonate (MeJA) or diethyldithiocarbamic acid (DIECA). These treatments induce increases or decreases in VOC emissions, respectively. We tested the possible effects of VOC emissions on each focal Ficus tree and two of its neighbours by measuring the predation rate of plasticine caterpillars. We found that predation increased after the MeJA application in only one focal tree species, F. wassa, while the DIECA application had no effect on any of the three focal species. Further, we did not detect an effect of our treatments on predation rates across neighbouring trees. Neither the phylogenetic distance of the neighbouring tree from the focal tree nor the physical distance from the focal tree had any effect on predation rates for any of the three focal Ficus species. These results suggest that even congeneric tree species vary in their response to the MeJA and DIECA treatment and subsequent response to VOC emissions by predators. Our results also suggest that MeJA effects did not spill over to neighbouring trees in highly diverse tropical rainforest vegetation.
PubDate: 2022-03-26
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- Generalist flower-visiting hoverflies as non-negligible actors in pollen
transport network in a botanical garden: verification of a hoverfly pollen
transport network using pollen DNA barcoding-
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Abstract: Abstract Botanical gardens could serve as pollinator-friendly gardens and are suitable locations for investigating plant–pollinator interactions. Pollination in botanical gardens is a challenging topic of research, and its ecological function remains unclear in terms of pollination management for both pollinators and plants. Objective monitoring methods—including the selection of insect taxa and analytical methods—are required to elucidate plant–pollinator interactions in botanical gardens. In this study, we evaluated pollen transport networks using generalist hoverflies, as they are important pollinator insects, generalist flower visitors, and heterospecific pollen vectors that carry pollen over large distances. Hoverflies can form generalized pollen transport networks with an adequate abundance and wide distribution, and are easily collectable using sticky traps. Pollen grains on hoverfly bodies were identified based on pollen DNA barcoding using the ITS, rbcL, and trn regions. Bipartite pollen transport networks in the study period in 2018 and 2019 consisted of 116 plant taxa that were significantly generalized and showed similar structures in both years. The dominant plant taxa were two invasive species—Solidago canadensis and Bidens sp.—which had a significantly high eigenvector centrality in unipartite pollen transport networks. Hoverfly-mediated pollen transfer distances were 116–131 m on average and were significantly shorter in heterogeneous open environments. These findings suggest that hoverflies are non-negligible actors in pollen transport networks in the studied botanical garden.
PubDate: 2022-03-22
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- Feeding and oviposition by the brown marmorated stink bug, Halyomorpha
halys (Stål) induce direct and systemic changes in volatile compound
emissions from potted peach and tree of heaven-
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Abstract: Abstract The invasive brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), has disrupted integrated pest management programs in agroecosystems including tree fruit in North America and several other regions worldwide. While the toolbox for managing the pest continues to grow, it has not yet been determined if feeding or oviposition by H. halys onto orchard or forest trees induces changes in volatiles emitted from trees that could be exploited by foraging egg parasitoids or other insects. The goal of this study was to investigate differences in volatile compound emissions from branches of potted peach and tree of heaven exposed directly and systemically to H. halys feeding and oviposition. Analyses indicate that H. halys feeding and oviposition induced changes in both the blend and specific amounts of volatile compounds emitted from both tree species. Tree of heaven branches directly exposed to H. halys oviposition and feeding emitted nerolidol at a higher rate than those exposed to feeding alone and control trees. Tree of heaven compound leaves systemically exposed to H. halys feeding alone emitted higher rates of (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) than trees exposed to oviposition and feeding or control trees. Conversely, for peach, both branches exposed directly or systemically resulted in a decrease in cis-3-hexenyl acetate when exposed to H. halys oviposition. Such changes in plant volatile compounds, or blends of compounds, have the potential to be used by foraging natural enemies of H. halys.
PubDate: 2022-03-21
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- Habitat as a conditionality factor of ant-plant mutualistic interaction in
the Cecropia-Azteca system-
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Abstract: Abstract Several aspects of the Cecropia-Azteca mutualism can vary across space and time. The present study explored this variation by focusing on correlations between morphophysiological characteristics of Cecropia pachystachya plants and the sizes of the populations of their breeding ant colonies (Azteca ovaticeps and A. alfari) in secondary forest and pasture habitats in the Atlantic Forest. We hypothesize that forest plants are (i) larger and (ii) harbor more populous colonies than pasture plants. More populous colonies have a greater number of workers to defend their host plant, so we hypothesize that aggressiveness depends on the (iii) ant species and habitat. In each habitat, we collected 60 plants hosting Azteca colonies (queen, worker, immature, and winged individuals). The heights and stem diameters of the plants were measured and the Müllerian bodies were counted. We counted the number of workers, immature individuals, and winged individuals as an indicator of the size of the Azteca populations. We conducted aggressive behavior tests among individuals from 35 different colonies. In general, plants and colonies were smaller in the pasture than in the forest. In both habitats, the populations of A. ovaticeps were larger than those of A. alfari, but they were not more aggressive. The habitat directly influenced the physical structures of the plants and those in turn influenced the size of the ant populations. The conversion of forests into simplified habitats such as pastures can lead to a drastic reduction or local extinction of certain ant populations and compromise Cecropia-Azteca mutualistic relations.
PubDate: 2022-03-19
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- Bumblebee floral neighbors promote nectar robbing in a
hummingbird-pollinated plant species in Patagonia-
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Abstract: Abstract Nectar robbers are common cheaters of plant-pollinator mutualisms by making holes in flower tissues to attain floral rewards often without providing pollination service. Most studies have focused on the consequences of nectar robbing on plant reproduction, whereas the underlying drivers of spatiotemporal variation in nectar robbing have been comparatively less explored. We assessed variation in nectar robbing of Campsidium valdivianum, an endemic hummingbird-pollinated climber species from the temperate forests of Southern South America, which currently is subjected to nectar robbing by the alien short-tongued Bombus terrestris, and determined if this variation is related to characteristics of the floral neighborhood. We located plants of C. valdivianum and estimated the proportion of flowers with holes. We recorded the presence, identity and distance to the nearest bumblebee-pollinated plants with open flowers. Results showed that the proportion of robbed flowers in C. valdivianum increased almost seven times in the presence of bumblebee flowering plants in the neighborhood. No evidence was found that the proportion of robbed flowers differs between neighborhoods with Berberis darwinii only vs. B. darwinii and Cytisus scoparius, the co-flowering plant species typically visited by bumblebees during the study. Finally, the proportion of robbed flowers increased not only with the presence but also with the proximity of these bumblebee-pollinated plants. Our results suggest that floral neighborhoods attractive to bumblebees can operate as magnets, potentially increasing the intensity of nectar robbing on nearby hummingbird-pollinated species. This study provides novel insights into understanding spatio-temporal variation in nectar robbing.
PubDate: 2022-03-15
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- Comparative Pistacia vera leaf proteomics in response to herbivory of the
common pistachio psylla (Agonoscena pistaciae)-
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Abstract: Abstract Plants have evolved diverse mechanisms to cope with damages caused by insect herbivores. Proteomics can greatly contribute to the understanding of plant changes in response to herbivory. Here, two-dimensional polyacrylamide gel electrophoresis was used in a comparative proteomics approach to survey responses of pistachio seedlings to herbivory of the nymphal stages of the common pistachio psylla. Protein spots (~ 360) were reproducibly detected on each gel that led to the identification of 24 differentially expressed proteins via nano liquid chromatography tandem mass spectrometry (nLC-MS/MS). The identified proteins were involved in photosynthesis, glycolysis, signaling, protein folding, homeostasis, apoptotic processes, and stress response. Pyrophosphatase 6, controlled tumor protein, ferritin1, succinate dehydrogenase 1–1 were the proteins reported for the first time in response to herbivory. It seems that increased growth rate is a major strategy against herbivory stress of the psylla. The results of this study provide valuable information for understanding plants—herbivores interaction.
PubDate: 2022-03-14
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- Ultrastructural and morpho-anatomical features of rice plants confer
first-level of defense against yellow stem borer (Scirpophaga
incertulas Walker) infestation-
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Abstract: Yellow stem borer (YSB) is a serious pest of rice throughout the year in Asia and causes 40–50% yield loss. Screening genotypes and breeding resistant varieties are effective strategies for its management. The present study demonstrates the importance of ultrastructural and morpho-anatomical features of rice stem that confer resistance to YSB. A total of 188 rice genotypes were evaluated for dead heart and white ear damage of YSB. The crop booting stage of 113 genotypes coincided with peak YSB invasion. Forty-five days after transplanting (DAT), dead heart damage was recorded and 17 genotypes were found to be resistant. However, only one genotype, RG109, exhibited resistance based on white ear damage at crop maturity. Six genotypes selected based on dead heart damage were characterized for stem features using scanning electron microscopy, and their defense response against YSB was explored. Among the six genotypes, RG109 had a greater number of vascular bundles, density and width of silicified microstructures (SMS), and the density of trichomes. The elemental silica content inside and outside of the stem was mapped with SEM-supported energy-dispersive X-ray spectroscopy and found that RG109 had a higher silica content (17.85%) than the susceptible control, TN1 (1.12%), in the outer stem. Similarly, the adaxial side of the leaf blade and aerenchymatous region of the stem were studied extensively between the resistant (RG109) and susceptible (TN1) genotypes, further reiterating the differences in resistance level. Hence, surface morphological structures such as trichomes and SMS, their spatial distribution pattern and the elemental silica content hindered larval feeding behavior, which facilitates host plant-mediated YSB management in rice cultivation. Graphical abstract
PubDate: 2022-02-19
DOI: 10.1007/s11829-022-09890-4
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- Variation in foraging patterns as reflected by floral resources used by
male vs female bees of selected species at Badlands National Park, SD, USA
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Abstract: Abstract Female and male bees forage for different reasons: females provision nests with pollen appropriate for larval development and consume nectar for energy while males need only fuel their own energetic requirements. The expectation, therefore, is that females should visit fewer floral resource species than males, due to females’ focus on host plant species and their tie to the nest location. We used pollen collected from bees’ bodies and the flowers they were collected on to infer floral resource use in 2010–2012 at Badlands National Park, SD, USA. We collected bees on 24 1-ha plots centered on particular plant species. We compared number of floral species and families (1) associated with individual female and male bees (via generalized linear mixed models) and (2) accumulated by each sex (using rarefaction); and (3) effect of variation between sexes in plant-bee interactions via modularity analyses. Analyses were restricted to bee species with ≥ 5 individuals per sex. Contrary to expectation, female and male bees differed infrequently in the number of floral resources they had visited, both on single foraging bouts and collectively when accumulated across all males and females of a species. When males and females did differ, males visited fewer floral species than females. Generalist and specialist bee species did not differ markedly in floral resource use by females and males. When separated by sex, seven of eleven species occupied different modules than they did when analyzed as a species; most of the bee species were connectors, thus important for stability of the network during perturbations.
PubDate: 2022-02-11
DOI: 10.1007/s11829-021-09881-x
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- Local and systemic effect of azadirachtin on host choice and feeding
activity of Macrosiphum rosae on rose plants-
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Abstract: Abstract Many studies in the last decades addressed the antifeedant and repellent effects of neem (Azadirachta indica)-based pesticides on arthropod herbivores with azadirachtin as the leading active ingredient. However, results for aphids regarding repellence and feeding were often contradictory and mainly based on laboratory studies with self-made neem extracts in high concentrations. Moreover, no data are available on the presence of azadirachtin in the phloem of treated plants—the tissue that most aphids feed on. We investigated how the application of the commercial neem product NeemAzal-T/S onto only one plant half (upper or lower) affects nymphs of the aphid Macrosiphum rosae in clip cages on the untreated plant half. Results for aphid mortality indicate that active ingredients of NeemAzal-T/S are translocated both upwards and downwards in rose plants and that active ingredients are transported in the phloem. Furthermore, we investigated whether NeemAzal-T/S has a repellent or antifeedant effect on M. rosae. A choice test in the greenhouse as well as the quantification of honeydew excretion and electrical penetration graph analysis do not show differences in settling or feeding on untreated and NeemAzal-T/S-treated rose plants. Collectively, our data show that the effect of approved concentrations of NeemAzal-T/S on M. rosae is based on the toxicity after feeding on treated plants, not on starvation.
PubDate: 2022-02-07
DOI: 10.1007/s11829-022-09889-x
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- Incidence and preference of Frankliniella occidentalis (Thysanoptera:
Thripidae) to different rose cultivars-
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Abstract: Abstract Western flower thrips (WFT), Frankliniella occidentalis, is a major pest in rose crops worldwide. This pest causes considerable esthetic injuries to rose flowers, thus reducing their market value, which leads to economic losses. WFT attacks on rose cultivars are determined by environmental conditions and host–plant features such as resources supply, flower developmental stage, petal color, flower shape, and plant chemical cues. To recognize the possible role that chemical cues could play in WFT–rose interactions, WFT incidence in six commercial rose cultivars was studied in greenhouse plots for commercial growing, and WFT preference to these cultivars was evaluated in choice tests in daylight and darkness under laboratory conditions. Furthermore, the WFT responses to the cultivars’ flower odors were evaluated in a bioassay using a Y-tube olfactometer. Differences in the incidence of WFT between rose cultivars were observed in the field. Additionally, the choice tests showed a difference in WFT preference between rose cultivars in daylight conditions but not in darkness. For the six cultivars, WFT showed positive chemotactic responses to one cultivar and negative chemotactic response to two cultivars in Y-tube olfactometry bioassay. The different results found among the incidence in the field, the laboratory choice tests, and the Y-tube olfactometry bioassays, show that chemical cues alone cannot explain the behavioral responses of WFTs to different cultivars in the field.
PubDate: 2022-02-04
DOI: 10.1007/s11829-022-09886-0
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- Reciprocal interactions between aphids and arbuscular mycorrhizal fungi
across plant generations-
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Abstract: Abstract The conditions experienced by one plant generation can influence the growth of the offspring generation. These maternal effects can reduce performance of foliar-feeding insects, through accumulation of plant defences. Arbuscular mycorrhizal fungi (AMF) inhabit the roots of plants and are known to influence the performance of foliar-feeding insects. However, all published studies of the interactions between insects and AMF have taken place within one plant generation, but none across generations. Thus, in the present study, Senecio vulgaris plants were grown with or without aphids and AMF (termed ‘induction events’), and seeds from each treatment were used to grow plants experiencing that same treatment over four successive generations, all grown in identical environmental conditions. Naïve aphids were reared on Senecio plants whose parents had experienced 0, 1, 2 or 3 induction events. We found strong negative maternal effects of herbivory on aphid growth, which were not mitigated by the mycorrhiza. However, teneral weight and growth rate showed a gradual recovery; aphids reared on plants whose previous three generations suffered attack were similar in size to those at the beginning of the study. Herbivory had positive or negative effects on the mycorrhiza, dependent upon the number of previous generations suffering attack or having mycorrhizal associations. We conclude that the outcome of many insect plant fungal experiments is likely to have been influenced by and need to account for maternal effects of the parental plant’s growth conditions.
PubDate: 2022-02-01
DOI: 10.1007/s11829-021-09875-9
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- The introgression of resistance to Tuta absoluta in tomato based on
glandular trichomes-
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Abstract: Abstract Tomato (Solanum lycopersicum L.) is one of the most important and consumed vegetables worldwide both in fresh and processed form. Among the main pests, the South American tomato pinworm (Tuta absoluta Meyrick, Lepidoptera: Gelechiidae) stands out as one that causes great damage to its production. Control is based essentially on intensive chemical applications which increases the production cost, besides promoting ecological imbalances and possible health problems for consumers and farmers. Among the plant defense mechanisms against herbivores pests are the glandular trichomes and their secondary metabolites that together can be poisonous, repellent, or trap insects and other organisms. In order to develop a resistant cultivar to T. absoluta, we introgressed a trichome-based resistance trait from the wild tomato (Solanum pennellii) into cultivated tomato. The wild tomato has the type IV glandular trichomes, the major site of biosynthesis for acylsugars, which have been consistently linked to broad-spectrum resistance to herbivorous arthropods of tomato. The backcross genotypes (F2BC2) come from a cross between the species S. pennellii access LA-716 (donor genome with high acylsugar content) and the commercial cultivar S. lycopersicum cv. Redenção (background genome with low acylsugar content). Eight genotypes with high recovery of the background genome were selected to identify and quantify the glandular and non-glandular trichomes as well as to assess their resistance to the T. absoluta. Direct correlations between the acylsugar content, number of type IV glandular trichomes and resistance to the South American tomato pinworm were observed, indicating that the desired trait from S. pennellii is inherited throughout the backcrosses. Two groups were formed among the analyzed genotypes: high and low levels of acylsugars. In the high-level group, the higher acylsugar content led to a better control of the pinworm in a similar way to the wild parent (resistant). The overall analysis of our data shows that the genotypes RVTA-2010pl#232 and RVTA-2010pl#257 have the greatest potential to develop tomato lines with desirable commercial traits for the processing industry besides resistance to the South American tomato pinworm.
PubDate: 2022-02-01
DOI: 10.1007/s11829-021-09873-x
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- Population variation of Bemisia tabaci MED and MEAM1 species in an
agricultural landscape: the case of Çukurova plain-
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Abstract: Abstract Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is an economically important pest of agricultural crops. It is described as a species complex, among which MEAM1 (Middle East–Asia Minor 1) and MED (Mediterranean) are two of the most damaging and invasive species in the world. This study was conducted to determine the seasonal population variations of MEAM1 and MED species of B. tabaci from 2015 to 2018 in cotton fields of the Çukurova plain, Turkey. Whiteflies were sampled during the early season and late season from cotton fields located in six districts. A diagnostic microsatellite locus and PCR-RFLP methods were used to determine MED and MEAM1 species. Results showed that although its rate decreased over the years, MED was predominant over MEAM1 in cotton fields, with 60.9% of the total B. tabaci specimens determined as MED while 39.1% were MEAM1. The proportion of each species varied according to districts with the highest value of MED (100%) observed in inland districts. The species composition changed according to the season, and MEAM1 was found to be statistically higher in the late than the early season in the districts close to the Mediterranean Sea. The data showed that despite the closeness of the sampling areas, there was a habitat partitioning between MED and MEAM1 in the Çukurova plain. The crop pattern, migration, and climate were found to be important factors in the habitat partition. The results obtained in this study will help in the development of sustainable management strategies for these invasive species.
PubDate: 2022-01-31
DOI: 10.1007/s11829-021-09877-7
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- Host plant identity and condition shape phytophagous insect communities on
urban maple (Acer spp.) trees-
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Abstract: Abstract By mitigating the negative effects of urbanization, urban trees contribute significantly to the well-being of urban citizens. However, trees themselves are also exposed to urban stress that can influence tree condition and tree-herbivore interactions. Maple species (Acer spp.) are among the most commonly planted trees in urban areas throughout North America and Europe. Among these species, field, sycamore, and Norway maple are native to Europe, but tolerate environmental stress to varying degrees. Here, we compared the phytophagous insect communities in the canopy of these tree species in the city of Budapest, Hungary. We also examined the stress level [expressed as peroxidase (POD) enzyme activity], and physiological condition (expressed as degree of leaf necrosis and leaf fall) of the maple trees, and their relationship to herbivore abundance. We observed higher total abundance of phytophagous insects on field and sycamore maple compared to Norway maple. Most herbivorous species were associated with field maple, sycamore had the highest aphid densities, and Norway maple harbored the least specific phytophagous insect community. Field maple trees were in the best condition while Norway maple trees in the worst condition, i.e., with the highest proportion of necrotic leaf surface area. The super-abundant planthopper species, Metcalfa pruinosa positively affected the POD activity of trees, but did not influence their condition. On the contrary, M. pruinosa abundance was driven by tree condition, with higher numbers on healthier trees. Our findings suggest that the abundance of phytophagous insects in the canopy of maple trees is highly determined by tree condition, and in this study field maple had the highest and Norway maple the lowest tolerance for urban stress.
PubDate: 2022-01-21
DOI: 10.1007/s11829-022-09887-z
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- Impact of caterpillars and plant-parasitic nematodes on Chinese tallow
tree are more strongly affected by nematode density than by caterpillar
identity-
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Abstract: Abstract The relative importance of herbivore identity and density in determining the outcome of above-belowground herbivore interactions has not yet been fully explored. Here, we tested the effects of foliar insect identity (the specialist Gadirtha fusca vs. the generalist Spodoptera litura) on the number of root knots and the effects of nematode density on the performance of the two leaf herbivores. We found that plant-mediated interactions between the two caterpillars and the nematode were highly density-dependent. Herbivory by G. fusca facilitates the root-knot nematode Meloidogyne incognita, but only under the low density of nematodes. Conversely, infestation of M. incognita inhibited the performance of both caterpillars, which both grew smaller on nematode-infested plants and caused lower damage on plants under the low density of nematodes compared to plants with no nematodes. Both G. fusca or S. litura and the high density of nematodes herbivory either alone or in combination all greatly reduced plant growth and biomass of tallow compared to control plants with no herbivory. However, the combinative herbivory between the caterpillars (especially G. fusca) and the low density of nematodes exerted antagonistic effects on tallow tree that plant growth and biomass were similar or even higher than for control plants with no herbivory. Flavonoids and tannins varied among tissues and were also greatly influenced by nematode density. These results suggest that interactions among leaf and root organisms and their effects on the host plant appear to be more affected by root herbivore density than leaf herbivore identity.
PubDate: 2022-01-12
DOI: 10.1007/s11829-022-09883-3
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- Volatiles from eggplants infested by Aphis gossypii induce oviposition
behavior in the aphidophagous gall midge Aphidoletes aphidimyza-
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Abstract: Abstract Oviposition by aphidophagous predators is triggered by semiochemicals emitted from aphids and host plants, such as volatile chemicals from host plants infested by aphids and from honeydew and aphid alarm pheromones. Aphidoletes aphidimyza (Rondani) (Diptera: Cecidomyiidae) is a common, widely distributed aphidophagous predator that is used as a biological agent to control aphids in greenhouses. Previous work showed that a volatile chemical emitted from honeydew produced by Aphis gossypii Glover (Hemiptera: Aphididae) on eggplants (Solanum melongena L.) attracted adult female A. aphidimyza, and identified it as phenylacetaldehyde. There are no known oviposition stimulants for A. aphidimyza females and the function of herbivory-induced plant volatiles (HIPVs) produced by eggplants infested by A. gossypii is not clear. Therefore, this study investigated the effects of HIPVs from eggplants induced by A. gossypii infestation and volatile chemicals in honeydew produced by A. gossypii on the oviposition of A. aphidimyza in bioassay cages. We found that HIPVs from A. gossypii-infested eggplants-induced oviposition. Moreover, using gas chromatography coupled with mass spectrometry, we identified 6-methyl-5-hepten-2-one, nonanal, and decanal as the HIPVs from eggplants. A mixture of these three compounds-induced oviposition of significantly more eggs than the control, but fewer eggs than the eggplant–aphid complex. Honeydew did not induce oviposition of significantly more eggs than the control. In conclusion, oviposition by A. aphidimyza females was induced by HIPVs from A. gossypii-infested eggplants. But the statistical difference in the number of oviposited eggs between the honeydew treatment and uninfested eggplant was not significant.
PubDate: 2022-01-06
DOI: 10.1007/s11829-021-09882-w
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