Plant-insect Interactions Research Articles

Evaluation of cotton varieties resistant to Amrasca biguttula (Hemiptera: Ciccadelidae) in the Indonesian agroecosystem to mitigate climate change impacts

Climate change employs substantial effects on agroecosystems, particularly the dynamics between plants and herbivores. In response, the adoption of pest-resistant varieties has emerged as a critical strategy within agroecosystems, notably in Indonesia’s cotton Integrated Pest Management (IPM). This research focused on evaluating the response of five cotton lines, which adapted to the Indonesian agroecosystem, to the cotton leafhopper (Amrasca biguttula) as a mitigating measure to climate change. Two upland cotton varieties, Tamcot SP 37 (susceptible) and LRA 5166 (resistant), served as standards for susceptibility and resistance to leafhoppers. The study examined leaf morphological characters, specifically trichome density, known to act as oviposition deterrents for leafhopper females, indicative of non-preference resistance. Low damage scores and high leaf trichome density comparable to the resistant variety (LRA 5166) were indicators of notable field resistance in lines 06062/3/3 and 06062/3/4 against A. biguttula during observations that spanned 35 to 105 days post-planting. These findings highlight the potential of these lines as promising cotton varieties, marked by their resilience to A. biguttula, fostering sustainable cultivation practices that address climate change impacts. This study underscores the intricate dynamics between plant-insect interactions and resilience strategies within agroecosystems.

Plant-insect interactions of the Matzitzi and Tuzancoa formations during the Permian

In this work a quantitative and qualitative analysis of the herbivory in foliar elements of the Permian of Mexico was carried out, four functional feeding groups with low occurrence in the paleoflora of the Permian of Mexico were identified. All this data helps to better understand ecological relationships in past ecosystems. The new data come from two formations, Tuzancoa (state of Hidalgo) and Matzitzi (state of Puebla), from the lower and upper Permian respectively. A total of 827 specimens housed in the Paleontology Collection of the FES Zaragoza were analyzed. First, the fossils were identified taxonomically based on morphological characters. Subsequently, the damage observed on the leaf elements was qualitatively analyzed and described. The damages were assigns to functional feeding groups (FFG) and subsequently to damage types (DT). For the Tuzancoa Formation, a total of 241 fossils were identified and assigned to four orders and nine genera, the most abundant being Mariopteris and Taeniopteris. Regarding these, a total of three functional groups were identified: all of them on Comia leaves, margin feeding, hole feeding, and oviposition. Along with this, five types of damage were identified (DT02, DT04, DT05, DT15 and DT101). Another important point to mention is the low percentage of damage frequency that is around 0.82%. For the Matzitzi Formation, a total of 586 fossils were identified, assigned to 11 orders and 25 genera, the best represented being the ferns of the genus Asterotheca and the leaf incertae sedis Velascophyllum. Two functional groups were identified, hole feeding and galling. The first functional group was identified on a Gigantonoclea leaf and belongs to Dt05 group. On the other hand, the galls have a greater diversity of shapes and sizes (DT49, DT117, DT70, DT259 and DT266); These damages are located on foliar elements of Velascophyllum, Cordaites, Calamites, Asterotheca and Diplazites. Once again, a low percentage of damage frequency is observed, around 2.5%. Herbivory studies in Mexico are still in an early stage and it is necessary to continue with this line of research to have a better understanding of plant-insect interactions in late Paleozoic ecosystems.

Deciphering plant insect interactions from the Bruay Formation (Carboniferous, Nord / Pas-De-Calais coal basin, France)

Deciphering plant insect interactions from the Bruay Formation (Carboniferous, Nord / Pas-De-Calais coal basin, France)

Intraspecific chemical variation of Tanacetum vulgare affects plant growth and reproductive traits in field plant communities.

The study investigated the impact of intraspecific plant chemodiversity on plant growth and reproductive traits at both the plant and plot levels. It also aimed to understand how chemodiversity at stand level affects ecosystem functioning and plant-plant interactions. We describe a biodiversity experiment in which we manipulated intraspecific plant chemodiversity at the plot level using six different chemotypes of common tansy (Tanacetum vulgare L., Asteraceae). We tested the effects of chemotype identity and plot-level chemotype richness on plant growth and reproductive traits and plot-level headspace emissions. The study found that plant chemotypes differed in growth and reproductive traits and that traits were affected by the chemotype richness of the plots. Although morphological differences among chemotypes became less pronounced over time, reproductive phenology patterns persisted. Plot-level trait means were also affected by the presence or absence of certain chemotypes in a plot, and the direction of the effect depended on the specific chemotype. However, chemotype richness did not lead to overyielding effects. Lastly, chemotype blends released from plant communities were neither richer nor more diverse with increasing plot-level chemotype richness, but became more dissimilar as they became more dissimilar in their leaf terpenoid profiles. We found that intraspecific plant chemodiversity is crucial in plant-plant interactions. We also found that the effects of chemodiversity on plant growth and reproductive traits were complex and varied depending on the chemotype richness of the plots. This long-term field experiment will allow further investigation into plant-insect interactions and insect community assembly in response to intraspecific chemodiversity.

Phenylalanine treatment induces tomato resistance to Tuta absoluta via increased accumulation of benzenoid/phenylpropanoid volatiles serving as defense signals.

Tuta absoluta ("leafminer"), is a major pest of tomato crops worldwide. Controlling this insect is difficult due to its efficient infestation, rapid proliferation, and resilience to changing weather conditions. Furthermore, chemical pesticides have only a short-term effect due to rapid development of T. absoluta strains. Here, we show that a variety of tomato cultivars, treated with external phenylalanine solutions exhibit high resistance to T. absoluta, under both greenhouse and open field conditions, at different locations. A large-scale metabolomic study revealed that tomato leaves absorb and metabolize externally given Phe efficiently, resulting in a change in their volatile profile, and repellence of T. absoluta moths. The change in the volatile profile is due to an increase in three phenylalanine-derived benzenoid phenylpropanoid volatiles (BPVs), benzaldehyde, phenylacetaldehyde, and 2-phenylethanol. This treatment had no effect on terpenes and green leaf volatiles, known to contribute to the fight against insects. Phe-treated plants also increased the resistance of neighboring non-treated plants. RNAseq analysis of the neighboring non-treated plants revealed an exclusive upregulation of genes, with enrichment of genes related to the plant immune response system. Exposure of tomato plants to either benzaldehyde, phenylacetaldehyde, or 2-phenylethanol, resulted in induction of genes related to the plant immune system that were also induced due to neighboring Phe-treated plants. We suggest a novel role of phenylalanine-derived BPVs as mediators of plant-insect interactions, acting as inducers of the plant defense mechanisms.

Gut microbiota metagenomics and mediation of phenol degradation in Bactrocera minax (Diptera, Tephritidae).

Gut microbiota mediating insect-plant interactions have many manifestations, either by provisioning missing nutrients, or by overcoming plant defensive reactions. However, the mechanism by which gut microbiota empower insects to survive by overcoming a variety of plant secondary metabolites remains largely unknown. Bactrocera minax larvae develop in immature citrus fruits, which present numerous phenolic compounds that challenge the larvae. To explore the role of gut microbes in host use and adaptability, we uncovered the mechanisms of phenol degradation by gut microbes using metagenomic and metatranscriptomic analyses, and verified the degradation ability of isolated and cultured bacteria. Research on this subject can help develop potential strain for the environmental friendly pest management operations. We demonstrated the ability of gut microbes in B. minax larvae to degrade phenols in unripe citrus. After antibiotic treatment, coniferyl alcohol and coumaric aldehyde significantly reduced the survival rate, body length and body weight of the larvae. The metagenomic and metatranscriptomic analyses in B. minax provided evidence for the presence of genes in bacteria and the related pathway involved in phenol degradation. Among them, Enterococcus faecalis and Serratia marcescens, isolated from the gut of B. minax larvae, played critical roles in phenol degradation. Furthermore, supplementation of E. faecalis and S. marcescens in artificial diets containing coniferyl alcohol and coumaric aldehyde increased the survival rate of larvae. In summary, our results provided the first comprehensive analysis of gut bacterial communities by high-throughput sequencing and elucidated the role of bacteria in phenol degradation in B. minax, which shed light on the mechanism underlying specialist insect adaption to host secondary metabolites via gut bacteria. © 2024 Society of Chemical Industry.

Effects of plant leaf traits, abundance and phylogeny on differentiation of herbivorous insect assemblages in Mediterranean mixed forest

AbstractHerbivorous insect assemblages are functionally diverse, with each species exploiting plant tissues in different ways. Availability and palatability of plant tissues influence the diversity and composition of herbivorous insect assemblages. However, few studies have compared herbivorous insect assemblages and their ecological correlates across multiple plant species within the same plant community. Here, we sampled insect assemblages from the canopies of 1060 plants belonging to 36 woody species in two mixed Mediterranean forest stands. 401 insect species were classified as herbivores and grouped into sucker or chewer guilds. We explored differences in the diversity and composition of each insect guild across plant species, and tested their relationships with plant leaf traits, abundance or phylogeny, and explored whether the structures of plant-herbivorous insect networks depended on any of the studied plant traits. Plant identity accounted for the highest proportion of variation in the composition of each insect guild. Plant species abundance showed a positive effect on both insect guilds’ diversity. Suckers’ diversity was higher in plant species with deciduous leaves and low SLA, while the composition was more similar between phylogenetically closer plant species. Chewers diversity increased with the leaf area, while plants with similar LA, leaf nitrogen, SLA and distinct leaf habit showed more similar assemblages. Similarly, closely related angiosperms showed similar chewer assemblages. Plant–insect interaction networks present a modular structure, in which plants belonging to the same module tend to be related and share more sucker species. We add to the evidence supporting the role of plant species features as filters for structuring their associated herbivore insect assemblages.

Guidelines for conducting, analyzing, and interpreting electrical penetration graph (EPG) experiments on herbivorous piercing–sucking insects

AbstractThe electrical penetration graph (EPG) allows researchers to obtain information on the feeding behavior of herbivorous piercing–sucking insects, mostly Hemiptera. Guidelines are proposed for designing and conducting EPG experiments on insect–plant interactions, and for analyzing and interpreting the data. Several statistical issues common in EPG experiments are discussed. Pre‐recording insect handling, wiring, and being tethered can affect feeding behavior and recommendations are made to minimize such stresses. Recording duration can have a large effect on some variables and interpretation of the data. The pros and cons of long vs. short recording duration are discussed, and suggestions are made for reconciling these conflicting concerns. Replicates lacking a specific waveform pose problems for analyzing variables associated with that waveform. Proper ways for handling these replicates when analyzing data are discussed. The waveform in progress when the recording ends will be terminated before it would naturally end; consequently, its duration will be artificially short (truncated). This creates a problem for calculating mean or median duration of waveform periods (a waveform period is a single occurrence of the waveform), especially for waveforms that tend to occur relatively few times during a recording and in long periods, such as waveforms E2 and G (phloem and xylem sap ingestion for aphids) or Xi (xylem sap ingestion for xylem feeders). Based on a detailed analysis (see the supporting information), guidance is given on how to calculate mean and median duration of waveform periods when the last period is truncated. A modified experimental design is suggested to avoid the problem of truncated waveform periods. Most EPG variables are interdependent, and their values can affect one another. This interdependence should be considered when drawing conclusions from the data. In studies on plant resistance against vascular sap‐feeders, variables that are associated with resistance encountered during the penetration route to the vascular tissue and those encountered in the vascular tissue are discussed.

Rapid on‐ground assessment after the 2019–2020 megafires reveals new information on rare and threatened plants in northern New South Wales, Australia

AbstractLack of ecological knowledge is a major challenge for effective conservation of threatened plant species in Australia as disturbance events, such as wildfire, increase in frequency and magnitude. Rapid on‐ground surveys are increasingly important to inform recovery strategies for rare and threatened plants in response to extreme wildfire events, yet resources are rarely available to deploy time‐sensitive surveys. Here, we utilize a rapid on‐ground survey and monitoring program to document basic biological and ecological information for 21 rare and threatened plant species from the New England bioregion in northern New South Wales, which were affected by the catastrophic 2019–2020 megafires. Our results fill an important knowledge gap of ecology, population size, distribution and response to fire for these taxa, document for the first time a species distribution pattern within the Torrington State Conservation Area and reveal previously undocumented plant–insect interactions for nine species, including likely pollination of Persoonia terminalis ssp. terminalis and Monotaxis macrophylla by native bee (Hymenoptera) and fly (Diptera) species. Our findings reveal that two species (Cassinia heleniae and Hakea macrorrhyncha) have scarce distribution and low population sizes, despite neither having a conservation listing and their threat status should be urgently assessed. Simple rapid on‐ground surveys can be more cost effective for delivering long‐term conservation outcomes for rare and threatened taxa and we advocate that future funding and prioritisation processes must support the immediate delivery of such surveys in response to disturbance events.

Enhanced parasitisation of caterpillars and aphids on field‐grown Brassica oleracea plants upon soil amendment with insect exuviae

Abstract Multitrophic plant–insect interactions are mediated by plant volatiles. The emission of herbivore‐induced plant volatiles is influenced by environmental conditions, such as soil microbes and nutrient composition, with consequences for above‐ground trophic interactions. Here, we investigated whether insect exuviae in the soil alter the plant's volatile blend and attraction of parasitoids in the laboratory and whether this attraction also occurs in the field. We studied the effects of soil amendment with exuviae originating from three insect species, Tenebrio molitor, Acheta domesticus and Hermetia illucens, on the proportion of parasitised Plutella xylostella caterpillars and Brevicoryne brassicae aphids in the field in three consecutive years. In the laboratory, we collected and analysed the volatile blend of amended plants infested with caterpillars or aphids. The attraction of the parasitoids Diadegma semiclausum and Diaeretiella rapae, respectively, towards these volatile blends was assessed in an olfactometer. Our study shows that insect exuviae‐amended soil enhanced the proportion of parasitised herbivores of two species in the field. Relative amounts of several components of the plant volatile blend were affected by soil amendment. Soil amendment with Acheta domesticus or Tenebrio molitor exuviae resulted in an increased attraction of the two parasitoid species in the olfactometer. Soil amendment with insect exuviae altered the plant volatile blend leading to enhanced attraction of parasitoids in laboratory assays. These effects were sustained under the complex and variable biotic and abiotic conditions in the field. Our results underline the importance of belowground processes, such as the decomposition of insect exuviae, on aboveground volatile‐mediated multitrophic interactions. Read the free Plain Language Summary for this article on the Journal blog.

Interactions of Opuntia ficus-indica with Dactylopius coccus and D. opuntiae (Hemiptera: Dactylopiidae) through the Study of Their Volatile Compounds.

Opuntia ficus-indica has always interacted with many phytophagous insects; two of them are Dactylopius coccus and D. opuntiae. Fine cochineal (D. coccus) is produced to extract carminic acid, and D. opuntiae, or wild cochineal, is an invasive pest of O. ficus-indica in more than 20 countries around the world. Despite the economic and environmental relevance of this cactus, D. opuntiae, and D. coccus, there are few studies that have explored volatile organic compounds (VOCs) derived from the plant-insect interaction. The aim of this work was to determine the VOCs produced by D. coccus and D. opuntiae and to identify different VOCs in cladodes infested by each Dactylopius species. The VOCs (essential oils) were obtained by hydrodistillation and identified by GC-MS. A total of 66 VOCs from both Dactylopius species were identified, and 125 from the Esmeralda and Rojo Pelón cultivars infested by D. coccus and D. opuntiae, respectively, were determined. Differential VOC production due to infestation by each Dactylopius species was also found. Some changes in methyl salicylate, terpenes such as linalool, or the alcohol p-vinylguaiacol were related to Dactylopius feeding on the cladodes of their respective cultivars. Changes in these VOCs and their probable role in plant defense mechanisms should receive more attention because this knowledge could improve D. coccus rearing or its inclusion in breeding programs for D. opuntiae control in regions where it is a key pest of O. ficus-indica.

The Hidden World of Insect-Plant Interactions: a review

This review examines the hidden world of plant-insect interactions by emphasizing on the sensory perception and behavior of phytophagous insects, nutritional influence on insect reproduction, host plant resistance, Insects, weed and crop interaction, Insect pollinator plant interaction, tri-trophic interaction, and insect biotechnology. It explores how insects use sensory cues to forage for food, find mates, perceive dangers, and navigate their environment. It also examines the influence of host plants on insect behavior and the use of chemical cues for communication. The potential use of semio-chemicals in pest management for sustainable agriculture is highlighted. Nutritional factors and their impact on insect reproductive success are also discussed, emphasizing the need for balanced diets. The different categories of host plant resistance and their effects on insects are examined. The interdependent relationships between insects, plants, and weeds in agricultural ecosystems are explored, with a focus on the role of insect pollinators. The decline of insect pollinators and the importance of studying them are emphasized. The importance of tri-trophic interactions in maintaining ecological balance and biodiversity is discussed. Moreover, the role of biotechnological techniques like genomics, proteomics, transcriptomics, and epigenetics in understanding insect plant interactions as well as developing insect pest control strategies is discussed. The potential use of natural products produced by plants in environmentally friendly pest control methods is also examined. Overall, this review provides a comprehensive exploration of insect-plant interactions and the potential for sustainable pest control methods.

Assessing Pollinator Assembly And Efficacy Across Species Ranges In The Genus Triodanis (Campanulaceae)

Plant-insect interactions are a key topic in evolutionary ecology, especially in the face of anthropogenic changes which threaten to disrupt these mutualisms. An in-depth pollinator survey for species in the genus Triodanis is performed here for the first time, with sampling covering four species and spanning a large portion of their geographic ranges (i.e., four U.S. states). All species in the genus exhibit dimorphic cleistogamy with variability in allocation to open (chasmogamous) flowers among populations and taxa. The genus Triodanis, therefore, provides an opportunity for understanding possible associations between pollinator assemblies and variation in species, breeding system, and geography. To assess these relationships, we sampled four species or subspecies of Triodanis at eight field sites in four states. Sampling encompassed a broad area across the Midwestern U.S. and Texas, and across a gradient of anthropogenically disturbed habitats. We found that for species of Triodanis: 1) small bee and fly generalist pollinators showed some floral constancy during feeding bouts but did not differentiate between species, 2) pollinator community was less diverse and abundant in highly degraded habitats, 3) while allocation to open flowers varied among species and populations, we found no association between breeding system (or species) on pollinator identity or abundance. This study represents the first in-depth survey of pollinator visitors of Triodanis and serves as foundational knowledge about the natural history of this group, provides resolution for members of Campanulaceae exhibiting floral traits of generalist hosts, and important documentation of plant-insect interactions in an era of ongoing anthropogenic changes.

Climate warming impacts chewing Spodoptera litura negatively but sucking Corythucha marmorata positively on native Solidago canadensis

Insect-plant interactions are among importantly ecological processes, and rapid environmental changes such as temperature and resource fluctuations can disrupt long-standing insect-plant interactions. While individual impacts of climate warming, atmospheric nitrogen (N) deposition, and plant provenance on insect-plant interactions are well studied, their joint effects on insect-plant interactions are less explored in ecologically realistic settings. To this end, we performed five experiments with native and invasive Solidago canadensis populations from home and introduced ranges and two insect herbivores (leaf-chewing Spodoptera litura and sap-sucking Corythucha marmorata) in the context of climate warming and N deposition. We determined leaf defensive traits, feeding preference, and insect growth and development, and quantified the possible associations among climate change, host-plant traits, and insect performance with structural equation modeling. First, native S. canadensis populations experienced higher damage by S. litura but lower damage by C. marmorata than invasive S. canadensis populations in the ambient environment. Second, warming decreased the leaf consumption, growth, and survival of S. litura on native S. canadensis populations, but did not affect these traits on invasive S. canadensis populations; warming increased the number of C. marmorata on native S. canadensis populations via direct facilitation, but decreased that on invasive S. canadensis populations via indirect suppression. Third, N addition enhanced the survival of S. litura on native S. canadensis populations, and its feeding preference and leaf consumption on invasive S. canadensis populations. Finally, warming plus N addition exhibited non-additive effects on insect-plant interactions. Based on these results, we tentatively conclude that climate warming could have contrasting effects on insect-plant interactions depending on host-plant provenance and that the effects of atmospheric N deposition on insects might be relatively weak compared to climate warming. Future studies should focus on the molecular mechanisms underlying these different patterns.

Morphometric analysis of wild potato leaves

To catalog and promote the conservation and use of crop wild relatives, comprehensive phenotypic and genotypic information must be available. Plant genotyping has the power to resolve the phylogenetic relationships between crop wild relatives, quantify genetic diversity, and identify marker-trait associations for expedited molecular breeding. However, access to cost-effective genotyping strategies is often limited in underutilized crops and crop wild relatives. Potato landraces and wild species, distributed throughout Central and South America, exhibit remarkable phenotypic diversity and are an invaluable source of resistance to pests and pathogens. Unfortunately, very limited information is available for these germplasm resources, particularly regarding phenotypic diversity and potential use as trait donors. In this work, more than 150 accessions corresponding to 12 species of wild and cultivated potatoes, collected from different sites across the American continent, were analyzed using computer vision and morphometric methods to evaluate leaf size and shape. In total, more than 1100 leaves and leaflets were processed and analyzed for nine traits related to size, shape, and color. The results produced in this study provided a visual depiction of the extensive variability among potato wild species and enabled a precise quantification of leaf phenotypic differences, including shape, color, area, perimeter, length, width, aspect ratio, convexity, and circularity. We also discussed the application and utility of inexpensive but comprehensive morphometric approaches to catalog and study the diversity of crop wild relatives. Finally, this study provided insights for further experimental research looking into the potential role of leaf size and shape variation in plant–insect interactions, agronomic productivity, and adaptation.

Salivary proteins potentially derived from horizontal gene transfer are critical for salivary sheath formation and other feeding processes

Herbivorous insects employ an array of salivary proteins to aid feeding. However, the mechanisms behind the recruitment and evolution of these genes to mediate plant-insect interactions remain poorly understood. Here, we report a potential horizontal gene transfer (HGT) event from bacteria to an ancestral bug of Eutrichophora. The acquired genes subsequently underwent duplications and evolved through co-option. We annotated them as horizontal-transferred, Eutrichophora-specific salivary protein (HESPs) according to their origin and function. In Riptortus pedestris (Coreoidea), all nine HESPs are secreted into plants during feeding. The RpHESP4 to RpHESP8 are recently duplicated and found to be indispensable for salivary sheath formation. Silencing of RpHESP4-8 increases the difficulty of R. pedestris in probing the soybean, and the treated insects display a decreased survivability. Although silencing the other RpHESPs does not affect the salivary sheath formation, negative effects are also observed. In Pyrrhocoris apterus (Pyrrhocoroidea), five out of six PaHESPs are secretory salivary proteins, with PaHESP3 being critical for insect survival. The PaHESP5, while important for insects, no longer functions as a salivary protein. Our results provide insight into the potential origin of insect saliva and shed light on the evolution of salivary proteins.

GC-MS-based Metabolomics Unravels Metabolites across Larval Development and Diapause of a Specialist Insect.

Plant-insect interactions are a driving force into ecosystem evolution and community dynamics. Many insect herbivores enter diapause, a developmental arrest stage in anticipation of adverse conditions, to survive and thrive through seasonal changes. Herein, we investigated the roles of medium- to non-polar metabolites during larval development and diapause in a specialist insect herbivore, Chlosyne lacinia, reared on Aldama robusta leaves. Varying metabolites were determined using gas chromatography-mass spectrometry (GC-MS)-based metabolomics. Sesquiterpenes and steroids were the main metabolites putatively identified in A. robusta leaves, whereas C. lacinia caterpillars were characterized by triterpenes, steroids, fatty acids, and long-chain alkanes. We found out that C. lacinia caterpillars biosynthesized most of the identified steroids and fatty acids from plant-derived ingested metabolites, as well as all triterpenes and long-chain alkanes. Steroids, fatty acids, and long-chain alkanes were detected across all C. lacinia instars and in diapausing caterpillars. Sesquiterpenes and triterpenes were also detected across larval development, yet they were not detected in diapausing caterpillars, which suggested that these metabolites were converted to other molecules prior to the diapause stage. Our findings shed light on the chemical content variation across C. lacinia development and diapause, providing insights into the roles of metabolites in plant-insect interactions.

Rich specialized insect damage on Pliocene leaves from the Mahuadanr Valley (India) growing under a warm climate with weak seasonality.

Plant-insect interactions play a crucial role in shaping terrestrial ecosystems, influencing abundance and distribution of plant species. In the present study, we investigated leaf-mining patterns on fossil leaves from Pliocene strata of the Mahuadanr Valley, Jharkhand, eastern India, deposited under a seasonal tropical climate, and reported complex interactions between plants and insects. We identified 11 distinct mining morphotypes. These morphotypes were mainly found on Dipterocarpaceae, Fabaceae, Lauraceae, and Moraceae; similar mining traces were also observed in the contemporary vegetation surrounding the fossil site. Although mining richness was relatively high, only 2.6% of all leaves in the fossil assemblage were mined. We compared mining richness and abundance values with previously reported values for galling. While richness was slightly lower for galling, almost 50% of all fossil leaves were galled. A literature survey on mining and galling patterns in modern vegetation suggests that there is no global explanation for richness of mining or gall-inducing insects. Thus, low nutrient availability in the ancient forest, dominance of semideciduous leaves with hard texture, and different habitats in the same forest ecosystem, such as well-drained forests and riparian stands, may all have favored different types of specialized plant-insect interactions.

Unveiling the Slippery Secrets of Saliva: Effector Proteins of Phloem-Feeding Insects.

Phloem-feeding insects include many important agricultural pests that cause crop damage globally, either through feeding-related damage or upon transmission of viruses and microbes that cause plant diseases. With genetic crop resistances being limited to most of these pests, control relies on insecticides, which are costly and damaging to the environment and to which insects can develop resistance. Like other plant parasites, phloem-feeding insects deliver effectors inside their host plants to promote susceptibility, most likely by a combination of suppressing immunity and promoting nutrient availability. The recent emergence of the effector paradigm in plant-insect interactions is highlighted by increasing availability of effector repertoires for a range of species and a broadening of our knowledge concerning effector functions. Here, we focus on recent progress made toward identification of effector repertoires from phloem-feeding insects and developments in effector biology that will advance functional characterization studies. Importantly, identification of effector activities from herbivorous insects promises to provide new avenues toward development of crop protection strategies. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.

Nontarget impacts of neonicotinoids on nectar-inhabiting microbes.

Plant-systemic neonicotinoid (NN) insecticides can exert non-target impacts on organisms like beneficial insects and soil microbes. NNs can affect plant microbiomes, but we know little about their effects on microbial communities that mediate plant-insect interactions, including nectar-inhabiting microbes (NIMs). Here we employed two approaches to assess the impacts of NN exposure on several NIM taxa. First, we assayed the in vitro effects of six NN compounds on NIM growth using plate assays. Second, we inoculated a standardised NIM community into the nectar of NN-treated canola (Brassica napus) and assessed microbial survival and growth after 24 h. With few exceptions, in vitro NN exposure tended to decrease bacterial growth metrics. However, themagnitude of the decrease and the NN concentrations at which effects were observed varied substantially across bacteria. Yeasts showed no consistent in vitro response to NNs. In nectar, we saw no effects of NN treatment on NIM community metrics. Rather, NIM abundance and diversity responded to inherent plant qualities like nectar volume. In conclusion, we found no evidence that NIMs respond to field-relevant NN levels in nectar within 24 h, but our study suggests that context, specifically assay methods, time and plant traits, is important in assaying the effects of NNs on microbial communities.