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759 results for “Plant–plant interactions”
Plant traits shape soil legacy effects on individual plant-insect interactions
<p>Plant-mediated soil legacy effects can be important determinants of the performance of plants and their aboveground insect herbivores, but so far, soil legacy effects on plant-insect interactions have been tested for only a limited number of host plant species and soils. Here, we tested the performance of a polyphagous aboveground herbivore, caterpillars of the cabbage moth, <i>Mamestra brassicae</i> on twelve host plant species that were grown on a set of soils conditioned by each of these twelve species. We tested how growth rate (fast- or slow-growing) and functional type (grass or forb) of the plant species that conditioned the soil and of the responding host plant species growing in those soils affect the response of insect herbivores to conditioned soils. Our results show that plants and insect herbivores had lower biomass in soils that were conditioned by fast-growing forbs than in soils conditioned by slow-growing forbs. In soils conditioned by grasses, growth rate of the conditioning plant had the opposite effect, i.e., plants and herbivores had higher biomass in soils conditioned by fast-growing grasses, than in soils conditioned by slow-growing grasses. <a name="_Hlk21962191">We show that the response of aboveground insects to soil legacy effects is strongly positively correlated with the response of the host plant species, indicating that plant vigour may explain these relationships. </a>We provide evidence that soil communities can play an important role in shaping plant-insect interactions aboveground. Our results further emphasize the important and interactive role of the conditioning and the response plant in mediating soil-plant-insect interactions.</p>
Data from: Bottom-up effects of host-plant species diversity and top-down effects of ants interactively increase plant performance
While plant diversity is well known to increase primary productivity, whether these bottom-up effects are enhanced by reciprocal top-down effects from the third trophic level is unknown. We studied whether pine tree species diversity, aphid-tending ants and their interaction determined plant performance and arthropod community structure. Plant diversity had a positive effect on aphids, but only in the presence of mutualistic ants, leading to threefold greater number of both groups in the tri-specific cultures than in monocultures. Plant diversity increased ant abundance not only by increasing aphid number, but also by increasing ant recruitment per aphid. The positive effect of diversity on ants in turn cascaded down to increase plant performance; diversity increased plant growth (but not biomass), and this effect was stronger in the presence of ants. Consequently, bottom-up effects of diversity within the same genus and guild of plants and top-down effects from the third trophic level (predatory ants) interactively increased plant performance.
Data from: Plant fertilization interacts with life history: variation in stoichiometry and performance in nettle-feeding butterflies.
Variation in food stoichiometry affects individual performance and population dynamics, but it is also likely that species with different life histories should differ in their sensitivity to food stoichiometry. To address this question, we investigated the ability of the three nettle-feeding butterflies (Aglais urticae, Polygonia c-album, and Aglais io) to respond adaptively to induced variation in plant stoichiometry in terms of larval performance. We hypothesized that variation in larval performance between plant fertilization treatments should be functionally linked to species differences in host plant specificity. We found species-specific differences in larval performance between plant fertilization treatments that could not be explained by nutrient limitation. We showed a clear evidence of a positive correlation between food stoichiometry and development time to pupal stage and pupal mass in A. urticae. The other two species showed a more complex response. Our results partly supported our prediction that host plant specificity affects larval sensitivity to food stoichiometry. However, we suggest that most of the differences observed may instead be explained by differences in voltinism (number of generations per year). We believe that the potential of some species to respond adaptively to variation in plant nutrient content needs further attention in the face of increased eutrophication due to nutrient leakage from human activities.
Data from: Ants at plant wounds – a little-known trophic interaction with evolutionary implications for ant-plant interactions
Extrafloral nectaries (EFNs) allow plants to engage in mutualisms with ants preventing herbivory in exchange for food. EFNs occur scattered through the plant phylogeny and likely evolved independently from herbivore-created wounds subsequently visited by ants collecting leaked sap. Records of wound-feeding ants are, however, anecdotal. By surveying 38,000 trees from 40 species, we conduct the first quantitative ecological study of this overlooked behavior. Ant-wound interactions were widespread (0.5% of tree individuals) and occurred on 23 tree species. Interaction networks were opportunistic, closely resembling ant-EFNs networks. Fagaceae, a family lacking EFNs, were strongly overrepresented. For Fagaceae, ant occurrence at wounds correlated with species-level leaf damage, potentially indicating that wounds may attract mutualistic ants, supporting the hypothesis of ant-tended wounds as precursors of ant-EFNs mutualisms. Given the commonness of herbivore wounds, wound sap as steadily available food source might furthermore help to explain the overwhelming abundance of ants in (sub)tropical forest canopies.
Data from: Functional dissimilarity, not phylogenetic relatedness, determines interspecific interactions among plants in the Tibetan alpine meadows
The hypotheses suggesting that the nature and strength of species interactions should be determined by phylogenetic relatedness have important implications for the understanding of community structure. However, to date, there is limited empirical evidence to support them. At least two basic conditions need to be met in order to expect species interactions to be determined by evolutionary relatedness: a phylogenetic signal in the traits involved in the interactions and changes in the interactions as species are more ecologically similar. Here, we report results of a removal experiment in the Chinese Tibetan plateau in which we directly assessed if the nature and/or strength of interactions among twelve alpine meadow plant species were influenced by their phylogenetic relatedness and/or their functional dissimilarity. For each plant species, we compared its biomass production when grown alone to its biomass in presence of another species and used it as a measure of species interactions. Competition between pairs of species was more frequent than facilitation, with 60% of interactions resulting in plants producing less biomass when a second species was present. We found no effect of phylogenetic relatedness on the prevalence or intensity of competition or facilitation, presumably as none of the studied traits showed phylogenetic signal. Functional dissimilarity based on maximum plant height alone was the best predictor of both the prevalence and strength of competition and facilitation, followed by functional dissimilarity using all five functional traits. Our results pinpoint the limited capacity of phylogenetic relatedness as predictor of species interactions; underlining the limitations of using phylogenetic dispersion patterns to infer mechanisms of community assembly. On the contrary, when the right functional traits are used, functional dissimilarity among species can predict both the nature and strength of their interactions; accentuating the relevance of trait-based approaches in community ecology research.
Data from: Direct and indirect transgenerational effects alter plant-herbivore interactions
Theory suggests that environmental effects with transgenerational consequences, including rapid evolution and maternal effects, may affect the outcome of ecological interactions. However, indirect effects occur when interactions between two species are altered by the presence of a third species, and make the consequences of transgenerational effects difficult to predict. We manipulated the presence of insect herbivores and the competitor Medicago polymorpha in replicated Lotus wrangelianus populations. After one generation, we used seeds from the surviving Lotus to initiate a reciprocal transplant experiment to measure how transgenerational effects altered ecological interactions between Lotus, Medicago, and insect herbivores. Herbivore leaf damage and Lotus fecundity were dependent on both parental and offspring environmental conditions. The presence of insect herbivores or Medicago in the parental environment resulted in transgenerational changes in herbivore resistance, but these effects were non-additive, as a result of indirect effects in the parental environment. Indirect transgenerational effects interacted with more immediate ecological indirect effects on Lotus fecundity. These results suggest that explanations of ecological patterns require an understanding of transgenerational effects and that these effects may be difficult to predict in species-rich, natural communities where indirect effects are prevalent.
Data from: Intraspecific variation in herbivore-induced plant volatiles influences the spatial range of plant-parasitoid interactions
Chemical information influences the behaviour of many animals, thus affecting species interactions. Many animals forage for resources that are heterogeneously distributed in space and time, and have evolved foraging behaviour that utilizes information related to these resources. Herbivore-induced plant volatiles (HIPVs), emitted by plants upon herbivore attack, provide information on herbivory to various animal species, including parasitoids. Little is known about the spatial scale at which plants attract parasitoids via HIPVs under field conditions and how intraspecific variation in HIPV emission affects this spatial scale. Here, we investigated the spatial scale of parasitoid attraction to two cabbage accessions that differ in relative preference of the parasitoid Cotesia glomerata when plants were damaged by Pieris brassicae caterpillars. Parasitoids were released in a field experiment with plants at distances of up to 60 m from the release site using intervals between plants of 10 or 20 m to assess parasitism rates over time and distance. Additionally, we observed host-location behaviour of parasitoids in detail in a semi-field tent experiment with plant spacing up to 8 m. Plant accession strongly affected successful host location in field set-ups with 10 or 20 m intervals between plants. In the semi-field set-up, plant finding success by parasitoids decreased with increasing plant spacing, differed between plant accessions, and was higher for host-infested plants than for uninfested plants. We demonstrate that parasitoids can be attracted to herbivore-infested plants over large distances (10m or 20m) in the field, and that stronger plant attractiveness via HIPVs increases this distance (up to at least 20m). Our study indicates that variation in plant traits can affect attraction distance, movement patterns of parasitoids, and ultimately spatial patterns of plant-insect interactions. It is therefore important to consider plant-trait variation in HIPVs when studying animal foraging behaviour and multi-trophic interactions in a spatial context.
Data from: Extreme drought stress shifts net facilitation to neutral interactions between shrubs and sub-canopy plants in an arid desert
The stress gradient hypothesis (SGH) predicts that the importance or intensity of competition and facilitation will change inversely along abiotic stress gradients. It was originally postulated that increasing environmental stress can induce a monotonic increase in facilitation. However, more recent models predicted that the relationship between severity and interaction exhibits a hump-shaped pattern, in which positive interactions prevail under moderate stress but decline at the extreme ends of stress gradients. In the present study, we conducted a field experiment along a temporal rainfall gradient for five consecutive years, in order to investigate interactions in a shrub-herbaceous plant community at the southern edge of the Badain Jaran Desert, and, more specifically, investigated the effects of Calligonum mongolicum, a dominant shrub species, on both abiotic environmental variables and the performance of sub-canopy plant species. We found that shrubs can improve sub-canopy water regimes, soil properties, plant biomass, density, cover, and richness and, more importantly, that the positive effect of shrubs on sub-canopy soil moisture during the summer diminishes as rainfall decreases, a pattern that partly explains the collapse of the positive interaction between shrubs and their understory plants. These results provide empirical evidence that the positive effect of shrubs on understory plant communities in extreme arid environments may decline and become neutral with increasing drought stress.
Data from: Plant interactions as biotic drivers of plasticity in leaf litter traits and decomposability of Quercus petraea
The importance of plant litter traits and decomposability for nutrient cycling processes and plant community dynamics through plant-litter-soil feedbacks has been largely emphasized. However, the role of biotic interactions as drivers of intraspecific variability in litter traits remains surprisingly little studied. In this study, we used a large-scale, multi-site network of long-term tree removal experiments manipulating the abundance of a foundation tree species, i.e. Quercus petraea, to assess how plant interactions control intraspecific variation in oak leaf litter traits and decomposability. We studied 19 plots across eight experimental sites covering a large gradient of oak abundance, stand age and local abiotic context. Oak leaf litter quality strongly declined with tree removal in early forest successional stage. Litter became poorer in nutrients such as N and Mg and richer in secondary metabolites such as lignin and condensed tannins. This in turn slowed its decomposition. Importantly, litter N loss switched from N release to N immobilization. Variance partitioning indicated that oak abundance explained as much variation in oak leaf litter traits as oak age and twice as much as soil inherent fertility. Confirmatory path analysis revealed that the decline of oak leaf litter quality induced by tree removal was most likely driven by a shift in understory plant species composition. Plasticity of oak leaf litter traits to the shortage of nutrient supply related to the development of understory plants competitors with higher nutrient capture and retention ability could potentially explain this response pattern. Our data also give consistent but weaker support that the decline of oak leaf litter quality could be driven by alleviated competition for light among canopy trees and subsequent enhanced crown exposure to light. Overall, our study provides evidence that biotic factors such as plant interactions are major drivers of plasticity in leaf litter traits and decomposability. This finding contributes to the emerging view that phenotypic plasticity is fundamentally related to biotic interactions for sessile organisms, especially for long-lived and large plant species such as trees. Taking this source of functional diversity into account could help us to better understand plant community dynamics and ecological processes in terrestrial ecosystems.
Data from: Spatial and temporal aridity gradients provide poor proxies for plant-plant interactions under climate change: a large-scale experiment
1. Plant-plant interactions may critically modify the impact of climate change on plant communities. However, the magnitude and even direction of potential future interactions remains highly debated, especially for water limited ecosystems. Predictions range from increasing facilitation to increasing competition with future aridification. 2. The different methodologies used for assessing plant-plant interactions under changing environmental conditions may affect the outcome but they are not equally represented in the literature. Mechanistic experimental manipulations are rare compared to correlative approaches that infer future patterns from current observations along spatial climatic gradients. 3. Here, we utilize a unique climatic gradient in combination with a large-scale, long-term experiment to test whether predictions about plant-plant interactions yield similar results when using experimental manipulations, spatial gradients or temporal variation. We assessed shrub-annual interactions in three different sites along a natural rainfall gradient (spatial) during 9 years of varying rainfall (temporal) and 8 years of dry and wet manipulations of ambient rainfall (experimental) that closely mimicked regional climate scenarios. 4. The results were fundamentally different among all three approaches. Experimental water manipulations hardly altered shrub effects on annual plant communities for the assessed fitness parameters biomass and survival. Along the spatial gradient, shrub effects shifted from clearly negative to mildly facilitative towards drier sites, whereas temporal variation showed the opposite trend: more negative shrub effects in drier years. 5. Based on our experimental approach, we conclude that shrub-annual interaction will remain similar under climate change. In contrast, the commonly applied space-for time approach based on spatial gradients would have suggested increasing facilitative effects with climate change. We discuss potential mechanisms governing the differences among the three approaches. 6. Our study highlights the critical importance of long-term experimental manipulations for evaluating climate change impacts. Correlative approaches, e.g. along spatial or temporal gradients, may be misleading and overestimate the response of plant-plant interactions to climate change.
Data from: Experimental evidence for fundamental, and not realised, niche partitioning in a plant-herbivore community interaction network
Patterns of niche partitioning can result from local ecological interactions (e.g. interspecific competition) occurring within a contemporary time frame (realised niche partitioning). Alternatively they may represent the end-product of historical processes acting over long time frames (fundamental niche partitioning). Niche partitioning is often detected by analysing patterns of resource use within communities, but experiments are rarely conducted to test whether patterns of non-overlapping resource use reflect realised or fundamental niche partitioning. We studied a community of restio leafhoppers from the genus Cephalelus, and their host plants, the Restionaceae (restios). We used network and experimental approaches to determine whether network modularity (a measure of niche partitioning within local communities) reflects fundamental or realised niche partitioning. Using a weighted modularity index for two party networks (e.g. insect - plant) we determined whether the network of this community is modular (i.e. consists of groups of species interacting strongly, with weak interactions between groups). We also aimed to identify specific Cephalelus - restio modules (groups). Using knowledge of module membership to design experiments, we tested whether Cephalelus species from two different modules, C. uncinatus and C. pickeri, prefer and perform better on restios from their own modules versus restios from other modules. These experiments were performed under controlled conditions, eliminating the influences of competition and predation on host choices. The Cephalelus – restio community was modular, implying niche partitioning. Cephalelus also preferred and performed better on restios from their own modules in the absence of local contemporary factors. Most niche partitioning in the investigated Cephalelus community, is not caused by local interactions, and thus host use patterns represent fundamental niches. Our findings highlight the importance of understanding local community structure in the light of processes extrinsic to the local community context.
Data from: Mechanisms of plant–plant interactions: concealment from herbivores is more important than abiotic-stress mediation in an African savannah
Recent work on facilitative plant–plant interactions has emphasized the importance of neighbours' amelioration of abiotic stress, but the facilitative effects of neighbours in reducing plant apparency to herbivores have received less attention. Whereas theory on stress reduction predicts that competition should be more important in less stressful conditions, with facilitation becoming more important in harsh environments, apparency theory suggests that facilitation should be greater in the presence of herbivores, where it is disadvantageous to be conspicuous regardless of abiotic stress level. We tested the relative strength of neighbours' stress reduction versus apparency reduction on survival, growth, reproduction and lifetime fitness of Hibiscus meyeri, a common forb in central Kenya, using neighbour removals conducted inside and outside large-herbivore exclosures replicated in arid and mesic sites. In the absence of herbivores, neighbours competed with H. meyeri in mesic areas and facilitated H. meyeri in arid areas, as predicted by stress-reduction mechanisms. By contrast, neighbours facilitated H. meyeri in the presence of herbivory, regardless of aridity level, consistent with plant apparency. Our results show that the facilitative effects arising from plant apparency are stronger than the effects arising from abiotic stress reduction in this system, suggesting that plant-apparency effects may be particularly important in systems with extant large-herbivore communities.
Data from: Ontogenetic responses of four plant species to additive and interactive effects of land-use history, canopy structure and herbivory
The strength of interactions among species is often highly variable in space and time, and a major challenge in understanding context-dependent effects of herbivores lies in disentangling habitat-mediated from herbivore-mediated effects on plant performance. We conducted a landscape-scale experiment that manipulated light availability in woodlands with either a history of agricultural use or no history of agricultural use and coupled this with performance measurements of three life stages on four perennial herbaceous species exposed to varying levels of herbivory. We found that the context-dependent effects of herbivory on plant performance changed as plants grew: juvenile plant survival was reduced by herbivores in low-light habitats whereas biomass of adult plants was reduced by a more diverse insect fauna in high-light environments. A history of agricultural land use also had negative effects on seedling establishment and adult performance, independent of herbivory. Synthesis. This work experimentally separates the habitat-mediated effects on plant performance from the herbivore-mediated effects on plant performance and highlights how context-dependent interactions depend on plant ontogenetic stages.
Data from: Do artificial nectar feeders affect bat–plant interactions in an Ecuadorian cloud forest?
Plant–pollinator interactions are critical to ecosystems. However, when artificial nectar feeders are available in an area, they could draw pollinators away from plants. We tested the effects of artificial nectar feeders in an Ecuadorian cloud forest on four aspects of bat–plant interactions: (1) bat relative abundance; (2) bat pollen loads; (3) flower visitation rates, and (4) breeding success of a bat-pollinated species (Burmeistera glabrata). We divided the study site into areas close to (~30 m) and far from (~500 m) three different feeder sites. At each distance, we captured nectar bats (Anoura caudifer, Anoura cultrata, and Lonchophylla robusta) to estimate their relative abundance and to collect pollen from fur and fecal samples. We also videotaped flowers to estimate bat visitation rates and recorded different breeding success variables of B. glabrata. We found that areas close to feeders have higher relative bat abundance by a factor of 40. In spite of this, the presence of feeders did not affect bat pollen loads, nor the flower visitation rates and breeding success of B. glabrata. Interestingly, there were differences in pollen loads between the three bat species, in that L. robusta individuals rarely carried pollen and were only captured near feeders.
Data from: The effects of rainforest fragment area on the strength of plant-pathogen interactions
Pathogenic interactions between fungi and plants facilitate plant species coexistence and tropical rainforest diversity. Such interactions, however, may be affected by forest fragmentation as fungi are susceptible to anthropogenic disturbance. To examine how fragmentation affects fungus-induced seed and seedling mortality, we sowed seeds of six plant species in soils collected from 21 forest fragments. We compared seedling establishment in unmanipulated soils to soils treated with fungicides. Fungicides increased germination of Toona ciliata seeds and decreased mortality of Syzygium rubicundum and Olea dioica seedlings. The fungus-induced mortality of one of these species, S. rubicundum, decreased with decreasing fragment size, indicating that its interactions with pathogenic fungi may weaken as fragments become smaller. We provide evidence that a potential diversity-maintaining plant-fungus interaction weakens in small forest fragments and suggest that such disruptions may have important long-term consequences for plant diversity. We, however, emphasize the need for further research across rainforest plant communities to better understand the future of diversity in fragmented rainforest landscapes.
Bacterial community richness shifts the balance between volatile organic compound-mediated microbe-pathogen and microbe-plant interactions
Even though bacteria are important in determining plant growth and health via volatile organic compounds (VOCs), it is unclear how these beneficial effects emerge in multi-species microbiomes. Here we studied this using a model plant-bacteria system, where we manipulated bacterial community richness and composition and determined the subsequent effects on VOC production and VOC-mediated pathogen suppression and plant growth-promotion. We assembled VOC-producing bacterial communities in different richness levels ranging from one to twelve strains using three soil-dwelling bacterial genera (Bacillus, Paenibacillus and Pseudomonas) and investigated how the composition and richness of bacterial community affect the production and functioning of VOCs. We found that VOC production correlated positively with pathogen suppression and plant growth-promotion and that all bacteria produced a diverse set of VOCs. However, while pathogen suppression was maximized at intermediate community richness levels when the relative amount and the number of VOCs were the highest, plant growth-promotion was maximized at low richness levels and was only affected by the relative amount of plant growth-promoting VOCs. The contrasting effects of richness could be explained by differences in the amount and number of produced VOCs and by opposing effects of community productivity and evenness on pathogen suppression and plant-growth promotion along the richness gradient. Together, these results suggest that the number of interacting bacterial species and the structure of the rhizosphere microbiome drive the balance between VOC-mediated microbe-pathogen and microbe-plant interactions potentially affecting plant disease outcomes in natural and agricultural ecosystems.
Data from: Diffuse symbioses: roles of plant–plant, plant–microbe and microbe–microbe interactions in structuring the soil microbiome
A conceptual model emphasizing direct host–microbe interactions has dominated work on host-associated microbiomes. To understand plant–microbiome associations, however, broader influences on microbiome composition and functioning must be incorporated, such as those arising from plant–plant and microbe–microbe interactions. We sampled soil microbiomes associated with target plant species (Andropogon gerardii, Schizachyrium scoparium, Lespedeza capitata, Lupinus perennis) grown in communities varying in plant richness (1-, 4-, 8- or 16-species). We assessed Streptomyces antagonistic activity and analysed bacterial and Streptomyces populations via 454 pyrosequencing. Host plant species and plant richness treatments altered networks of coassociation among bacterial taxa, suggesting the potential for host plant effects on the soil microbiome to include changes in microbial interaction dynamics and, consequently, co-evolution. Taxa that were coassociated in the rhizosphere of a given host plant species often showed consistent correlations between operational taxonomic unit (OTU) relative abundance and Streptomyces antagonistic activity, in the rhizosphere of that host. However, in the rhizosphere of a different host plant species, the same OTUs showed no consistency, or a different pattern of responsiveness to such biotic habitat characteristics. The diversity and richness of bacterial and Streptomyces communities exhibited distinct relationships with biotic and abiotic soil characteristics. The rhizosphere soil microbiome is influenced by a complex and nested array of factors at varying spatial scales, including plant community, plant host, soil edaphics and microbial taxon and community characteristics.
Data from: Land use in mountain grasslands alters drought response and recovery of carbon allocation and plant-microbial interactions
1. Mountain grasslands have recently been exposed to substantial changes in land-use and climate and in the near future will likely face an increased frequency of extreme droughts. To date is not known how the drought responses of carbon (C) allocation, a key process in the C cycle, are affected by land-use changes in mountain grassland. 2. We performed an experimental summer drought on an abandoned grassland and a traditionally managed hay meadow and traced the fate of recent assimilates through the plant-soil continuum. We applied two 13CO2 pulses, at peak drought and in the recovery phase shortly after rewetting. 3. Drought decreased total C uptake in both grassland types and led to a loss of aboveground carbohydrate storage pools. The belowground C allocation to root sucrose was enhanced by drought, especially in the meadow, which also held larger root carbohydrate storage pools. 4. The microbial community of the abandoned grassland comprised more saprotrophic fungal and Gram (+) bacterial markers compared to the meadow. Drought increased the newly introduced AM and saprotrophic fungi:bacteria ratio in both grassland types. At peak drought the 13C transfer into AM fungi, saprotrophic fungi and Gram (-) bacteria was more strongly reduced in the meadow than in the abandoned grassland, which contrasted the patterns of the root carbohydrate pools. 5. In both grassland types the C allocation largely recovered after rewetting. Slowest recovery was found for AM fungi and their 13C uptake. In contrast, all bacterial markers quickly recovered C uptake. In the meadow, where plant nitrate uptake was enhanced after drought, C uptake was even higher than in control plots. 6. Synthesis. Our results suggest that resistance and resilience (i.e. recovery) of plant C dynamics and plant-microbial interactions are negatively related, i.e. high resistance is followed by slow recovery and vice versa. The abandoned grassland was more resistant to drought than the meadow and possibly had a stronger link to AM fungi that could have provided better access to water through the hyphal network. In contrast, meadow communities strongly reduced C allocation to storage and C transfer to the microbial community in the drought phase, but in the recovery phase invested C resources in the bacterial communities to gain more nutrients for regrowth. We conclude that management of mountain grasslands increases their resilience to drought.
Data from: Land-use legacies and present fire regimes interact to mediate herbivory by altering the neighboring plant community
Past and present human activities, such as historic agriculture and fire suppression, are widespread and can create depauperate plant communities. Although many studies show that herbivory on focal plants depends on the density of herbivores or the composition of the surrounding plant community, it is unclear whether anthropogenic changes to plant communities alter herbivory. We tested the hypothesis that human activities that alter the plant community lead to subsequent changes in herbivory. At 20 sites distributed across 80 300 hectares, we conducted a field experiment that manipulated insect herbivore access (full exclosures and pseudo-exclosures) to four focal plant species in longleaf pine woodlands with different land-use histories (post-agricultural sites or non-agricultural sites) and degrees of fire frequency (frequent and infrequent). Plant cover, particularly herbaceous cover, was lower in post-agricultural and fire suppressed woodlands. Density of the dominant insect herbivore at our site (grasshoppers) was positively related to plant cover. Herbivore access reduced biomass of the palatable forb Solidago odora in frequently burned post-agricultural sites and in infrequently burned non-agricultural woodlands and increased mortality of another forb (Pityopsis graminifolia), but did not affect two other less palatable species (Schizachyrium scoparium and Tephrosia virginiana). Herbivory on S. odora exhibited a hump-shaped response to plant cover, with low herbivory at low and high levels of plant cover. Herbivore density had a weak negative effect on herbivory. These findings suggest that changes in plant cover related to past and present human activities can modify damage rates on focal S. odora plants by altering grasshopper foraging behavior rather than by altering local grasshopper density. The resulting changes in herbivory may have the potential to limit natural recovery or restoration efforts by reducing the establishment or performance of palatable plant species.
Data from: Host plant associations and geography interact to shape diversification in a specialist insect herbivore
Disentangling the processes underlying geographic and environmental patterns of biodiversity challenges biologists as such patterns emerge from eco-evolutionary processes confounded by spatial autocorrelation among sample units. The herbivorous insect, Belonocnema treatae (Hymenoptera: Cynipidae), exhibits regional specialization on three plant species whose geographic distributions range from sympatry through allopatry across the southern USA. Using range-wide sampling spanning the geographic ranges of the three host plants and genotyping-by-sequencing of 1,217 individuals, we tested whether this insect herbivore exhibited host-plant-associated genomic differentiation while controlling for spatial autocorrelation among the 58 sample sites. Population genomic structure based on 40,699 SNPs was evaluated using the hierarchical Bayesian model ENTROPY to assign individuals to genetic clusters and estimate admixture proportions. To control for spatial autocorrelation, distance-based Moran's eigenvector mapping was used to construct regression variables summarizing spatial structure inherent among sample sites. Distance based redundancy analysis (dbRDA) incorporating the spatial variables was then applied to partition host-plant-associated differentiation (HAD) from spatial autocorrelation. By combining ENTROPY and dbRDA to analyze SNP data we unveiled a complex mosaic of highly structured differentiation within and among gall former populations finding evidence that geography, HAD and spatial autocorrelation all play significant roles in explaining patterns of genomic differentiation in B. treatae. While dbRDA confirmed host association as a significant predictor of patterns of genomic variation, spatial autocorrelation among sites explained the largest proportion of variation. Our results demonstrate the value of combining dbRDA with hierarchical structural analyses to partition spatial/environmental patterns of genomic variation.
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Allen Brain Atlas
Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.
Annotated Behaviour and Observability Dataset (ABODe)
ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.
DANDI Archive for NWB datasets
DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.
International Brain Laboratory public data
The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.