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opencc-zeroDec 2018View details →

Data from: Beyond preference and performance: host plant selection by monarch butterflies, Danaus plexippus

The connection between adult preferences and offspring performance is long-standing issue in understanding the evolutionary and ecological forces that dictate host associations and specialization in herbivorous insects. Indeed, decisions made by females about where to lay their eggs have direct consequences for fitness and are influenced by interacting factors including offspring performance, defence, and competition. Nonetheless, in addition to these attributes of the offspring, a female's choices may be affected by her own prior experience. Here we examined oviposition preference, larval performance, and the role of learning in the monarch butterfly, Danaus plexippus, which encounters diverse milkweed host species across its broad range and over the course of migration. Monarch females consistently preferred to oviposit on Asclepias incarnata subspecies pulchra. This plant, however, was associated with poor caterpillar growth, low sequestration of toxins, and the highest plant defences (latex and trichomes). We examined flexibility in this apparently maladaptive preference by testing the impact of previous experience and competition on preference. Experience laying on an alternative plant species enhanced preference for that species in contrast to A. i. pulchra. In addition, presence of a (competing) conspecific caterpillar on A. i. pulchra had a strongly deterrent effect and reversed host plant preferences. Thus, monarch butterflies exhibit preferences contrary to what would be expected based on offspring development and sequestered defences, but their preferences are altered by learning and competition, which may allow butterflies to shift preferences as they encounter diverse milkweeds across the landscape. Learning and perception of threats (i.e., competition or predation) may be critical for most herbivorous insects, which universally experience heterogeneity among their potential host plants.

opencc-zeroDec 2015View details →

Data from: Genotypic diversity mitigates negative effects of density on plant performance: a field experiment and life-cycle analysis of common evening primrose Oenothera biennis

1.Genotypic diversity in plant populations is known to enhance plant performance and ecosystem function. Nonetheless, the effect of genotypic diversity has rarely been examined across a population's lifecycle despite the expectation that changing conditions, such as population density, will alter the benefits of diversity. 2.We simultaneously manipulated a component of genotypic diversity (richness, the number of genotypes) and density of common evening primrose Oenothera biennis to address the consequences for herbivory and lifetime fitness in a two-year field experiment that spanned seed germination to life-time fruit production. We genotyped >1100 seedlings with microsatellite DNA markers to determine realized diversity and density in plots sown with O.biennis seeds. Our design achieved quantitative variation in plant density and diversity, with one to 44 individuals established in field plots and two to eight genotypes per polyculture plot (based on microsatellite analysis of reproductive plants). 3.We found a strong interaction between seed density and genetic diversity, with germination and establishment being 24% higher in genetic polycultures than monocultures, but only at low seed density. At high seed density, the opposite pattern emerged, with polycultures having 12% fewer individuals established than monocultures. Initial effects of emergence on plot density persisted through to the fruiting stage. 4.Higher plant densities result in increased mortality, decreased probability of reproduction, decreased plant height, and lower levels of life-time fruit production per plant. Increasing genotypic diversity increased the probability of reproduction overall, and showed a significant interaction with plant density mitigating the negative effects of high density on individual height and lifetime fruit production. 5.Synthesis. Plant density and genotypic diversity interacted from the very earliest stages of seed germination and establishment of O. biennis. This effect persisted over the two-year life-cycle of plants, and genotypic diversity buffered against the negative fitness consequences of high plant density. These results imply a dynamic interplay between the long-held paradigm of density effects in plant ecology and the genetic structure of populations.

opencc-zeroDec 2013View details →

Data from: Loss of heterosis and family-dependent inbreeding depression in plant performance and resistance against multiple herbivores under drought stress

1. Inbreeding depression (ID), outbreeding depression (OD) and heterosis can occur concurrently in plant populations. ID often increases under environmental stress, but the combined effects of inbreeding, outbreeding between populations and environmental stress, such as drought, on plant performance and herbivore resistance remain unclear. 2. In order to determine environment-dependent and family-dependent ID, OD and heterosis we conducted a common garden experiment with plants from five populations of Brassica nigra. Inbred, within-population outbred and between-population outbred plant families were exposed to drought or ambient water levels. We recorded the abundance and damage caused by specialist herbivores from contrasting feeding guilds, i.e. the phloem-feeding Brevicoryne brassicae, the leaf-chewing Psylliodes chrysocephalus and the stem-boring Ceutorhynchus quadridens larvae. 3. Drought stress had negative effects on growth, herbivore resistance and resistance against B. brassicae and positive effects on investments in reproductive output and plant secondary metabolites (sinigrin). We found drought stress-induced loss of heterosis for plant height and investment in reproductive output. Between-population outbred plants were more sensitive to drought stress in terms of above-ground biomass compared to within-population outbred plants. 4. Drought and inbreeding synergistically negatively influenced traits related to growth and reproductive output (environment-dependent inbreeding depression, EDID). There was high variation among families within populations in the degree of ID and EDID. Genetic variation in EDID could buffer the negative effects of genetic stress associated with habitat fragmentation and concurrent environmental stress. In order to capture fully the effects of both inbreeding and between-population outbreeding under stress the different spatial scales of the effects of inbreeding and between-population outbreeding should be taken into account. 5. Synthesis. Our results indicate that drought stress influences not only inbreeding depression (ID), but also heterosis. These findings shed new light on the combined effects of anthropogenic environmental change and the genetic consequences of habitat fragmentation on plants and their interactions with other organisms. Conservation programmes aiming to restore genetically degraded populations with the translocation of individuals between populations should consider environmental stress as a risk factor.

opencc-zeroDec 2017View details →

Data from: Additive effects of plant chemotype, mutualistic ants and predators on aphid performance and survival

1. Cascading effects in ecological systems acting across three or more trophic levels can be either of a resource-based (bottom-up) or natural enemy-based (top-down) nature. But, due to their complexity these effects are often considered separately and their relative strength, acting simultaneously, remains unknown. 2. In a semi-natural field experiment using tansy (Tanacetum vulgare L.) and the specialised tansy aphid Metopeurum fuscoviride Stroyan as a model system, we compared the effects of four distinct plant chemotypes (i.e. bottom-up), defined by the bouquet of their volatile terpenoids, on aphid population dynamics by manipulating the presence/absence of mutualistic ants and presence/absence of naturally-occurring predators (i.e. top-down). 3. Predators reduced aphid abundance and colony survival but did not reduce initial growth rate due to a time lag until predators arrived on the plants. Ants directly benefited initial aphid growth rates and abundance, even in the absence of predators, but not the number of days an aphid colony persisted on the plant. 4. Plant chemotype directly affected aphid growth rate and final abundances across the different plants and indirectly affected the abundances of tending ants and predators through effects on aphids. We found that tending ants were more abundant on one plant chemotype. Although ant abundance did not affect aphid population development, it became clear that ants had a preference towards aphids on certain chemotypes. However, a higher number of predators led to a lower number of aphids. 5. The results confirm the importance of plant chemical variation, acting through multiple effects on many species in arthropod communities, and support results from field studies. In a natural population, with a diverse selection of host-plant variants, aphid populations and their interacting species can therefore be structured at the level of an individual plant. Specialist aphids on patchily-distributed host plants can exhibit metacommunity dynamics at very local scales. Plant within-species variation within a local population is often ignored in metacommunity ecology, yet our work shows that this can have strong effects on insect-ant-natural enemy dynamics and therefore future research should incorporate this into current theory and experimental studies.

opencc-zeroDec 2017View details →

Data from: Effect of plant root symbionts on performance of native woody species in competition with an invasive grass in multispecies microcosms

The majority of terrestrial plants form mutualistic associations with arbuscular mycorrhizal fungi (AMF) and rhizobia (i.e. nitrogen fixing bacteria). Understanding these associations has important implications for ecological theory and for restoration practice. Here we tested whether the presence of AMF and rhizobia influence the performance of native woody plants invaded by a non-native grass in experimental microcosms. We planted eight plant species (i.e. Acacia acuminata, A. microbotrya, Eucalyptus loxophleba subsp. loxophleba, E. astringens, Calothamnus quadrifidus, Callistemon phoeniceus, Hakea lissocarpha and H. prostrata) in microcosms of field-conditioned soil with and without addition of AMF and rhizobia in a fully factorial experimental design. After seedling establishment, we seeded half the microcosms with an invasive grass Bromus diandrus. We measured shoot and root biomass of native plants and Bromus, and on roots, the percentage colonization by AMF, number of rhizobia-forming nodules and number of proteaceous root clusters. We found no effect of plant root symbionts or Bromus addition on performance of myrtaceous, and as predicted, proteaceous species as they rely little or not at all on AMF and rhiozbia. Soil treatments with AMF and rhiozbia had a strong positive effect (i.e. larger biomass) on native legumes (A. microbotrya and A. acuminata). However, the beneficial effect of root symbionts on legumes became negative (i.e. lower biomass and less nodules) if Bromus was present, especially for one legume, i.e. A. acuminata, suggesting a disruptive effect of the invader on the mutualism. We also found a stimulating effect of Bromus on root nodule production in A. microbotrya and AMF colonization in A. acuminata which could be indicative of legumes' increased resource acquisition requirement, i.e. for nitrogen and phosphorus, respectively, in response to the Bromus addition. We have demonstrated the importance of measuring belowground effects because the aboveground effects gave limited indication of the effects occuring belowground.

opencc-zeroDec 2017View details →

Data from: Males, but not females, perform strategic mate searching movements between host plants in a leaf beetle with scramble competition polygyny

1. Mate searching is assumed to be performed mostly by males, but when females benefit from multiple mating or are under risk of failing to mate, they may also perform mate searching. This is especially important in scramble competition polygynies, in which mate searching is the main mechanism of mate competition. Typically, more mobile individuals are expected to achieve higher mating success because mobility increases their probability of finding mates. 2. If we assume individual movements are mainly explained by mate searching in scramble competition polygynies, we can investigate searching strategies by asking when individuals should leave their location and where they should go. We hypothesize that individuals will leave their locations when mating opportunities are scarce and will seek spatially close sites with better mating opportunities. 3. We tested these hypotheses for males and females of Leptinotarsa undecimlineata, a leaf beetle with scramble competition polygyny in which both sexes are promiscuous. Individuals mate and feed exclusively on Solanum plants, thus individual movements can be described as switches between plants. 4. Females were less likely than males to leave isolated plants, and both males and females moved preferentially to neighbouring plants. Males were more likely to leave when the local number of females was low, and the number of males was high. They moved to plants with more females, a behaviour consistent with a mate searching strategy. Females were more likely to move to plants with fewer males and many females, a behaviour consistent with male harassment avoidance. 5. Strategic movement is widely considered in foraging context, but seldom in a mate searching context. Considering that selection to minimize searching costs, maximize mating success, and minimize harassment may be ubiquitous in nature, we argue that strategic movements by mate searching individuals are likely to occur in many species.

opencc-zeroNov 2021View details →

Performance and microbiota of Lupinus polyphyllus for Plant and Soil

Purpose: In cold climates, glyphosate residues may linger in soils, with effects on plant-microbe interactions and, consequently, plant performance. Here, we explore the influence of glyphosate residues on the endophytic microbiota (bacteria and fungi) and performance of the perennial nitrogen-fixing weed Lupinus polyphyllus. Methods: In a common garden, we grew plants from six populations of L. polyphyllus in glyphosate-treated or untreated control soils, with or without additional phosphorus. We sampled plant microbiota (leaves, roots, nodules) and assessed plant performance based on six traits: height, retrogression probability (i.e. shrinkage), biomass, root:shoot ratio, nodule number, and nodule viability. Results: The richness of plant endophytic microbial communities was determined by soil phosphorus level rather than by glyphosate treatment. However, for bacteria, the composition of these communities differed between glyphosate-treated and control soils across plant tissue types; no difference was observed for fungi. The plant bacterial communities in both soil types were dominated by potential nitrogen-fixing bacteria belonging to family Bradyrhizobiaceae, and particularly so in glyphosate-treated soils. Overall, though, these changes in plant bacterial communities had a minor effect on plant performance: the only difference we detected was that the probability of retrogression was occasionally higher in glyphosate-treated soils than in control soils. Conclusion: Our findings indicate that glyphosate-based herbicides, when applied at the recommended frequency and concentration, may not have critical effects on the growth of short-lived weeds after the safety period has passed; however, the endophytic microbiota of such weeds may experience longer-lasting shifts in community structure.

opencc-zeroNov 2021View details →

Beneficial worm allies warn plants of parasite attack belowground and reduce aboveground herbivore preference and performance

We investigated responses of tomato (Solanum lycopersicum) to two functional guilds of nematodes - plant parasite (Meloidogyne javanica) and entomopathogens (Heterorhabditis bacteriophora, Steinernema feltiae belowground, and S. carpocapsae) - as well as a leaf mining insect (Tuta absoluta) aboveground. Our results indicate that entomopathogenic nematodes (EPNs): 1) induced plant defense responses, 2) reduced root knot nematode (RKN) infestation belowground and 3) reduced herbivore (T. absoluta) host preference and performance aboveground. Concurrently, we investigated the plant signaling mechanisms underlying these interactions using biochemical and transcriptome analyses. We found that both entomopathogen and parasite triggered immune responses in plant roots with shared gene expression. Tomato plants responded similarly to presence of RKN or EPN in the rootzone, by rapidly activating polyphenol oxidase (PPO) and guaiacol peroxidase (GP) activity in roots, but simultaneously suppressed this activity in aboveground tissues. We quantified changes in gene expression in tomato that may play essential roles in defense response to RKN, which were also coincidentally triggered by EPN. For example, PR-14 expression was greater in plants inoculated with EPN than in plants co-inoculated with both nematode functional guilds. Overall, EPN inoculation directly mediated enhanced plant defense and reduced subsequent RKN infection. Likewise, we show that EPNs modulate plant defense against RKN invasion, in part, by suppressing active expression of antioxidant enzymes. Inoculation of tomato roots with EPNs belowground reduced both host preference and performance of the aboveground herbivore, T. absoluta. Inoculations of roots with EPN also triggered an immune response in tomato via up-regulated phenylpropanoid metabolism and synthesis of protease inhibitors (PIs) in plant tissues, which could explain an observed decrease in egg laying and developmental performance exhibited by herbivores on EPN-inoculated plants. Our results support the hypothesis that subterranean EPNs activate a battery of plant defenses associated with systemic acquired resistance (SAR) and/or induced systemic resistance (ISR) with concomitant antagonistic effects on temporally co-occurring subterranean plant pathogenic nematodes and terrestrial herbivores.

opencc-by-4.0Jan 2022View details →

Data linked to publication entitled "Biochar derived from Acai agroindustry waste enhances nutritional status and biomass in young Eucalyptus urophylla plants: Evidence connected to root development and leaf performance"

Data linked to publication entitled "Biochar derived from Acai agroindustry waste enhances nutritional status and biomass in young Eucalyptus urophylla plants: Evidence connected to root development and leaf performance"

opencc-zeroMar 2022View details →

Direct and legacy-mediated drought effects on plant performance are species-specific and depend on soil community composition

Droughts affect plant communities, but their impacts may be mediated by soil biota. Soil communities may ameliorate drought stress, and droughts may leave legacies of altered soil communities that may affect future plant growth. However, it is not yet understood which groups of soil biota in particular affect plant performance under drought, nor which groups contribute to drought-legacy effects on future plant growth. We hypothesized that increasing soil-community complexity ameliorates drought stress and that drought-legacy effects are species-specific and soil-community-dependent. To test these hypotheses, we performed a two-phase experiment with six grassland species. In the first phase, we examined plant performance under drought and ambient conditions, in soils inoculated with a sterilized inoculum, or increasingly complex soil communities created by wet-sieving through 20-, 40-, and 200-µm mesh sieves. In the second phase, we examined drought-legacy effects on conspecific plant performance. We separately analysed plant performance in both phases, and integrated data from both phases using structural equation models. Drought effects on first-phase root biomass depended on soil inoculum, and this interaction differed among plant species, while effects on shoot biomass differed among species, but did not depend on inoculum. Only one species experienced drought-stress-ameliorating effects of soil biota. Drought-legacy effects on plant performance were positive, but depended on soil inoculum in case of root biomass, and on soil inoculum and species identity in case of shoot biomass. Drought-legacy effects were often mediated by first-phase biomass. In some species this effect was independent of inoculum, suggesting an abiotic legacy effect. In others, low first-phase biomass corresponded with high second-phase performance in presence of the most complex soil community. We conclude that drought-legacy effects on plant performance were soil-community-dependent but positive, suggesting that plants establishing after drought may benefit from increased nutrient availability and more positive impacts of soil biota.

Fig. 5 in Pretrained Convolutional Neural Networks Perform Well in a Challenging Test Case: Identification of Plant Bugs (Hemiptera: Miridae) Using a Small Number of Training Images

Fig. 5. Visualization of a feature with high importance and a feature with low importance from a configuration B. The importance of these features for the identification accuracy was determined using permutation tests (see the methods). For each taxon or group (rows) several randomly selected specimens (columns) are shown. For the two selected Global Average Pooling layer features, the corresponding features of the preceding (Max Pooling) layer are visualized as those show specific image parts that had higher activations.Yellow represents the maximal activation strength; dark blue represents the minimal activation strength.

Fig. 2 in Pretrained Convolutional Neural Networks Perform Well in a Challenging Test Case: Identification of Plant Bugs (Hemiptera: Miridae) Using a Small Number of Training Images

Fig. 2. Schematic representation of the networks used. On top are the convolutional layers of VGG16, grouped into five blocks. Output of each Max Pooling layer is fed into Global Average Pooling layer. Numbers near each block name indicate number of features in the Global Average Pooling layer. Height of layers roughly corresponds to resolution (except for Global Average Pooling layer), while width roughly corresponds to the number of feature maps or features produced.Then, in approach A, outputs of five blocks are concatenated and passed to the linear classifier. In approach B, output of only one block (block 3 in the final configuration) is passed to the linear classifier. In approach C CNN outputs are as in approach A, but instead connected to a DNN with two layers of 320 fully connected (FC) neurons followed by a prediction layer (PL), with number of neurons equal to number of species classified. Finally, approach D features CNN as in approach B which is connected to DNN as in approach C.

Fig. 1 in Pretrained Convolutional Neural Networks Perform Well in a Challenging Test Case: Identification of Plant Bugs (Hemiptera: Miridae) Using a Small Number of Training Images

Fig. 1. Dorsal habitus photos of males and females of Tuxedo spp., Pygovepres vaccinicola, and Phallospinophylus setosus generated for and used in this study.

Fig. 4 in Pretrained Convolutional Neural Networks Perform Well in a Challenging Test Case: Identification of Plant Bugs (Hemiptera: Miridae) Using a Small Number of Training Images

Fig. 4. Validation accuracy and accuracy on test data for SVM linear classifier (A, B) and DNN approaches (C, D) for the three datasets.

Fig. 3 in Pretrained Convolutional Neural Networks Perform Well in a Challenging Test Case: Identification of Plant Bugs (Hemiptera: Miridae) Using a Small Number of Training Images

Fig. 3. Identification accuracy for the male (top) and female (bottom) Tuxedo dataset for the five selected resolutions and the individual blocks 1–5 and the concatenated block.

opencc-by-4.0Feb 2017View details →

Supplementary material 4 from: Connolly BM, Powers J, Mack RN (2017) Biotic constraints on the establishment and performance of native, naturalized, and invasive plants in Pacific Northwest (USA) steppe and forest. NeoBiota 34: 21-40. https://doi.org/10.3897/neobiota.34.10820

Table S4–S7 : Explanation note: MANOVA GLM results for seedling establishment and performance measures.

opencc-by-4.0Feb 2017View details →

Supplementary material 3 from: Connolly BM, Powers J, Mack RN (2017) Biotic constraints on the establishment and performance of native, naturalized, and invasive plants in Pacific Northwest (USA) steppe and forest. NeoBiota 34: 21-40. https://doi.org/10.3897/neobiota.34.10820

Table S2–S3, Figures S2–S3 : Explanation note: Generalized mixed model output and summary graphs using species, rather than plant immigration class, as a fixed factor in models assessing plant establishment counts and individual plant growth.

opencc-by-4.0Feb 2017View details →

Supplementary material 2 from: Connolly BM, Powers J, Mack RN (2017) Biotic constraints on the establishment and performance of native, naturalized, and invasive plants in Pacific Northwest (USA) steppe and forest. NeoBiota 34: 21-40. https://doi.org/10.3897/neobiota.34.10820

Methods S1 and Figure S1 : Explanation note: Protocol and results figure summarizing light transmittance in disturbed vs. undisturbed plots in PNW steppe and forest.

opencc-by-4.0Aug 2023View details →

Dataset and R-script for Article: Increased heat tolerance of geothermal plants at the cost of reduced performance under cooler conditions

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