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opencc-zeroFeb 2024View details →

Data and R code used in: Plant geographic distribution influences chemical defenses in native and introduced Plantago lanceolata populations

Plants growing outside their native range may be confronted by new regimes of herbivory, but how this affects plant chemical defense profiles has rarely been studied. Using Plantago lanceolata as a model species, we investigated whether introduced populations show significant differences from native populations in several growth and chemical defense traits. Plantago lanceolata (ribwort plantain) is an herbaceous plant species native to Europe and Western Asia that has been introduced to numerous countries worldwide. We sampled seeds from nine native and ten introduced populations that covered a broad geographic and environmental range and performed a common garden experiment in a greenhouse, in which we infested half of the plants in each population with caterpillars of the generalist herbivore Spodoptera littoralis. We then measured size-related and resource-allocation traits as well as the levels of constitutive and induced chemical defense compounds in roots and shoots of P. lanceolata. When we considered the environmental characteristics of the site of origin, our results revealed that populations from introduced ranges were characterized by an increase of chemical defense compounds without compromising plant biomass. The concentrations of iridoid glycosides and verbascoside, the major anti-herbivore defense compounds of P. lanceolata, were higher in introduced populations than in native populations. In addition, introduced populations exhibited greater rates of herbivore-induced volatile organic compound emission and diversity, and similar chemical diversity based on untargeted analyses of leaf methanol extracts. In general, the geographic origin of the populations had a significant influence on morphological and chemical plant traits, suggesting that P. lanceolata populations are not only adapted to different environments in their native range but also in their introduced range.

opencc-zeroDec 2023View details →

Data from: Evidence for reductions in physical and chemical plant defense traits in island flora

Reduced defense against large herbivores has been suggested to be part of the "island syndrome" in plants. However, empirical evidence for this pattern is mixed. In this paper, we present two studies that compare putative physical and chemical defense traits from plants on the California Channel Islands and nearby mainland based on sampling of both field and common garden plants. In the first study, we focus on five pairs of woody shrubs from three island and three mainland locations and find evidence for increased leaf area, decreased marginal leaf spines, and decreased concentrations of cyanogenic glycosides in island plants. We observed similar increases in leaf area and decreases in defense traits when comparing island and mainland genotypes grown together in botanic gardens, suggesting that trait differences are not solely driven by abiotic differences between island and mainland sites. In the second study, we conducted a common garden experiment with a perennial herb—Stachys bullata (Lamiaceae)—collected from two island and four mainland locations. Compared to their mainland relatives, island genotypes show highly reduced glandular trichomes and a nearly 100-fold reduction in mono- and sesquiterpene compounds from leaf surfaces. Island genotypes also had significantly higher specific leaf area, somewhat lower rates of gas exchange, and greater aboveground biomass than mainland genotypes across two years of study, potentially reflecting a broader shift in growth habit. Together, our results provide evidence for reduced expression of putative defense traits in island plants, though these results may reflect adaptation to both biotic (i.e., the historical absence of large herbivores) and climatic conditions on islands.

publicApr 2024View details →

Data from: Evidence for reductions in physical and chemical plant defense traits in island flora

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publicFeb 2024View details →

Data and R code used in: Plant geographic distribution influences chemical defenses in native and introduced Plantago lanceolata populations

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edi40/100

Induction of aspen chemical defense by leaf mining, tested experimentally in 2006

This dataset summarizes the result of a manipulative experiment designed to test whether natural levels of damage by the aspen leaf miner, Phllocnistis populiella, causes the induction of foliar phenolic glycosides in small aspen ramets in the field.

openOpenJan 2013View details →

edi40/100

Induction of aspen chemical defense by leaf mining, tested experimentally in 2007.

This dataset summarizes the result of a manipulative experiment designed to test the time course of phenolic glycoside induction by small aspen (Populus tremuloides) in response to leaf mining by the aspen leaf miner, Phyllocnistis populiella.

openOpenJan 2013View details →

opencc-zeroJul 2020View details →

Data from: Chemical defenses shift with the seasonal vertical migration of a Panamanian poison frog

Dendrobatid poison frogs sequester lipophilic alkaloids from their arthropod prey to use as a form of chemical defense. Some dendrobatid frogs seasonally migrate between the leaf litter of the forest floor in the dry season to the canopy in the wet season, which may yield differences in prey (arthropods) and therefore alkaloid availability over space and time. Here, we document a seasonal vertical migration of Andinobates fulguritus (the yellow-bellied poison frog) from ground to canopy between dry and wet seasons. We observed turnover in alkaloid composition between seasons and found that dry season frogs contained a lower relative quantity of alkaloids; however, there was no change in alkaloid richness between seasons. The 77 alkaloids of 13 structural classes identified in this population appear to be derived mostly from mites and ants, though the two most common alkaloids were mite derived. Our observed shifts in defensive profiles are consistent with well-documented turnover in mite and ant communities between seasons and vertical strata. As climate change is expected to lengthen and strengthen dry seasons in many tropical regions, our results suggest that arboreal poison frogs forced to the ground for longer periods of time may see a shift in the abundance of alkaloids, possibly decreasing their defensive potential. This study provides further predictions for the wide-reaching effects of climate change, even as nuanced as charismatic poison frogs losing their poisons.

opencc-zeroAug 2019View details →

Data from: Chemical defense over decadal scales: ontogenetic allocation trajectories and consequences for fitness in a foundation tree species

1. Expression of herbivore defense traits can change dramatically during the course of plant development. Little is known, however, about the degree of genetic or sexual variation in these ontogenetic defense trajectories or whether the trajectories themselves are adaptive, especially in long‐lived species. 2. We used a 13‐year dataset of chemical defense traits, growth, and survivorship from a common garden of trembling aspen (Populus tremuloides) genotypes to document long‐term defense trajectories and their relationship to tree fitness during juvenile and early mature stages. 3. Overall, concentrations of the two principal classes of aspen defense compounds (salicinoid phenolic glycosides [SPGs] and condensed tannins [CTs]) decreased to differing degrees in foliage of juvenile trees and then remained relatively constant in maturity. Initial values, juvenile rates of change, and average mature values all exhibited significant genetic variation for both SPGs and CTs. 4. Relationships between defense trajectory parameters and metrics of tree fitness (growth and survivorship) depended on compound type and tree sex. Females with higher‐allocation SPG trajectories (high initial juvenile concentrations, slow juvenile declines, high mature concentrations) grew more slowly relative to females with lower‐allocation trajectories. In males, higher‐allocation SPG trajectories had a lesser effect on growth but were associated with reduced mortality. Juvenile CT trajectories were not correlated with tree fitness, but average CT concentration in maturity was positively related to growth in females. 5. These results suggest that ontogenetic defense trajectories are adaptive and subject to natural selection. Genotypic variation and ontogeny shape tree defensive chemistry, both independently and interactively. These patterns of defense expression have the potential to structure trophic interactions and the genetic composition of forests in both space and time.

opencc-zeroFeb 2020View details →

A non-vector herbivore indirectly increases the transmission of a vector-borne virus by reducing plant chemical defenses

<ol> <li>Vectors and viruses exist in communities consisting of many interacting species. Although the cascading effects of predators or parasitoids on disease spread via direct effects on vectors have been investigated, little is known about the effects of other free-living species in communities on the transmission of vector-borne viruses via indirect (host-plant mediated) effects on vectors.</li> <li>In the present study, we used a food web consisting of tomato plants (Solanum lycopersicum), two tomato herbivores (the vector whitefly, Bemisia tabaci, and the non-vector two-spotted spider mite, Tetranychus urticae), and a whitefly-vectored plant virus (Tomato yellow leaf curl virus, TYLCV) to study how T. urticae may affect TYLCV transmission by B. tabaci via host-plant mediated effects on B. tabaci.</li> <li>We found that T. urticae infestation promoted B. tabaci feeding and thereby increased TYLCV transmission to tomato plants. These increases were associated with T. urticae-induced reductions in two flavonoids (rutin and quercetin trisaccharide) of tomato plants. Elevation of rutin and quercetin trisaccharide levels in T. urticae-infested plants via exogenous stem applications reduced B. tabaci feeding and TYLCV transmission. Therefore, suppression of these flavonoids by T. urticae infestation was the most likely explanation for the observed changes in B. tabaci feeding behavior and TYLCV transmission.</li> <li> Our results show that by reducing flavonoids in tomato plants, a non-vector herbivore can indirectly increase the transmission of a vector-borne plant virus. These findings indicate that species that are far removed from the direct vector–virus interactions can indirectly affect vector–borne virus transmission by altering the chemical defenses of the shared host plant. </li> </ol>

opencc-zeroApr 2022View details →

Chemical defense strategies, induction timing, growth, and tradeoffs in Pinus aristata and Pinus flexilis

Tradeoffs among plant defense investment and fitness traits, including growth, are often invoked to explain evolutionary strategies targeted at resisting herbivores. Many Pinus species have specialized herbivores, including the mountain pine beetle, Dendroctonus ponderosae, (MPB), and have historically been a focus of defense investigations. We compared defense traits of two high-elevation Pinus species, P. aristata and P. flexilis, that are hosts to MPB and hypothesized to have different growth and defense traits and potential tradeoffs. Interspecific differences were assessed by sampling trees within the same stands, and intraspecific differences were assessed by sampling stands at sites across latitudes where both species co-occurred. Constitutive defenses were measured at day 0, and the timing, concentration, and composition of an induced resin defense response was assessed by sampling at 1, 4, and 30 days following either mechanical wounding only or a simulated MPB attack using its primary fungal symbiont Grosmannia clavigera. At day 4, induced resin concentrations did not differ between mechanical wounding and simulated MPB attack in either species. By day 30, resin defense concentrations in response to simulated MPB attack were greater than response to mechanical wounding and were >19-fold greater than constitutive levels. Results suggest that initial induced resin defense responses in the two species are likely generalized, with a delayed response that is targeted specifically at MPB and G. clavigera. At all sites, P. aristata had higher concentrations of constitutive and day 30 induced resin defenses compared to P. flexilis, although P. flexilis induced proportionately more. Tradeoffs in growth and defense between the species were only found at the two most climatically favorable sites where P. aristata grew slower than P. flexilis. No tradeoffs were found between the two defense types at either biological scale. Overall, our findings highlight that the two pine species growing in the same stands 1) have a delayed response to a specialized native herbivore and fungal symbiont, 2) only exhibited interspecific defense-growth tradeoffs at two climatically favorable sites, and showed no intraspecific defense-growth tradeoffs, 3) showed no tradeoffs between constitutive and induced defenses at either biological scale, and 4) have evolved different defense strategies.

opencc-zeroMay 2022View details →

Data condition dependence in biosynthesized chemical defenses of an aposematic and mimetic Heliconius butterfly

Aposematic animals advertise their toxicity or unpalatability with bright warning coloration. However, acquiring and maintaining chemical defenses can be energetically costly, and consequent associations with other important traits could shape chemical defense evolution. Here, we have tested whether chemical defenses are involved in energetic trade-offs with other traits, or whether the levels of chemical defenses are condition dependent, by studying associations between biosynthesized cyanogenic toxicity and a suite of key life-history and fitness traits in a Heliconius butterfly under a controlled laboratory setting. Heliconius butterflies are well known for the diversity of their warning color patterns and widespread mimicry, and can both sequester the cyanogenic glucosides of their Passiflora host plants and biosynthesize these toxins de novo. We find energetically costly life-history traits to be either unassociated or to show a general positive association with biosynthesized cyanogenic toxicity. More toxic individuals developed faster, had higher mass as adults, and a tendency for increased lifespan and fecundity. These results thus indicate that toxicity level of adult butterflies may be dependent on individual condition, influenced by genetic background or earlier conditions, with maternal effects as one strong candidate mechanism. Additionally, toxicity was higher in older individuals, consistent with previous studies indicating accumulation of toxins with age. As toxicity level at death was independent of lifespan, cyanogenic glucoside compounds may have been recycled to release resources relevant for longevity in these long-living butterflies. Understanding the origins and maintenance of variation in defenses is necessary in building a more complete picture of factors shaping the evolution of aposematic and mimetic systems.

opencc-zeroDec 2018View details →

Data from: Molecular physiology of chemical defenses in a poison frog

Poison frogs sequester small molecule lipophilic alkaloids from their diet of leaf litter arthropods for use as chemical defenses against predation. Although the dietary acquisition of chemical defenses in poison frogs is well-documented, the physiological mechanisms of alkaloid sequestration has not been investigated. Here, we used RNA sequencing and proteomics to determine how alkaloids impact mRNA or protein abundance in the Little Devil Frog (Oophaga sylvatica) and compared wild caught chemically defended frogs to laboratory frogs raised on an alkaloid-free diet. To understand how poison frogs move alkaloids from their diet to their skin granular glands, we focused on measuring gene expression in the intestines, skin, and liver. Across these tissues, we found many differentially expressed transcripts involved in small molecule transport and metabolism, as well as sodium channels and other ion pumps. We then used proteomic approaches to quantify plasma proteins, where we found several protein abundance differences between wild and laboratory frogs, including the amphibian neurotoxin binding protein saxiphilin. Finally, because many blood proteins are synthesized in the liver, we used thermal proteome profiling as an untargeted screen for soluble proteins that bind the alkaloid decahydroquinoline. Using this approach, we identified several candidate proteins that interact with this alkaloid, including saxiphilin. These transcript and protein abundance patterns suggest the presence of alkaloids influences frog physiology and that small molecule transport proteins may be involved in toxin bioaccumulation in dendrobatid poison frogs.

opencc-by-nd-4.0Sep 2016View details →

FIGURE 3 in Attack and defense in a gamasid-oribatid mite predator-prey experiment - sclerotization outperforms chemical repellency

FIGURE 3: Body size and mass of adults and tritonymphs of Archegozetes longisetosus. Stars indicate significant differences (Welch two-sample t-test, ***p<0.001).

opencc-by-nd-4.0Sep 2016View details →

FIGURE 1 in Attack and defense in a gamasid-oribatid mite predator-prey experiment - sclerotization outperforms chemical repellency

FIGURE 1: Consumption [%] of the predatory mite Stratiolaelaps miles feeding on differently treated adults and tritonymphs of Archegozetes longisetosus (armed= control group; disarmed= hexane treated specimens). Stars indicate significant differences (Mann-Whitney-U-test, ***p<0.001).

opencc-by-nd-4.0Sep 2016View details →

FIGURE 2 in Attack and defense in a gamasid-oribatid mite predator-prey experiment - sclerotization outperforms chemical repellency

FIGURE 2: Normalized amount of defensive secretion of attacked and control group Archegozetes longisetosus. Stars indicate significant differences (Mann-Whitney-U-test, ***p<0.001).

opencc-zeroDec 2022View details →

Plant species with higher chemical defenses enhance herbivore cellular immunity with differential effectiveness against two parasitoid species

Insect herbivores simultaneously experience bottom-up effects of plant defensive chemistry and the top-down effects of natural enemies. At the intersection of these effects are herbivore immune systems, herbivore traits that have largely been overlooked in studies of plant-insect interactions. Most previous studies have demonstrated compromised immunity of herbivores that feed on plants with higher defensive chemistry. Many studies have used embedded microfilaments or silica beads as proxies for parasitoid eggs. Yet, parasitoids may evade or suppress host immune responses by injecting venom, calyx fluid, or through modifications of their egg surface structure, necessitating studies that include all three trophic levels to obtain a complete picture of how plant traits may modulate herbivore immunity.Here we examined the effect of host plant species that differ in glucosinolate (anti-herbivore compounds produced by plants in the Brassicaceae) concentrations on the immune status of an herbivore and its consequences for two species of parasitoids with different life history traits.We found that larvae of the butterfly Pieris rapae that fed on field mustard Brassica rapa, which contain 52-fold higher glucosinolate concentrations than collards B. oleracea, attained lower body weights and experienced prolonged development to adulthood.Yet, caterpillars that fed on B. rapa had enhanced cellular immunity, as measured by total and differential hemocyte counts, as well as melanization capacity compared to larvae that fed on B. oleracea.In turn, the likelihood that at least some eggs in clutches of the gregarious endoparasitoid Cotesia glomerata would be encapsulated, leading to a reduction in brood size, were three times greater when their host caterpillars fed on B. rapa compared to B. oleracea. Interestingly, eggs of the solitary endoparasitoid Cotesia rubecula were rarely encapsulated irrespective of the host plant on which their host caterpillar fed. Therefore, our results suggest that plant defense metabolites can influence the expression of herbivore immunity, but the effectiveness of this response strongly depends on the identity of the parasitoid and its ability to evade the caterpillar immune response, and possibly the evolution of these trophic interactions in non-native systems.

opencc-by-4.0Sep 2023View details →

SI_IV_3_Reverse chemical ecology to study the defense of the plant host Sextonia rubra and the chemical mediators of its endophyte Fusarium falciforme against phytopathogen Trametes versicolor

Ces travaux présentant les données supplémentaires générés lors de l'étude de la confrontation d'isolat identifiés comme des Fusarium falciforme contre Trametes versicolor.

publicAug 2019View details →

Data from: Chemical defense over decadal scales: ontogenetic allocation trajectories and consequences for fitness in a foundation tree species

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publicJul 2024View details →

Integration of attractive and defensive phytochemicals is unlikely to constrain chemical diversification in a perennial herb

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