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openCC (other)May 2017View details →

Data describing how four different levels of induced plant defenses change cannibalism among larval lepidopterans and alter consumption of plant tissue by larval lepidopterans.

A dataset comprised of three experiments: Experiment 1. Data describing how four different levels of induced plant defenses change cannibalism among larval lepidopterans and alter consumption of plant tissue by larval lepidopterans. The experiment was conducted at UW-Madison in Birge Hall. Experiment 2. Data describing how two levels of induced plant defenses and two levels of food provision (presence or absence of dead conspecifics) changes cannibalism, herbivory, and growth among larval lepidopterans. Experiment 3. Data describing mass loss of tomato leaves that were clipped and allowed to dry for two days. These data are to determine estimates of natural (autogenic) weight loss due to evaporation for comparison of weight loss due to herbivory and evaporation as part of feeding trials with armyworms (see other two associated datasets in this series). The experiment was conducted at the Department of Biology at Virginia Commonwealth University.

Interpreting the smells of predation: How alarm cues and kairomones induce different prey defenses.

1. For phenotypically plastic organisms to produce phenotypes that are well matched to their environment, they must acquire information about their environment. For inducible defences, cues from damaged prey and cues from predators both have the potential to provide important information, yet we know little about the relative importance of these separate sources of information for behavioural and morphological defences. We also do not know the point during a predation event at which kairomones are produced, i.e. whether they are produced constitutively, during prey attack or during prey digestion. 2. We exposed leopard frog tadpoles (Rana pipiens) to nine predator cue treatments involving several combinations of cues from damaged conspecifics or heterospecifics, starved predators, predators only chewing prey, predators only digesting prey or predators chewing and digesting prey. 3. We quantified two behavioural defences. Tadpole hiding behaviour was induced only by cues from crushed tadpoles. Reduced tadpole activity was induced only by cues from predators digesting tadpoles or predators chewing + digesting tadpoles. 4. We also quantified tadpole mass and two size-adjusted morphological traits that are known to be phenotypically plastic. Mass was unaffected by the cue treatments. Relative body length was affected (i.e. there were differences among some treatments), but none of the treatments significantly differed from the no-predator control. Relative tail depth was affected by the treatments and deeper tails were induced only when tadpoles were exposed to cues from predators digesting tadpoles or cues from predators chewing + digesting tadpoles. 5. These results demonstrate that some prey species can discriminate among a diverse set of potential cues from heterospecific prey, conspecific prey and predators. Moreover, the results illustrate that the cues responsible for the full suite of behavioural and morphological defences are not induced by tadpole crushing nor

The heritability of inducible defenses in tadpoles.

The evolution of plastic traits requires phenotypic trade-offs and heritable traits, yet the latter requirement has received little attention, especially for predatorinduced traits. Using a half-sib design, I examined the narrow-sense heritability of predator-induced behaviour, morphology, and life history in larval wood frogs (Rana sylvatica). Many of the traits had significant additive genetic variation in predator (caged Anax longipes) and no-predator environments. Whereas most traits had moderate to high heritability across environments, tail depth exhibited high heritability with predators but low heritability without predators. In addition, several traits had significant heritability for plasticity, suggesting a potential for selection to act on plasticity per se. Genetic correlations confirmed known phenotypic relationships across environments and identified novel relationships within each environment. This appears to be the first investigation of narrow-sense heritabilities for predator-induced traits and confirms that inducible traits previously shown to be under selection also have a genetic basis and should be capable of exhibiting evolutionary responses.

Damage, digestion, and defense: The roles of alarm cues and kairomones for inducing prey defenses.

Inducible defences are widely used for studying phenotypic plasticity, yet frequently we know little about the cues that induce these defences. For aquatic prey, defences are induced by chemical cues from predators (kairomones) and injured prey (alarm cues). Rarely has anyone determined the separate and combined effects of these cues, particularly across phylogenetically diverse prey types. We examined how tadpoles (Hyla versicolor) altered their defences when 10 different prey were either crushed by hand or consumed by predators. Across all prey types, crushing induced only a subset of the defences induced by consumption. Consuming vs. crushing produced additive responses for behaviour but synergistic responses for morphology and growth. Moreover, we discovered the first extensive evidence that prey responses to different alarm cues depends on prey phylogeny. These results suggest that the amount of information available to the prey affects both the quantitative and qualitative nature of the defended phenotype.

Having the guts to compete: How intestinal plasticity explains costs of inducible defenses.

Predators commonly induce phenotypic changes that make prey better at surviving predation at the cost of reduced growth. While we have a good understanding of how trait changes affect predation risk, we lack a mechanistic understanding of why predatorinduced phenotypes differ in growth. Using two mesocosm experiments, we combined phenotypic plasticity theory with predictions from optimal digestion theory to demonstrate that intra- and interspecific competition induced relatively long guts while predators induced relatively short guts. The longer guts induced by competition appear to be an adaptive response that allows more efficient digestion and more rapid growth whereas the shorter guts induced by predators appear to result from a tradeoff of building larger tails in predator environments at the cost of smaller bodies. By combining these two bodies of theory, we now have a much better understanding of the mechanisms that cause the phenotypic trade-offs that select for inducible defences.

opencc-by-4.0Jul 2019View details →

Transgenerational plasticity of inducible defenses: combined effects of grand-parental, parental and current environments - PDF, datasets and R script

PDF, dataset and R script for the paper: Tariel J, Plénet S, & Luquet E. Transgenerational plasticity of inducible defenses: combined effects of grand-parental, parental and current environments.  Two data sets are provided: one for the analysis of the behavior (dataBehaviour.csv) and one for the analysis of other variables (weight, shell thickness and morphology; dataMorphology.csv). There are analyzed in the same R script (Script_TARIEL-Juliette.R) Signification of variables names: G1: treatment/environment of the grand-parental generation (control C or with predator-cue P) G2: treatment/environment of the parental generation (control C or with predator-cue P) G3: treatment/environment of the offspring generation (control C or with predator-cue P) Family: unique ID for each family Individual: number to identify siblings within a family  ID: unique ID for each individual  W: snail total weight (g) Th: shell thickness (mm) L: shell length (mm) l: shell width (mm) Lo: aperture length (mm) lo: aperture width (mm) crawlout : position of the snail (0:  below the water surface; 1: above/on the water surface) Day : day of measurement (crawling-out behaviour was measured three times through three consecutives days d2, d3 and d4)

opencc-by-4.0Jan 2023View details →

data for paper: Predator-induced defense decreases growth rate and photoprotective capacity in a nitrogen-limited dinoflagellate

this is the data for paper "Predator-induced defense decreases growth rate and photoprotective capacity in a nitrogen-limited dinoflagellate"

Fig. 6 in Multiple infestations induce direct defense of maize to Tetranychus urticae (Acari: Tetranychidae)

Fig. 6. Number (mean ± SE) of live females (A, C2 = 7.39; df = 37; P <0.001), immature individuals (B, C2 = 2.14; df = 36; P <0.001), eggs (C, C2 = 2.14; df = 36; P <0.001), and dead females (D, C2 = 7.7; df = 36; P <0.001) of the two-spotted spider mite Tetranychus urticae on conspecific plus Spodoptera frugiperda infested conventional (white bars) and Bt (gray bars) maize plants. M = mite, C = caterpillar. *** = statistically significant (P <0.01).

Fig. 5 in Multiple infestations induce direct defense of maize to Tetranychus urticae (Acari: Tetranychidae)

Fig. 5. Number (mean ± SE) of live females (A, C2 = 29.5; df =37; P = 0.195), immature individuals (B, C2 = 39.1; df = 36; P = 0.670), eggs (C, C2 = 31.7; df = 36; P = 0.326), and dead females (D, C2 = 22.0; df = 37; P = 0.024) of the two-spotted spider mite Tetranychus urticae on conspecific (white bars) and conspecific plus Spodoptera frugiperda infested (gray bars) Bt maize plants. M = mite, C = caterpillar. ns = statistically insignificant, * = statistically significant (P <0.05).

Fig. 4 in Multiple infestations induce direct defense of maize to Tetranychus urticae (Acari: Tetranychidae)

Fig. 4. Number (mean ± SE) of live females (A, C2 = 7.65; df = 37; P <0.001), immature individuals (B, C2 = 2.60; df = 36; P <0.001), eggs (C, C2 = 2.14; df = 36; P <0.001), and dead females (D, C2 = 5.38; df = 37; P <0.001) of the two-spotted spider mite Tetranychus urticae on conspecific (white bars) and conspecific plus Spodoptera frugiperda infested (gray bars) conventional maize plants. M = mite, C = caterpillar. *** = statistically significant (P <0.01).

Fig. 3 in Multiple infestations induce direct defense of maize to Tetranychus urticae (Acari: Tetranychidae)

Fig. 3. Number (mean ± SE) of live females (A, C2 = 31.11; df = 37; P = 0.259), immature individuals (B, C2 = 27.67; df = 37; P = 0.133), eggs (C, C2 = 27.67; df = 36; P = 0.240), and dead females (D, C2 = 23.58; df = 37; P = 0.042) of the two-spotted spider mite Tetranychus urticae on infested conventional (30F35) (white bars) and Bt (30F35Hx) (gray bars) maize plants. ns = statistically insignificant, * = statistically significant (P <0.05).

Fig. 1 in Multiple infestations induce direct defense of maize to Tetranychus urticae (Acari: Tetranychidae)

Fig. 1. Number (mean ± SE) of live females (A, C2 = 45.2; df = 36; P = 0.861), immature individuals (B, C2 = 38.7; df = 37; P = 0.608), eggs (C, C2 = 38.1; df = 36; P = 0.624), and dead females (D, C2 = 29.7; df = 37; P = 0.203) of the two-spotted spider mite Tetranychus urticae on clean (white bars) and co-specific re-infested (gray bars) conventional maize plants (30F35). ns = statistically insignificant.

Fig. 7 in Multiple infestations induce direct defense of maize to Tetranychus urticae (Acari: Tetranychidae)

Fig. 7. Projection to principal component analysis based on the ions detected by electrospray ionization mass spectrometry of uninfested (C = o) and infested with Tetranychus urticae (C + Tu = ●) conventional maize; uninfested (Bt = Z) and infested with T. urticae (Bt + Tu = ■) Bt maize; infested with T. urticae and Spodoptera frungiperda (C + Tu + Sf = Δ) conventional maize; and infested with T. urticae and S. frungiperda (Bt + Tu + Sf = ▲) Bt maize, using the first 2 principal components (Dim) with explained variance in brackets

Fig. 2 in Multiple infestations induce direct defense of maize to Tetranychus urticae (Acari: Tetranychidae)

Fig. 2. Number (mean ± SE) of live females (A, C2 = 21.9; df = 37; P = 0.02), immature individuals (B, C2 = 40.9; df = 37; P = 0.698), eggs (C, C2 = 30.5; df = 37; P = 0.235), and dead females (D, C2 = 21.9; df = 37; P = 0.383) of the two-spotted spider mite, Tetranychus urticae, on clean (light gray bars) and co-specific re-infested (dark gray bars) Bt maize plants (30F35Hx). ns = statistically insignificant, * = statistically significant (P <0.05).

opencc-by-4.0Aug 2023View details →

Molecular, biochemical and metabolomics analyses reveal constitutive and pathogen-induced defense responses of two sugarcane contrasting genotypes against leaf scald disease

Leaf scald caused by the bacteria Xanthomonas albilineans is one of the major concerns to sugarcane production. To breed for resistance, mechanisms underlying plant-pathogen interaction need deeper investigations. Herein, we evaluated sugarcane defense responses against X. albilineans using molecular and biochemical approaches to assess pathogen-triggered ROS, phytohormones and metabolomics in two contrasting sugarcane genotypes from 0.5-144 h post-inoculation (hpi). In addition, the infection process was monitored using TaqMan-based quantification of X. albilineans and the disease symptoms were evaluated in both genotypes after 15 d post-inoculation (dpi) The susceptible genotype presented a response to the infection at 0.5 hpi, accumulating defense-related metabolites such as phenolics and flavonoids with no significant defense responses thereafter, resulting in typical symptoms of leaf scald at 15 dpi. The resistant genotype did not respond to the infection at 0.5 hpi but constitutively presented higher levels of salicylic acid and of the same metabolites induced by the infection in the susceptible genotype. Moreover, two subsequent pathogen-induced metabolic responses at 12 and 144 hpi were observed only in the resistant genotype in terms of amino acids, quinic acids, coumarins, polyamines, flavonoids, phenolics and phenylpropanoids together with an increase of hydrogen peroxide, ROS-related genes expression, indole-3-acetic-acid and salicylic acid. Multilevel approaches revealed that constitutive chemical composition and metabolic reprogramming hampers the development of leaf scald at 48 and 72 hpi, reducing the disease symptoms in the resistant genotype at 15 dpi. Phenylpropanoid pathway is suggested as a strong candidate marker for breeding sugarcane resistant to leaf scald.

opencc-zeroAug 2020View details →

Data from: Tradeoffs affect the adaptive value of plasticity: Stronger cannibal-induced defenses incur greater costs in toad larvae

Adaptive developmental plasticity allows individuals to match their phenotype with their environment, which can increase fitness where threats are inconsistently present. Because adaptive traits are not ubiquitously nor infinitely plastic, tradeoffs between benefits and costs or limits are theoretically necessary to constrain plastic responses. Systems in which extreme risk can be reliably detected are ideal for investigating mechanisms that constrain plasticity, as even costly responses may be adaptive where risk is severe. Cane toads (Rhinella marina) are abundant in Australia and produce large clutches (frequently >10,000 eggs), but asynchronous breeding and rapid development result in variable larval densities within breeding pools. In the field, we found that cannibalism by older cohorts often reduces the survival of conspecific eggs and newly hatched pre-feeding larvae ("hatchlings") by >99%, as feeding larvae ("tadpoles") use chemical cues from the relatively immobile hatchlings to locate and consume them. After hatchlings become free-swimming, however, they are safe from cannibalism. Hatchlings can reduce this period of vulnerability by accelerating development when they detect conspecific tadpole cues. However, this developmental acceleration decreases initial tadpole mass, reduces subsequent survival, growth, and development, affects behavior, and compromises feeding structures. Reaction norms differ among clutches, and greater developmental acceleration is followed by greater impairment of larval function in plastic clutches, whereas nonresponsive clutches are unaffected by exposure to cannibal cues. More plastic clutches ultimately exhibit both poorer performance and greater variation among siblings in exposed and (to a lesser degree) control treatments. Variation among clutches in tadpole viability is driven by differences in plasticity rather than phenotype; fitness reductions are linked to developmental acceleration, not rapid development per se. Clutches with intrinsically slow pre-feeding developmental rates exhibit stronger acceleration (i.e., steeper reaction norms), but clutches with intrinsically rapid development reach invulnerable stages more quickly than those that accelerate development. As a result, high cannibalism risk may favor canalized rapid development rather than facultative developmental acceleration. Cannibalism plays an important role in the recruitment of this invasive species, and hatchling defenses against this threat demonstrate how the limits and tradeoffs associated with an inducible defense can favor canalized defenses over phenotypic plasticity.

opencc-zeroNov 2019View details →

Data from: Induced phenological avoidance: a neglected defense mechanism against seed predation in plants

1. Flowering phenology is an important life history trait affecting plant reproductive performance and is influenced by various abiotic and biotic factors. Pre-dispersal seed predation and pollination are expected to impose counteracting selection pressure on flowering phenology, with pre-dispersal seed predation expected to favor off-peak flowering and pollination to favor synchronous flowering. 2. Here we studied the effect of pre-dispersal seed predation by the beetle Byturus ochraceus, a specialist seed herbivore, on the flowering phenology of Geum urbanum. This forest understorey plant species is self-pollinating, so that the influence of seed predation can be studied independent from pollination. We measured in detail the timing and predation rate of individual flowers during two consecutive years in more than 60 individuals. We tested the hypotheses that pre-dispersal seed predation exerts selection for within-season compensatory flowering as well as for induced phenological avoidance in the following season. 3. We found no indication for compensatory flowering within a growing season, but plants that experienced predation shifted their flowers to the end of the flowering season the subsequent year. This induced phenological avoidance points to a plastic response to pre-dispersal seed predation that may be adaptive. Importantly, the delay in flower production came at a cost, since flowers later in the season had a reduced seed output, presumably because of increasing light limitation following forest canopy closure. 4. Synthesis: Herbivory by specialist enemies can cause serious fitness decline in hosts. We here show that induced shifts in phenology can form an important defense strategy against pre-dispersal seed predation. The induced mismatches between herbivore and host phenology are anticipated to be adaptive when herbivory is predictable across successive flowering periods.

opencc-zeroDec 2016View details →

Data from: Context-dependent defences in turtle ants: resource defensibility and threat level induce dynamic shifts in soldier deployment

1. Induced defences involve the dynamic deployment of limited and specialized defensive resources across multiple locations, to maximize organismal defensive function and fitness. They have been studied intensively in plants and solitary animals, but the induced defences of complex animal societies are poorly understood by comparison, despite the coordinated defensive actions of these taxa. 2. Here, we ask whether the level of environmental danger induces shifts in the deployment of limited and morphologically specialized soldiers across multiple nests in colonies of the turtle ant Cephalotes rohweri. Specifically, we test whether less defensible nests induce greater soldier deployment, and whether elevated enemy threat induced further increases in deployment, or reduced deployment consistent with a risk-limiting strategy. 3. We used colony-collection data to provide natural ecological context to our experiments, a field experiment to address how nest-entrance defensibility and soldier number impact defensive performance, and laboratory experiments to test whether differences in nest defensibility and threat level induce dynamic shifts in soldier deployment to new nests. 4. Less defensible nests were lost rapidly in our field experiment, irrespective of soldier number, but soldier deployment significantly increased survivorship of more defensible nests. Concordantly, less defensible nests induced the deployment of more soldiers per nest under low threat in laboratory experiments. Nevertheless, high-threat conditions revealed a risk-limiting soldier deployment strategy: with more danger, the number of soldiers per nest was significantly reduced in less defensible nests, as was the overall number of new soldier-defended nests. Total deployment to new nests was also consistently lower under high threat, dropping from 40% to 30% across colonies. 5. Induced soldier-based defences in turtle ants are therefore context-dependent, and dynamically scaled back at multiple levels when the environment is more dangerous. This dynamic, risk-limiting strategy is in strong contrast to stable patterns of soldier production in ants, and to typical task-allocation dynamics in members of the worker caste. Moreover, these findings establish that the evolution of specialized defensive agents can be coupled with sophisticated and inducible deployment strategies in complex social taxa, as we see for organisms at other levels of biological complexity.