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Life‐history studies are often conducted in a laboratory environment where it is easy to assay individual animals. However, factors such as temperature, photoperiod, and nutrition vary greatly between laboratory and field environments, making it difficult to compare results. Consequently, there is a need to study individual life histories in the field, but this is currently difficult in systems such as Daphnia where it is not possible to mark and track individual animals. Here, we present a proof of principle study showing that field cages are a reliable method for collecting individual‐level life‐history data in Daphnia magna. As a first step, we compared the life history of paired animals reared outside and inside cages to test the hypothesis that cages allow free flow of algal food resources. We then used a seminatural mesocosm setting to compare the performance of individual field cages versus glass jars refilled with mesocosm water each day. We found that cages did not inhibit food flow and that differences in life histories between three clones detected in the jar assays were also detectable using the much less labor‐intensive field cages. We conclude that field cages are a feasible approach for collecting individual‐level life‐history data in systems such as Daphnia where individual animals cannot be marked and tracked. [ABSTRACT FROM AUTHOR]

The switch between aquatic larva and terrestrial adult in the Calopteryx splendens xanthostoma damselfly. It was predicted that each individual would eclose with reduced flight muscle mass and fat reserves compared with those of mature adults. The results help to demonstrate that selection pressures within one odonate life history stage, have a strong effect on individual and offspring traits in other life history stages.

Phosphorus (P) is essential for growth of all organisms, and P content is correlated with growth in most taxa. Although P content was initially considered to be a trait fixed at the species level, there is growing evidence for considerable intraspecific variation. Selection on such variation can thus alter the rates at which P fluxes through food webs.Nevertheless, prior work describing the sources and extent of intraspecific variation in P content were not genetically explicit, confounded by unknown genetic background and evolutionary history. We constructed an F2 recombinant population of the dominant freshwater grazer, Daphnia pulicaria to mitigate such issues.F2 recombinants exhibited considerable variation in growth rate, P content (0.49%–1.97%), P use efficiency (PUE; 51–208 mg biomass/mg P), and correlated traits such as hatching time of resting eggs, in common garden conditions.These results clearly demonstrate the scope of genetic recombination in generating variation in ecologically relevant traits. The absence of environmental selection is a likely component driving such variation not observed in natural settings.Although phosphoglucose isomerase (PGI) genotype was significantly associated with variation in hatching time of resting eggs, contrary to prior work with less rigorous designs, and allelic variation at the PGI locus did not explain variation in P content and PUE of Daphnia, indicating that such quantitative traits are under polygenic control.Together, these results suggest that although there is considerable genetic scope for variation in key ecologically relevant traits, such as P content and efficiency of P use, these traits are likely under strong stabilizing selection, most likely due to selection on growth rate and size. Importantly, our observations suggest that anthropogenic alterations to P supply due to eutrophication could alter selection on these traits, thereby rapidly altering the role Daphnia plays in the P cycle of lakes. [ABSTRACT FROM AUTHOR]

Intergenerational plasticity or parental effects—when parental environments alter the phenotype of future generations—can influence how organisms cope with environmental change. An intriguing, underexplored possibility is that sex—of both the parent and the offspring—plays an important role in driving the evolution of intergenerational plasticity in both adaptive and non‐adaptive ways.Here, we evaluate the potential for sex‐specific parental effects in a freshwater population of three‐spined sticklebacks Gasterosteus aculeatus by independently and jointly manipulating maternal and paternal experiences and separately evaluating their phenotypic effects in sons versus daughters. We tested the adaptive hypothesis that daughters are more responsive to cues from their mother, whereas sons are more responsive to cues from their father.We exposed mothers, fathers or both parents to visual cues of predation risk and measured offspring antipredator traits and brain gene expression.Predator‐exposed fathers produced sons that were more risk‐prone, whereas predator‐exposed mothers produced more anxious sons and daughters. Furthermore, maternal and paternal effects on offspring survival were non‐additive: offspring with a predator‐exposed father, but not two predator‐exposed parents, had lower survival against live predators. There were also strong sex‐specific effects on brain gene expression: exposing mothers versus fathers to predation risk activated different transcriptional profiles in their offspring, and sons and daughters strongly differed in the ways in which their brain gene expression profiles were influenced by parental experience.We found little evidence to support the hypothesis that offspring prioritize their same‐sex parent's experience. Parental effects varied with both the sex of the parent and the offspring in complicated and non‐additive ways. Failing to account for these sex‐specific patterns (e.g. by pooling sons and daughters) would have underestimated the magnitude of parental effects. Altogether, these results draw attention to the potential for sex to influence patterns of intergenerational plasticity and raise new questions about the interface between intergenerational plasticity and sex‐specific selective pressures, sexual conflict and sexual selection. [ABSTRACT FROM AUTHOR]

Transgenerational plasticity (TGP) occurs when the environment encountered by one generation (F0) alters the phenotypes of one or more future generations (e.g. F1 and F2). Sex selective TGP, via specific lineages or to only male or female descendants, has been underexplored in natural systems, and may be adaptive if it allows past generations to fine‐tune the phenotypes of future generations in response to sex‐specific life‐history strategies.We sought to understand if exposing males to predation risk can influence grandoffspring via sperm in three‐spined stickleback Gasterosteus aculeatus. We specifically tested the hypothesis that grandparental effects are transmitted in a sex‐specific way down the male lineage, from paternal grandfathers to F2 males.We reared F1 offspring of unexposed and predator‐exposed F0 males under 'control' conditions and used them to generate F2s with control grandfathers, a predator‐exposed maternal grandfather (i.e. predator‐exposed F0 males to F1 daughters to F2s), a predator‐exposed paternal grandfather (i.e. predator‐exposed F0 males to F1 sons to F2s) or two predator‐exposed grandfathers. We then assayed male and female F2s for a variety of traits related to antipredator defence.We found little evidence that transgenerational effects were mediated to only male descendants via the paternal lineage. Instead, grandpaternal effects depended on lineage and were mediated largely across sexes, from F1 males to F2 females and from F1 females to F2 males. When their paternal grandfather was exposed to predation risk, female F2s were heavier and showed a reduced change in behaviour in response to a simulated predator attack relative to grandoffspring of control, unexposed grandparents. In contrast, male F2s showed reduced antipredator behaviour when their maternal grandfather was exposed to predation risk. However, these patterns were only evident when one grandfather, but not both grandfathers, was exposed to predation risk, suggesting the potential for non‐additive interactions across lineages.If sex‐specific and lineage effects are common, then grandparental effects are likely underestimated in the literature. These results draw attention to the importance of sex‐selective inheritance of environmental effects and raise new questions about the proximate and ultimate causes of selective transmission across generations. [ABSTRACT FROM AUTHOR]

Most animals are visually oriented, and their eyes provide their 'window to the world'. Eye size correlates positively with visual performance, because larger eyes can house larger pupils that increase photon catch and contrast discrimination, particularly under dim light, which have positive effects on behaviours that enhance fitness, including predator avoidance and foraging.Recent studies have linked predation risk to selection for larger eyes and pupils, and such changes should be of importance for the majority of teleost fishes as they have a pupil that is fixed in size (eyes lack a pupillary sphincter muscle) and, hence, do not respond to changes in light conditions.Here, we quantify eye and pupil size of individual crucian carp, a common freshwater fish, following controlled manipulations of perceived predation risk (presence/absence). We also tested if crucian carp responded to increased predation risk by shifts in diel activity patterns.We found that crucian carp show phenotypic plasticity with regards to pupil size, but not eye size, as pupil size increased when exposed to predators (pike). Predator‐exposed crucian carp also shifted from diurnal to nocturnal activity. Using a modelling exercise, we moreover show that the plastically enlarged pupils significantly increase visual range, especially for small objects under dim light conditions.Overall, our results provide compelling evidence for predator‐induced pupil enlargement resulting in enhanced visual capabilities in a teleost fish. Pupil size plasticity in combination with the observed shift towards nocturnal activity may allow for efficient foraging also under dark conditions when predation risk from diurnal and visually oriented predators is reduced. The data highlight the powerful role of predation risk for eye development and evolution. [ABSTRACT FROM AUTHOR]

Understanding how genetic, nongenetic, and environmental cues are integrated during development may be critical in understanding if, and how, organisms will respond to rapid environmental change. Normally, only post‐embryonic studies are possible. But in this study, we developed a real‐time, high‐throughput confocal microscope assay that allowed us to link Daphnia embryogenesis to offspring life history variation at the individual level. Our assay identified eight clear developmental phenotypes linked by seven developmental stages, the duration of which were correlated with the expression of specific offspring life history traits. Daphnia embryogenesis varied not only between clones reared in the same environment, but also within a single clone when mothers were of different ages or reared in different food environments. Our results support the hypothesis that Daphnia embryogenesis is plastic and can be altered by changes in maternal state or maternal environment. As well as furthering our understanding of the mechanisms underpinning parental effects, our assay may also have an industrial application if it can be used as a rapid ecotoxicological prescreen for testing the effect that pollutant doses have on offspring life histories traditionally assayed with a 21‐day Daphnia reproduction test. Research Highlights: We use a confocal microscope assay to demonstrate that embryogenesis varies not only between Daphnia clones, but also within a clone when mothers are of different ages or they have experienced different food environments. [ABSTRACT FROM AUTHOR]

Sex‐biased dispersal (SBD) often skews the local sex ratio in a population. This can result in a shortage of mates for individuals of the less‐dispersive sex. Such mate limitation can lead to Allee effects in populations that are small or undergoing range expansion, consequently affecting their survival, growth, stability and invasion speed.Theory predicts that mate shortage can lead to either an increase or a decrease in the dispersal of the less‐dispersive sex. However, neither of these predictions have been empirically validated.To investigate how SBD‐induced mate limitation affects dispersal of the less‐dispersive sex, we used Drosophila melanogaster populations with varying dispersal propensities. To rule out any mate‐independent density effects, we examined the behavioural plasticity of dispersal in the presence of mates as well as same‐sex individuals with differential dispersal capabilities.In the presence of high‐dispersive mates, the dispersal of both male and female individuals was significantly increased. However, the magnitude of this increase was much larger in males than in females, indicating that the former shows greater mate‐finding dispersal. Moreover, the dispersal of either sex did not change when dispersing alongside high‐ or low‐dispersive individuals of the same sex. This suggested that the observed plasticity in dispersal was indeed due to mate‐finding dispersal, and not mate‐independent density effects.Strong mate‐finding dispersal can diminish the magnitude of sex bias in dispersal. This can modulate the evolutionary processes that shape range expansions and invasions, depending on the population size. In small populations, mate‐finding dispersal can ameliorate Allee effects. However, in large populations, it can dilute the effects of spatial sorting. [ABSTRACT FROM AUTHOR]

Camouflage helps animals to hide from predators and is therefore key to survival. Although widespread convergence of animal phenotypes to their natural environment is well‐established, there is a lack of knowledge about how species compromise camouflage accuracy across different background types in their habitat.Here we tested how background matching has responded to top–down selection by avian and mammalian predators using Sahara–Sahel desert rodents in North Africa.We show that the fur colouration of several species has become an accurate match to different types of desert habitats. This is supported by a correlation analysis of colour and pattern metrics, investigation of animal‐to‐background similarities at different spatial scales and is confirmed by modelling of two predator vision systems.The background match was closest across large (or global) spatial scales, suggesting a generalist camouflage tactic for many background types. Some species, may have a better match to the background over small (or focal) spatial scales, which could be the result of habitat choices or differential predation. Nevertheless, predicted discrimination distances of fur colouration were virtually indistinguishable for mammalian and low for avian vision model, which implies effective camouflage.Our study provides one of the best documented cases of multilevel camouflage accuracy in geographically widespread taxa. We conclude that background matching has become an effective and common adaptation against predatory threat in Sahara–Sahelian desert rodents. [ABSTRACT FROM AUTHOR]

The importance of microbial and plant communities in the control of the diversity and structure of soil animal communities has been clarified over the last decade. Previous research focused on abiotic factors, niche separation and spatial patterns. Significant gaps still exist in our knowledge of the factors that control the stability of these communities over time.We analysed a 9‐year dataset from the national Long‐term Ecological Research Network of Latvia. We focused on 117 oribatid species from three Scots pine forests of different age (<40, 65 and >150 years) and structure. For each forest type, 100 samples were collected each year, providing very high replication and long time series for a soil community. We assessed different aspects of stability: we used a dynamic null model, parameterized on observed growth rates, to test the hypothesis that asynchrony in species populations stabilizes total community size; we also analysed alpha and beta diversity over time to test the hypothesis that temporal variation in species composition and relative abundances is controlled by forest attributes.Real communities can be more stable than their stochastic counterparts if species are asynchronous, confirming for the first time the role of asynchrony in stabilizing soil communities. Yet, while some real communities were more stable and had higher abundance and growth rates than others, they were not necessarily more asynchronous than the less stable communities. Species composition and relative abundances were also less variable in the more stable communities.Species asynchrony generally stabilizes species‐rich communities but is not sufficient to explain the different levels of stability between forests. Forest age is a key factor explaining the different levels of overyielding and so stability. Data suggest that both asynchrony and high diversity of microhabitat structure of Scots pine forests promote the stability of soil animal communities. [ABSTRACT FROM AUTHOR]

Many tropical environments experience cyclical seasonal changes, frequently with pronounced wet and dry seasons, leading to a highly uneven temporal distribution of resources. Short‐lived animals inhabiting such environments often show season‐specific adaptations to cope with alternating selection pressures.African Bicyclus butterflies show strong seasonal polyphenism in a suite of phenotypic and life‐history traits, and their adults are thought to undergo reproductive diapause associated with the lack of available larval host plants during the dry season.Using 3 years of longitudinal field data for three species in Malawi, dissections demonstrated that one forest species reproduces continuously, whereas two savannah species undergo reproductive diapause in the dry season, either with or without pre‐diapause mating. Using additional data from field‐collected and museum samples, we then documented the same three mating strategies for a further 37 species.Phylogenetic analyses indicated that the ancestral state was a non‐diapausing forest species, and that habitat preference and mating strategy evolved in a correlated fashion.Bicyclus butterflies underwent rapid diversification during the Late Miocene, coinciding with expansions into more open savannah habitat. We conclude that the ability to undergo reproductive diapause was a key trait that facilitated colonization and eventual radiation into savannahs in the Late Miocene. [ABSTRACT FROM AUTHOR]

Trait‐based studies are needed to understand the plastic and genetic responses of organisms to warming. A neglected organismal trait is elemental composition, despite its potential to cascade into effects on the ecosystem level.Warming is predicted to shape elemental composition through shifts in storage molecules associated with responses in growth, body size and metabolic rate. Our goals were to quantify thermal response patterns in body composition and to obtain insights into their underlying drivers and their evolution across latitudes.We reconstructed the thermal response curves (TRCs) for body elemental composition [C (carbon), N (nitrogen) and the C:N ratio] of damselfly larvae from high‐ and low‐latitude populations. Additionally, we quantified the TRCs for survival, growth and development rates and body size to assess local thermal adaptation, as well as the TRCs for metabolic rate and key macromolecules (proteins, fat, sugars and cuticular melanin and chitin) as these may underlie the elemental TRCs.All larvae died at 36°C. Up to 32°C, low‐latitude larvae increased growth and development rates and did not suffer increased mortality. Instead, growth and development rates of high‐latitude larvae were lower and levelled off at 24°C, and mortality increased at 32°C. This latitude‐associated thermal adaptation pattern matched the 'hotter‐is‐better' hypothesis. With increasing temperatures, low‐latitude larvae decreased C:N, while high‐latitude larvae increased C:N. These patterns were driven by associated changes in N contents, while C contents did not respond to temperature. Consistent with the temperature‐size rule and the thermal melanism hypothesis, body size and melanin levels decreased with warming. While all traits and associated macromolecules (except for metabolic rate that showed thermal compensation) assumed to underlie thermal responses in elemental composition showed thermal plasticity, these were largely independent and none could explain the stoichiometric TRCs.Our results highlight that thermal responses in elemental composition cannot be explained by traditionally assumed drivers, asking for a broader perspective including the thermal dependence of elemental fluxes. Another key implication is that thermal evolution can reverse the plastic stoichiometric thermal responses and hence reverse how warming may shape food web dynamics through changes in body composition at different latitudes. [ABSTRACT FROM AUTHOR]

Numerous studies have demonstrated that dispersal is dependent on both disperser phenotype and the local environment. However, there is substantial variability in the observed strength and direction of phenotype‐ and environment‐dependent dispersal. This has been hypothesized to be the result of interactive effects among the multiple phenotypic and environmental factors that influence dispersal.Here, our goal was to test the hypothesis that these interactions are responsible for generating variation in dispersal behaviour.We achieved these goals by conducting a large, 2‐year, mark–release–recapture study of the backswimmer Notonecta undulata in an array of 36 semi‐natural ponds. We measured the effects of multiple phenotypic (sex and body size) and environmental (population density and sex ratio) factors, on both dispersal probability and dispersal distance.We found support for the hypothesis that interactive effects influence dispersal and produce variability in phenotype‐ and environment‐dependent dispersal: dispersal probability was dependent on the three‐way interaction between sex, body mass and population density. Small males displayed strong, positive density dependence in their dispersal behaviour, while large males and females overall did not respond strongly to density. Small notonectids, regardless of sex, were more likely to disperse, but this effect was strongest at high population densities. Finally, the distance dispersed by backswimmers was a negative function of population density, a pattern which we hypothesize could be related to: (a) individuals from high and low density patches having different dispersal strategies, or (b) the effect of density on dispersal capacity.These results suggest that phenotype‐by‐environment interactions strongly influence dispersal. Since phenotype‐ and environment‐dependent dispersal has different consequences for ecological and evolutionary dynamics (e.g. metapopulation persistence and local adaptation) than random dispersal, interactive effects may have wide‐reaching impacts on populations and communities. We therefore argue that more investment should be made into estimating the effects of multiple, interacting factors on dispersal and determining whether similar interactive effects are acting across systems. [ABSTRACT FROM AUTHOR]

Cryptic pigmentation of prey is often thought to evolve in response to predator‐mediated selection, but pigmentation traits can also be plastic, and change with respect to both abiotic and biotic environmental conditions. In such cases, identifying the presence of, and drivers of trait plasticity is useful for understanding the evolution of crypsis.Previous work suggests that cryptic pigmentation of freshwater isopods (Asellus aquaticus) has evolved in response to predation pressure by fish in habitats with varying macrophyte cover and coloration. However, macrophytes can potentially influence the distribution of pigmentation by altering not only habitat‐specific predation susceptibility, but also dietary resources and abiotic conditions. The goals of this study were to experimentally test how two putative agents of selection, namely macrophytes and fish, affect the pigmentation of A. aquaticus, and to assess whether pigmentation is plastic, using a diet manipulation in a common garden.We performed two experiments: (a) in an outdoor mesocosm experiment, we investigated how different densities of predatory fish (0/30/60 three‐spined stickleback [Gasterosteus aculeatus] per mesocosm) and macrophytes (presence/absence) affected the abundance, pigmentation and body size structure of isopod populations. (b) In a subsequent laboratory experiment, we reared isopods in a common garden experiment on two different food sources (high/low protein content) to test whether variation in pigmentation of isopods can be explained by diet‐based developmental plasticity.We found that fish presence strongly reduced isopod densities, particularly in the absence of macrophytes, but had no effect on pigmentation or size structure of the populations. However, we found that isopods showed consistently higher pigmentation in the presence of macrophytes, regardless of fish presence or absence. Our laboratory experiment, in which we manipulated the protein content of the isopods' diet, revealed strong plasticity of pigmentation and weak plasticity of growth rate.The combined results of both experiments suggest that pigmentation of A. aquaticus is a developmentally plastic trait and that multiple environmental factors (e.g. macrophytes, diet and predation) might jointly influence the evolution of cryptic pigmentation of A. aquaticus in nature on relatively short time‐scales. This paper combines laboratory and outdoor experiments, as well as data from previous fieldwork to uncover phenotypic variation from the individual to the population level. The authors show that differences in plant cover, as well as diet quality, can lead to substantial variation in pigmentation of Asellus aquaticus. [ABSTRACT FROM AUTHOR]

Stressful environments affect life-history components of fitness through (i) instantaneous detrimental effects, (ii) historical (carry-over) effects and (iii) history-by-environment interactions, including acclimation effects. The relative contributions of these different responses to environmental stress are likely to change along life, but such ontogenic perspective is often overlooked in studies of tolerance curves, precluding a better understanding of the causes of costs of acclimation, and more generally of fitness in temporally fine-grained environments. We performed an experiment in the brine shrimp Artemia to disentangle these different contributions to environmental tolerance, and investigate how they unfold along life. We placed individuals from three clones of A. parthenogenetica over a range of salinities during a week, before transferring them to a (possibly) different salinity for the rest of their lives. We monitored individual survival at repeated intervals throughout life, instead of measuring survival or performance at a given point in time, as commonly done in acclimation experiments. We then designed a modified survival analysis model to estimate phase-specific hazard rates, accounting for the fact that individuals may share the same treatment for only part of their lives. Our approach allowed us to distinguish effects of salinity on (i) instantaneous mortality in each phase (habitat quality effects), (ii) mortality later in life (history effects) and (iii) their interaction. We showed clear effects of early salinity on late survival and interactions between effects of past and current environments on survival. Importantly, analysis of the ontogenetic dynamics of the tolerance curve reveals that acclimation affects different parts of the curve at different ages. Adopting a dynamical view of the ontogeny of tolerance curve should prove useful for understanding niche limits in temporally changing environments, where the full sequence of environments experienced by an individual determines its overall environmental tolerance, and how it changes throughout life. [ABSTRACT FROM AUTHOR]

Due to climate change, Arctic ice sheets are retreating. This leads to the formation of numerous new periglacial ponds and lakes, which are being colonized by planktonic organisms such as the water flea Daphnia. This system provides unique opportunities to test genotype colonization dynamics and the genetic assemblage of populations. Here, we studied clonal richness of the Daphnia pulex species complex in novel periglacial habitats created by glacial retreat in the Jakobshavn Isbræ area of western Greenland., Along a 10 km transect, we surveyed 73 periglacial habitats out of which 61 were colonized by Daphnia pulex. Hence, for our analysis, we used 21 ponds and 40 lakes in two clusters of habitats differing in age (estimated <50 years vs. >150 years). We tested the expectation that genetic diversity would be low in recently formed (i.e. young), small habitats, but would increase with increasing age and size., We identified a total of 42 genetically distinct clones belonging to two obligately asexual species of the D. pulex species complex: D. middendorffiana and the much more abundant D. pulicaria. While regional clonal richness was high, most clones were rare: 16 clones were restricted to a single habitat and the five most widespread clones accounted for 68% of all individuals sampled. On average, 3·2 clones (range: 1-12) coexisted in a given pond or lake. There was no relationship between clonal richness and habitat size when we controlled for habitat age. Whereas clonal richness was statistically higher in the cluster of older habitats when compared with the cluster of younger ponds and lakes, most young habitats were colonized by multiple genotypes., Our data suggest that newly formed (periglacial) ponds and lakes are colonized within decades by multiple genotypes via multiple colonization events, even in the smallest of our study systems (4 m2). [ABSTRACT FROM AUTHOR]

Population density has recently been suggested to be an important factor influencing metabolic rates and to represent an important 'third axis' explaining variation beyond that explained by body mass and temperature. In situations where population density influences food consumption, the immediate effect on metabolism acting through specific dynamic action ( SDA), and downregulation due to fasting over longer periods, is well understood. However, according to a recent review, previous studies suggest a more general effect of population density per se, even in the absence of such effects. It has been hypothesized that this results from animals performing anticipatory responses (i.e. reduced activity) to expected declines in food availability., Here, we test the generality of this finding by measuring density effects on metabolic rates in 10 clones from two different species of the zooplankton Daphnia ( Daphnia pulex Leydig and D. magna Straus). Using fluorescence-based respirometry, we obtain high-precision measures of metabolism., We also identify additional studies on this topic that were not included in the previous review, compare the results and evaluate the potential for measurement bias in all previous studies., We demonstrate significant variation in mass-specific metabolism among clones within both species. However, we find no evidence for a negative relationship between population density and mass-specific metabolism. The previously reported pattern also disappeared when we extended the set of studies analysed., We discuss potential reasons for the discrepancy among studies, including two main sources of potential bias (microbial respiration and declining oxygen consumption due to reduced oxygen availability). Only one of the previous studies gives sufficient information to conclude the absence of such biases, and consistent with our results, no effect of density on metabolism was found. We conclude that population density per se does not have a general effect on mass-specific metabolic rate. [ABSTRACT FROM AUTHOR]

Foraging modalities (e.g. passive, sit-and-wait, active) and traits are plastic in some species, but the extent to which this plasticity affects interspecific competition remains unclear., Using a long-term laboratory mesocosm experiment, we quantified competition strength and the plasticity of foraging traits in a guild of generalist predators of arthropods with a range of foraging modalities., Each mesocosm contained eight passively foraging pink sundews, and we employed an experimental design where treatments were the presence or absence of a sit-and-wait foraging spider and actively foraging toad crossed with five levels of prey abundance. We hypothesized that actively foraging toads would outcompete the other species at low prey abundance, but that spiders and sundews would exhibit plasticity in foraging traits to compensate for strong competition when prey were limited., Results generally supported our hypotheses. Toads had a greater effect on sundews at low prey abundances, and toad presence caused spiders to locate webs higher above the ground. Additionally, the closer large spider webs were to the ground, the greater the trichome densities produced by sundews. Also, spider webs were larger with than without toads and as sundew numbers increased, and these effects were more prominent as resources became limited. Finally, spiders negatively affected toad growth only at low prey abundance., These findings highlight the long-term importance of foraging modality and plasticity of foraging traits in determining the strength of competition within and across taxonomic kingdoms. Future research should assess whether plasticity in foraging traits helps to maintain coexistence within this guild and whether foraging modality can be used as a trait to reliably predict the strength of competitive interactions. [ABSTRACT FROM AUTHOR]