Find research datasets worth reusing

Sex differences in the behavioural traits across ontogenetic stages in a sexually-size dimorphic spider

Selection acts differently on females and males due to differences in potential reproductive rates, driving the evolution of sex differences in traits, including growth and behaviour. Additionally, selection pressures vary during an individual's ontogeny, with growth being crucial in early developmental stages and reproduction during adulthood, leading to age- and sex-specific behavioural strategies. In this study, we investigated a sexually-size dimorphic spider, the raft spider (Dolomedes fimbriatus), where females are substantially larger than males. We repeatedly observed spiders from juvenile to adult stages, examining boldness, voracity towards prey, and probability to attack. Our findings revealed that females exhibited greater boldness, voracity, and probability to back-attack the simulated attacker compared to males. Notably, the observed behaviours changed during ontogeny, with sex differences in the magnitudes and directions of change, indicating distinct life history strategies between sexes. Moreover, we detected positive associations between body mass or age and behavioural traits, supporting a proposed positive feedback loop between assets and behaviour. While mass and age were not significant confounding predictors in the analyses of sex differences in behaviour, some collinearity was present between sex, mass, and age, so that their effects on behavioural differences between sexes cannot be conclusively disentangled. Repeatability of behaviours was low but significant for boldness and probability to attack, with similar estimates between sexes. These results underscore the importance of considering sex-specific life history strategies in behavioural trait studies.

Identification of quantitative trait loci and associated candidate genes for pregnancy success in Angus – Brahman crossbred heifers

Development of genomic tools to identify females with high genetic merit for reproductive function could increase the profitability and sustainability of beef production. Here, genome-wide association studies (GWAS) were performed on pregnancy outcome traits from a population of Angus – Brahman crossbred heifers. Furthermore, a validation GWAS was performed using data from another location. Heifers were genotyped with the Bovine GGP F250 array that contains ~250,000 SNPs. In the discovery population, heifers were bred in winter breeding seasons involving a single round of timed artificial insemination (AI) followed by natural mating for three months. Three phenotypes were analyzed: pregnancy outcome to first-service AI (PAI; n = 1481), pregnancy status at the end of the breeding season (PEBS; n = 1725), and pregnancy score (Pregscore where 1 = pregnant to first-service AI, 2 = pregnant to bull, 3 = not pregnant; n =1481). The heritability for PAI was estimated as 0.149. One large quantitative trait locus (QTL) that explained ~3% of the genetic variation for PAI was found on BTA7, in a region containing a cluster of γ-protocadherin genes and SLC25A2. Other QTLs explaining between 0.5-1% of the genetic variation were found on BTA12 and 25. The heritability of PEBS was estimated at 0.122. A large QTL on BTA7 was synonymous with the QTL for PAI, with minor QTL located on BTA5, 9, 10, 11, 19, and 20. Estimated heritability for Pregscore was 0.189. There was a large QTL on BTA7 synonymous with the other two traits as well as smaller QTLs on BTA1, 10, 15, 18, 19, and 20. The validation population for pregnancy status at the end of the breeding season were Angus-Brahman crossbred heifers bred by natural mating. In concordance with the discovery population, the large QTL on BTA7 and QTL on BTA10, 12 and 18 were identified. In summary, QTL and candidate SNPs associated with pregnancy outcomes in beef heifers were identified, including a large QTL associated with a group of protocadherin genes. Confirmation of these associations with larger populations could lead to the development of genomic estimates of reproductive function in beef cattle.

A trait-based approach to assess niche overlap and functional distinctiveness between non-indigenous and native species

Our understanding of the community assembly processes acting on non-indigenous species (NIS), as well as the relationship with native species is limited, especially in marine ecosystems. To overcome this knowledge gap we here develop a trait-based approach based on the functional distinctiveness metric to assess niche overlap between NIS and native species, using high-resolution data on benthic invertebrate communities in the Baltic Sea. Our results show that NIS retain a certain degree of similarity with native species, but display one or a few singular unique traits (e.g., bioturbation ability). Furthermore, we demonstrate that community assembly processes, including both environmental filtering and limiting similarity affect NIS establishment, but that their effects may be highly context dependent, as illustrated by pronounced spatial patterns in distinctiveness. Finally, our trait-based approach provides a generic framework applicable to other areas and organisms, to better understand and address biological invasions.

Anisogamy does not always promote the evolution of mating competition traits in males

Anisogamy has evolved in most sexually reproducing multicellular organisms allowing the definition of the male and female sexes, producing small and large gametes. Anisogamy, as the initial sexual dimorphism, is a good starting point to understand the evolution of further sexual dimorphisms. For instance, it is generally accepted that anisogamy sets the stage for more intense mating competition in males than in females. We argue that this idea stems from a restrictive assumption on the conditions under which anisogamy evolved in the first place: the absence of sperm limitation (assuming that all female gametes are fertilized). Here, we relax this assumption and present a model that considers the coevolution of gamete size with a mating competition trait, starting in a population without dimorphism. We vary gamete density to produce different scenarios of gamete limitation. We show that, while at high gamete density the evolution of anisogamy always results in male investment in competition, gamete limitation at intermediate gamete densities allows for either females or males to invest more into mating competition. Our results thus suggest that anisogamy does not always promote mating competition among males. The conditions under which anisogamy evolves matter, as well as the competition trait.

opencc-by-4.0Sep 2023View details →

zenodo36/100

Functional traits of the ichthyofauna from Terminos Lagoon, Campeche, Mexico

The dataset provides access to an Excel file (.xlsx) with a list of 128 fish species (rows), and a list of 23 bio-ecological traits grouped into 5 categories (columns). The characterization of the bio-ecological traits by species was done with information from primary literature, free access internet data repositories, and databases of previous institutional projects. In this way, a matrix of bio-ecological attributes of the fish community was assembled. Aspects related with the study area, the sampling design, the collection methodology, the species inventory, and the taxonomic composition of the ichthyofauna are described in Paz-Ríos et al. (2021). Link to this article: <a href="https://doi.org/10.3897/BDJ.9.e65317">https://doi.org/10.3897/BDJ.9.e65317</a>

Larval and adult traits coevolve in response to asymmetric coastal currents to shape marine dispersal kernels

Dispersal emerges as an outcome of organismal traits and external forcings. However, it remains unclear how the emergent dispersal kernel evolves as a by-product of selection on the underlying traits. This question is particularly compelling in coastal marine systems where dispersal is tied to development and reproduction, and where directional currents bias larval dispersal downstream causing selection for retention. We modelled the dynamics of a metapopulation along a finite coastline using an integral projection model and adaptive dynamics to understand how asymmetric coastal currents influence the evolution of larval (pelagic larval duration) and adult (spawning frequency) life history traits, which indirectly shape the evolution of marine dispersal kernels. Selection induced by alongshore currents favors the release of larvae over multiple time periods, allowing long pelagic larval durations and long-distance dispersal to be maintained in marine life cycles in situations where they were previously predicted to be selected against. Two evolutionary stable strategies emerged: one with a long pelagic larval duration and many spawning events resulting in a dispersal kernel with a larger mean and variance, and another with a short pelagic larval duration and few spawning events resulting in a dispersal kernel with a smaller mean and variance. Our theory shows how coastal ocean flows are important agents of selection that can generate multiple, often co-occurring, evolutionary outcomes for marine life history traits that affect dispersal.

Data from: Genomic and transcriptomic analyses reveal polygenic architecture for ecologically-important functional traits in aspen (Populus tremuloides Michx.)

Intraspecific genetic variation in foundation species such as aspen (Populus tremuloides Michx.) shapes their impact on forest structure and function. Identifying genes underlying ecologically important traits is key to understanding that impact. Previous studies, using single-locus genome-wide association (GWA) analyses to identify candidate genes, have identified fewer genes than anticipated for highly heritable quantitative traits. Mounting evidence suggests that polygenic control of quantitative traits is largely responsible for this "missing heritability" phenomenon. Our research characterized the genetic architecture of 30 ecologically important traits using a common garden of aspen through genomic and transcriptomic analyses. A multilocus association model revealed that most traits displayed a highly polygenic architecture, with most variation explained by loci with small effects (likely below the detection levels of single-locus GWA methods). Consistent with a polygenic architecture, our single-locus GWA analyses found only 38 significant SNPs in 22 genes across 15 traits. Next, we used differential expression analysis on a subset of aspen genets with divergent concentrations of salicinoid phenolic glycosides (key defense traits). This complementary method to traditional GWA discovered 1,243 differentially expressed genes for a polygenic trait. Soft clustering analysis revealed three gene clusters (241 candidate genes) involved in secondary metabolite biosynthesis and regulation. Our work reveals that ecologically important traits governing higher-order community- and ecosystem-level attributes of a foundation forest tree species have complex underlying genetic structures and will require methods beyond traditional GWA analyses to unravel.

Functional traits and drought strategy predict leaf thermal tolerance

Heat stress imposes an important physiological constraint on native plant species – one that will only worsen with human-caused climate change. Indeed, rising temperatures have already contributed to large-scale plant mortality events across the globe. These impacts may be especially severe in cities, where the urban heat island effect amplifies climate warming. Understanding how plant species will respond physiologically to rising temperatures and how these responses differ among plant functional groups is critical for predicting future biodiversity scenarios and making informed land management decisions. In this study, we evaluated the effects of elevated temperatures on a functionally and taxonomically diverse group of woody native plant species in a restored urban nature preserve in southern California using measurements of chlorophyll fluorescence as an indicator of leaf thermotolerance. Our aim was to determine if species' traits and drought strategies could serve as useful predictors of thermotolerance. We found that leaf thermotolerance differed among species with contrasting drought strategies, and several leaf-level functional traits were significant predictors of thermotolerance thresholds. Drought deciduous species with high specific leaf area, high rates of transpiration, and low water-use efficiency were the most susceptible to heat damage, while evergreen species with sclerophyllous leaves, high relative water content, and high water-use efficiency maintained photosynthetic function at higher temperatures. While these native shrubs and trees are physiologically equipped to withstand relatively high temperatures in this Mediterranean-type climate, hotter conditions imposed by climate change and urbanization may exceed the tolerance thresholds of many species. We show that leaf functional traits and plant drought strategies may serve as useful indicators of species' vulnerabilities to climate change, and this information can be used to guide restoration and conservation in a warmer world.

Shifts in wood anatomical traits after a major hurricane

Trait variation across individuals and species influences the resistance and resilience of ecosystems to disturbance, and the ability of individuals to capitalize on post-disturbance conditions. In trees, the anatomical structure of the xylem directly affects plant function and, consequently, it is a valuable lens through which to understand resistance and resilience to disturbance. To determine how hurricanes affect the wood anatomy of tropical trees, we characterized a set of anatomical traits in wood produced before and after a major hurricane for 65 individuals of ten Puerto Rican tree species. We quantified variation at different scales and determined trait shifts between the pre- and post-hurricane periods. We also assessed correlations between traits and growth rates. While the majority of anatomical trait variation occurred among species, we also observed substantial variation within species and individuals. Within individuals, we found significant shifts for some traits that generally reflected increased hydraulic conductivity in the post-hurricane period. We found weak evidence for an association between individual xylem anatomical traits and diameter growth rates. Ultimately, within-individual variation of xylem anatomical traits observed in our study could be related to post-hurricane recovery and overall growth (e.g., canopy filling). Other factors, however, likely decouple a relationship between xylem anatomy and diameter growth. While adjustments of wood anatomy may enable individual trees to capitalize on favorable post-disturbance conditions, these may also influence their future responses or vulnerability to subsequent disturbances.

Artificial light at night (ALAN) decreases plant diversity and performance in experimental grassland communities – Data on species biomass and traits

Artificial light at night (ALAN) affects many areas of the world and is increasing globally. To date, there has been limited and inconsistent evidence regarding the consequences of ALAN on plant communities as well as the fitness of their constituent species. ALAN could be beneficial for plants as they need light as an energy source, but they also need darkness for regeneration and growth. We created model communities composed of 16 plant species sown, exposed to a gradient of ALAN ranging from 'moonlight only' to conditions like situations typically found directly underneath a streetlamp. We measured plant community composition and its production (biomass), as well as functional traits of three plant species from different functional groups (grasses, herbs, legumes) in two separate harvests. We found that biomass was reduced by 33% in the highest ALAN treatment compared to the control, Shannon diversity decreased by 43% and Evenness by 34% in the first harvest. Some species failed to establish in the second harvest. Specific leaf area, leaf dry matter content and leaf hairiness responded to ALAN. These responses suggest that plant communities will be sensitive to increasing ALAN, and they flag a need for plant conservation activities that consider impending ALAN scenarios.

Functional trait measurements of wheat

Crop domestication has led to the development of distinct trait syndromes, a series of constrained plant trait trade-offs to maximize yield in high-input agricultural environments, and potentially constrained trait plasticity. Yet, with the ongoing transition to organic and diversified agroecosystems, which create more heterogeneous nutrient availability, this constrained plasticity, especially in root functional traits, may be undesirable for nutrient acquisition. Such agricultural systems require a nuanced understanding of the soil-crop continuum under organic amendments and with intercropping, and the role crop genetic resources play in governing nutrient management and design. In this study, we use a functional traits lens to determine if crops with a range of domestication histories express different functional trait plasticity and how this expression changes with soil amendments and intercropping. We utilize a common garden experiment including five wheat (Triticum aestivum) varietals with a range of domestication histories planted in a factorial combination with amendment type (organic and inorganic) and cropping design (monoculture or intercropped with soybean). We use bivariate, multivariate and trait space analyses to quantify trait variation and plasticity in five leaf and five root functional traits. Almost all leaf and root traits varied among varieties. Yet, amendment type was nearly inconsequential for explaining trait expression across varieties. However, intercropping was linked to significant differences in root acquisitive strategies, regardless of the varietals' distinct history. Our findings show substantial leaf and root trait plasticity, with roots expressing greater trait space occupation with domestication, but also the strong role of management in crop trait expression. We underscore the utility of a functional trait-based approach to understand plant-soil dynamics with organic amendments, as well as the role of crop genetic histories in the successful transition to low-input and diversified agroecosystems.

Microbial traits dictate soil neromass accumulation coefficient: A global synthesis

The accumulation of microbial necromass carbon has drawn mounting attention due to the slow decomposition. However, it remains unclear what determines the microbial necromass carbon accumulation via reiterated community turnover on large spatial scales. This study aimed to explore the characteristics of soil necromass carbon accumulation in terrestrial ecosystems. A dataset was compiled with 993 observations on the coefficient of microbial carbon accumulation in the equilibrium from 82 peer-reviewed papers. The linear mixed-effect models and structural equation models were used to ascertain the controlling factors of NAC on a global scale. The average NAC was higher in croplands (28.2) and forests (26.8) than that in grasslands (21.1). Although the edaphic factors seemingly affect the NAC whereby the NAC lowered in soils with high levels of pH and clay content on a global scale, the biotic factors, particularly for the living microorganism abundance and microbial biomass nitrogen content, were the pivotal drivers of NAC that accounted for approximately 42.5% of the geographic variances in NAC. More organic carbon was likely to be preserved in soil with a higher NAC regardless of ecosystem types. Novel findings on the overriding controls from the living microorganism abundance and microbial biomass nitrogen in driving NAC raise an urgent need for viable strategies in manipulating microbial characteristics for carbon sequestrations.

Data from: Sexually attractive traits predict predation-threat sensitivity of male alternative mating tactics

Although visual sexual signals, such as ornamental colors and courtship displays, and large body size in males are attractive to females in numerous species, they may also inadvertently attract the attention of eavesdropping predators and thus may be costly in terms of increasing individual risk of mortality to predation. Theoretically, more color-ornamented and larger males should be more predation threat sensitive and suppress their sexual signaling and(or) mating effort relatively more than their less color-ornamented and smaller counterparts when under predation hazard. Here, we experimentally tested this hypothesis by quantifying concurrently the rates of alternative mating tactics (courtship displays, sneak mating attempts) expressed by male Trinidadian guppies (Poecilia reticulata) varying in color ornamentation and body size under a staged immediate threat of predation. Males suppressed their overall mating effort in response to the perceived predation threat, decreasing the frequency of their (presumably more conspicuous) courtship displays significantly more on average than the frequency of their sneak mating behavior. Statistically controlling for body length, more color-ornamented males were more threat-sensitive in their courtship displays, but not sneak mating attempts, under predation hazard than drabber males. Controlling for body coloration, larger males exhibited lower courtship and sneak mating efforts than smaller males in both predation treatments, but body length only influenced threat sensitivity in sneak mating behavior. These results are consistent with both the threat-sensitive hypothesis and asset protection principle and highlight the phenotype-dependency and adaptive plasticity of alternative mating tactics in male guppies under varying predation risk.

Assessing the evolutionary lability of insulin signaling in the regulation of nutritional plasticity across traits and species of horned dung beetles

Nutrition-dependent growth of sexual traits is a major contributor to phenotypic diversity and a large body of research documents insulin signaling as a major regulator of nutritional plasticity. However, findings across studies raise the possibility that the role of individual components within the insulin signaling pathway diverge in function among traits and taxa. Here, we use RNAi-mediated transcript depletion in the gazelle dung beetle to investigate the functions of forkhead box O (Foxo) and two paralogs of the insulin receptor (InR1 and InR2) in shaping nutritional plasticity in polyphenic male head horns, exaggerated fore legs, and weakly nutrition-responsive genitalia. Our functional genetic manipulations led to three main findings: FoxoRNAi reduced the length of exaggerated head horns in large males, while neither InR1 nor InR2 knock-downs resulted in measurable horn phenotypes. These results are similar to those documented previously for another horned dung beetle species (Onthophagus taurus), but in stark contrast to findings in rhinoceros beetles. Secondly, knockdown of Foxo, InR1, and InR2 led to an increase in the intercept or slope of the scaling relationship of genitalia size. These results are in contrast even to results documented previously for O. taurus. Lastly, while FoxoRNAi reduces male forelegs in D. gazella and O. taurus, the effects of InR1 and InR2 knockdowns diverged across dung beetle species. Taken together, our results add to the growing body of literature indicating that despite insulin signaling's conserved role as a regulator of nutritional plasticity, the functions of its components may diversify among traits and species.

opencc-zeroDec 2022View details →

Sexually concordant selection on floral traits despite greater opportunity for selection through male fitness

Pollinators are important drivers of floral trait evolution, yet plant populations are not always perfectly adapted to their pollinators. Such apparent maladaptation may result from conflicting selection through male and female sexual functions in hermaphrodites. We studied sex-specific mating patterns and phenotypic selection on floral traits in Aconitum gymnandrum. After genotyping 1786 offspring, we partitioned individual fitness into sex-specific selfed and outcrossed components and estimated phenotypic selection acting through each. Relative fitness increased with increasing mate number, and more so for male function. This led to greater opportunity for selection through outcrossed male fitness, though patterns of phenotypic selection on floral traits tended to be similar, and with better support for selection through female rather than male fitness components. We detected directional selection through one or more fitness components for larger flower number, larger flowers, and more negative nectar gradients within inflorescences. Our results are consistent with Bateman's principles for sex-specific mating patterns and illustrate that, despite the expected difference in opportunity for selection, patterns of variation in selection across traits can be rather similar for the male and female sexual functions. These results shed new light on the effect of sexual selection on the evolution of floral traits.

Effects of large mammal exclusion on seedling communities depend on plant species traits and landscape protection in human-modified Costa Rican forests

<ol> <li>Large terrestrial herbivorous mammals (LTH-mammals) influence plant community structure by affecting seedling establishment in mature tropical forests. Many of these LTH-mammals frequent secondary forests, but their effects on seedling establishment in them are understudied, hindering our understanding of how LTH-mammals influence forest regeneration in human-modified landscapes.</li> <li>We tested the hypothesis that the strength of LTH-mammals' effects on seedling establishment depends on landscape protection, forest successional stage, and plant species' traits using a manipulative field experiment in six 1-ha sites with varying successional age and landscape protection. In each site, we established forty seedling plot-pairs, with one plot excluding LTH-mammals and one not, and monitored seedlings of 116 woody species for 26 months.</li> <li>We found significant effects of LTH-mammal exclusion on seedling survival contingent upon the protection of forests at the landscape level and forest stage. After 26 months, survival differences between LTH-mammal exclusion and non-exclusion treatments were greater in protected than unprotected landscapes. Additionally, plant species' traits were related to the LTH-mammals' differential effects, as LTH-mammals reduced the survival of seedlings of larger-seeded species the most. Overall, LTH-mammals' effects translated into significant shifts in community composition as seedling communities inside and outside the exclosures diverged. Moreover, lower density and higher species diversity were found as early as 12 and 18 months outside than inside exclosures.</li> <li> Synthesis and applications. Insight into the interactions between LTH-mammals and seedling communities in forest regeneration can be instrumental in planning effective restoration efforts. We highlight the importance of landscape protection in seedling survival and the role of LTH-mammals in promoting seedling diversity in mature forests but also in secondary successional forests. The findings suggest that conservation efforts and possibly trophic rewilding can be important approaches for preserving diversity and influencing the trajectory of secondary tropical forest succession. However, we also caution that an overabundance of LTH-mammals may adversely impact the pace of forest succession due to their preference for large-seeded species. Therefore, a comprehensive wildlife management plan is indispensable. Additionally, longer-term studies on LTH-mammals are necessary to understand the effects of temporal fluctuations that are undetected in short-term studies.</li> </ol>

opencc-by-sa-4.0Oct 2023View details →

zenodo36/100

Data from: Leaf trait variation within individuals mediates the relationship between tree species richness and productivity

This dataset contains tree biometry data and leaf trait data of the Kreinitz Tree Diversity Experiment. In winter 2013/14 and winter 2016/17, height and basal area were measured for all 2880 individuals of the Kreinitz experiment. Tree biometry data is available in the file Data_Kreinitz_Tree.xlsx. In summer 2017, leaf traits for 283 selected trees were measured via near-infrared spectroscopy. For each tree, samples were taken from approximately 3 levels in the trees' crown (total 843 levels). At each level, approximately 4 leaves were harvested (total 3656 leaves) and scanned in triplicates (total 10986 scans). Sampled leaves were scanned on the day of harvest. Leaf trait data is available in the file Data_Kreinitz_Leaf.xlsx.

Vertically inherited microbiota and environment-modifying behaviors indirectly shape the exaggeration of secondary sexual traits in the gazelle dung beetle

Many organisms actively manipulate the environment in ways that have the potential to feed back on their own development, a process referred to as developmental niche construction. Yet, the role that constructed biotic and abiotic environments play in shaping phenotypic variation and its evolution is insufficiently understood. Here, we assess whether environmental modifications made by developing dung beetles impact the environment-sensitive expression of secondary sexual traits. Larval gazelle dung beetles both physically modify their ontogenetic environment and structure their biotic interactions through the vertical inheritance of microbial symbionts. By experimentally eliminating i) physical environmental modifications, and ii) the vertical inheritance of microbes, we assess the degree to which (sym)biotic and physical environmental modifications shape the exaggeration of several traits varying in their degree and direction of sexual dimorphism. We expected the experimental reduction of a larva's ability to shape its environment to affect trait size and scaling, especially for traits that are sexually dimorphic and environmentally plastic. We find that compromised developmental niche construction indeed shapes sexual dimorphism in overall body size and the absolute sizes of male-limited exaggerated head horns, the strongly sexually dimorphic fore tibia length and width, as well as the weakly dimorphic elytron length and width. This suggests that ontogenetic environmental modifications affect sex-specific phenotypic variation in functional traits. However, most of these effects can be attributed to nutrition-dependent plasticity in size and non-isometric trait scaling, rather than body-size-independent effects on the developmental regulation of trait size. Our findings suggest that the reciprocal relationship between developing organisms, their symbionts, and their environment can have considerable impacts on sexual dimorphism and functional morphology.

Experimental and theoretical support for costs of plasticity and phenotype in a nematode cannibalistic trait

Developmental plasticity is the ability of a genotype to express multiple phenotypes under different environmental conditions and has been shown to facilitate the evolution of novel traits. However, while the associated cost of plasticity, i.e., the loss in fitness due to the ability to express plasticity in response to environmental change, and the cost of phenotype, i.e., the loss of fitness due to expressing a fixed phenotype across environments, have been theoretically predicted, empirically such costs remain poorly documented and little understood. Here, we use a plasticity model system, hermaphroditic nematode Pristionchus pacificus, to experimentally measure these costs in wild isolates under controlled laboratory conditions. P. pacificus can develop either a bacterial feeding or predatory mouth morph in response to different external stimuli, with natural variation of mouth-morph ratios between strains. We first demonstrated the cost of phenotype by analyzing fecundity and developmental speed in relation to mouth morphs across the P. pacificus phylogenetic tree. Then, we exposed P. pacificus strains to two distinct microbial diets that induce strain-specific mouth-form ratios. Our results indicate that the plastic strain does shoulder a cost of plasticity, i.e., the diet-induced predatory mouth morph is associated with reduced fecundity and slower developmental speed. In contrast, the non-plastic strain suffers from the cost of phenotype since its phenotype does not change to match the unfavorable bacterial diet but shows increased fitness and higher developmental speed on the favorable diet. Furthermore, using a stage-structured population model based on empirically derived life history parameters, we show how population structure can alleviate the cost of plasticity in P. pacificus. The results of the model illustrate the extent to which the costs associated with plasticity and its effect on competition depend on ecological factors. This study provides support for costs of plasticity and phenotype based on empirical and modeling approaches.