Find research datasets worth reusing

Data from: Heritability, evolvability, phenotypic plasticity and temporal variation in sperm-competition success of Drosophila melanogaster

Sperm-competition success (SCS) is seen as centrally important for evolutionary change: superior fathers sire superior sons and thereby inherit the traits that make them superior. Additional hypotheses, that phenotypic plasticity in SCS and sperm ageing explain variation in paternity, are less considered. Even though various alleles have individually been shown to be correlated with variation in SCS, few studies have addressed the heritability, or evolvability, of overall SCS. Those studies that have, found low or no heritability and have not examined evolvability. They have further not excluded phenotypic plasticity, and temporal effects on SCS, despite their known dramatic effects on sperm function. In Drosophila melanogaster, we found that both standard components of sperm competition, sperm defence and sperm offence, showed non-significant or insignificant heritability across several offspring cohorts. Instead, our analysis revealed, for the first time, the existence of phenotypic plasticity in SCS across an extreme environment (5% CO2), and an influence of sperm ageing. Evolvability of SCS was substantial for sperm defence but virtually absent for sperm offence. Our results suggest that the paradigm of explaining evolution by sperm competition is more complex and will benefit from further experimental work on the heritability or evolvability of SCS, measuring phenotypic plasticity, and separating the effects of sperm competition and sperm ageing.

Data from: Environmental heterogeneity does not affect levels of phenotypic plasticity in natural populations of three Drosophila species

Adaptation of natural populations to variable environmental conditions may occur by changes in trait means and/or in the levels of plasticity. Theory predicts that environmental heterogeneity favors plasticity of adaptive traits. Here we investigated the performance in several traits of three sympatric Drosophila species freshly collected in two environments that differ in the heterogeneity of environmental conditions. Differences in trait means within species were found in several traits, indicating that populations differed in their evolutionary response to the environmental conditions of their origin. Different species showed distinct adaptation with a very different role of plasticity across species for coping with environmental changes. However, geographically distinct populations of the same species generally displayed the same levels of plasticity as induced by fluctuating thermal regimes. This indicates a weak and trait-specific effect of environmental heterogeneity on plasticity. Furthermore, similar levels of plasticity were found in a laboratory-adapted population of Drosophila melanogaster with a common geographic origin but adapted to the laboratory conditions for more than 100 generations. Thus, this study does not confirm theoretical predictions on the degree of adaptive plasticity among populations in relation to environmental heterogeneity but shows a very distinct role of species-specific plasticity.

Data from: Predation risk determines pigmentation phenotype in nuthatches by melanin-related gene expression effects

Pigments determine the appearance of organisms. However, pigment production can be associated to physiological constraints as in the case of pheomelanin, the sulphurated form of melanin whose synthesis in melanocytes consumes cysteine and consequently reduces the availability of glutathione (GSH) to exert antioxidant protection. Pheomelanogenesis may thus increase the susceptibility to suffer chronic oxidative stress. I investigated the possibility that environmental lability in the expression of genes regulating pheomelanogenesis protects from oxidative stress, a situation in which GSH is most required. By broadcasting adult alarm calls, I manipulated the perception of predation risk, a natural source of oxidative stress, in free-living Eurasian nuthatch Sitta europaea nestlings developing pheomelanin-pigmented flank feathers. The manipulation affected the consumption of GSH that resulted from the expression of two genes (Slc7a11 and Slc45a2) influencing cysteine/GSH availability in cells, as these genes were downregulated in the feather melanocytes of the nestlings with lowest intracellular antioxidant capacity (i.e., lowest GSH levels). Systemic oxidative damage increased with Slc7a11 expression in feather melanocytes, suggesting that the observed downregulation was physiologically advantageous. The nestlings exposed to an increased perception of predation risk developed flank feathers of reduced color intensity. These results indicate that perceived predation risk can determine the pigmentation phenotype by (probably epigenetic) effects on gene expression that protect from physiological constraints imposed by pheomelanin production.

opencc-zeroDec 2014View details →

Data from: Insect mating signal and mate preference phenotypes covary among host plant genotypes

Sexual selection acting on small initial differences in mating signals and mate preferences can enhance signal-preference co-divergence and reproductive isolation during speciation. However, the origin of initial differences in sexual traits remains unclear. We asked whether biotic environments, a source of variation in sexual traits, may provide a general solution to this problem. Specifically, we asked whether genetic variation in biotic environments provided by host plants can result in signal-preference phenotypic covariance in a host-specific, plant-feeding insect. We used a member of the Enchenopa binotata species complex of treehoppers (Hemiptera: Membracidae) to assess patterns of variation in male mating signals and female mate preferences induced by genetic variation in host plants. We employed a novel implementation of a quantitative genetics method, rearing field-collected treehoppers on a sample of naturally-occurring replicated host plant clone lines. We found remarkably high signal-preference covariance among host plant genotypes. Thus, genetic variation in biotic environments influences the sexual phenotypes of organisms living on those environment in a way that promotes assortative mating among environments. This consequence arises from conditions likely to be common in nature (phenotypic plasticity and variation in biotic environments). It therefore offers a general answer to how divergent sexual selection may begin.

Data from: microCT-based phenomics in the zebrafish skeleton reveals virtues of deep phenotyping in a distributed organ system

Phenomics, which ideally involves in-depth phenotyping at the whole-organism scale, may enhance our functional understanding of genetic variation. Here, we demonstrate methods to profile hundreds of phenotypic measures comprised of morphological and densitometric traits at a large number of sites within the axial skeleton of adult zebrafish. We show the potential for vertebral patterns to confer heightened sensitivity, with similar specificity, in discriminating mutant populations compared to analyzing individual vertebrae in isolation. We identify phenotypes associated with human brittle bone disease and thyroid stimulating hormone receptor hyperactivity. Finally, we develop allometric models and show their potential to aid in the discrimination of mutant phenotypes masked by alterations in growth. Our studies demonstrate virtues of deep phenotyping in a spatially distributed organ system. Analyzing phenotypic patterns may increase productivity in genetic screens, and facilitate the study of genetic variants associated with smaller effect sizes, such as those that underlie complex diseases.

Data from: Male phenotypic diversity experienced during ontogeny mediates female mate choice in guppies

Early social experience can be important in shaping female mate choice. Previous work has shown that females adjust their decisions based on the distribution of male sexual trait values encountered during development. However, other phenotypic features could be important in the formation of mate preferences if, for example, they provide additional information about the males available. Here, we examined how the level of overall phenotypic variance (independent of trait values) experienced during ontogeny, mediated female choice in guppies, Poecilia reticulata. Developing females were reared with males either all different in colouration or all similar in colouration or with adult females representing high variance, low variance and no experience of male variance respectively. We found that females were more sexually responsive when reared with females only than in either of the male treatments. When reared with males, responsiveness was greater in the low-variance compared to the high variance treatment. Moreover, females had stronger sexual preferences following rearing in the high variance compared to the low variance condition. In turn, males switched mating tactics, increasing the rate of coerced copulation attempts when facing choosier females, possibly to balance the loss in mating opportunities. Taken together, these results demonstrate the adaptive plasticity of female mating decisions and the dynamic selection pressures they might impose on the evolution of male sexual traits, potentially contributing to the maintenance of the extreme polymorphism found in male colour patterns.

Data from: Early postnatal exposure to airborne fine particulate matter induces autism-like phenotypes in male rats

Epidemiological studies have revealed that ambient fine particulate matter (PM2.5) exposure is closely associated with autism spectrum disorder (ASD). However, there is a relative paucity of laboratory data to support this epidemic finding. In order to assess the relationship between PM2.5 exposure and ASD, neonatal male Sprague-Dawley (SD) rats were chosen and exposed to PM2.5 (2 or 20 mg/kg body weight, once a day) by intranasal instillation from postnatal day (PND) 8 to 22. It was found that when exposed to PM2.5 in the early neonatal period for two weeks, both groups of the exposure rats manifested typical behavioral features of autism, including communication deficits, poor social interaction and novelty avoidance. And, we further found, among five ASD candidate genes we chose, both the mRNA level and protein expression of SH3 and multiple ankyrin repeat domains 3 (Shank3) decreased significantly in the rat hippocampus after high dose of PM2.5 exposure. Moreover, results showed that PM2.5-exposure significantly increased the levels of pro-inflammatory cytokines, IL-1β, IL-6, and TNF-α in the hippocampus and prefrontal cortex. The expression of Glial fibrillary acidic protein (GFAP) and ionized binding calcium adapter molecule (IBA1), markers of astrocytes and microglial cell activation, respectively, also increased in the exposed animals. Our work provides new data on the link between postnatal exposure to ambient PM2.5 and the onset of ASD-like symptoms in human beings, and the increased inflammatory response and abnormalities in Shank3 expression in the brain may contribute to the mechanisms of PM2.5 exposure induced ASD.

opencc-zeroDec 2014View details →

Data from: Using the Phenoscape Knowledgebase to relate genetic perturbations to phenotypic evolution

The abundance of phenotypic diversity among species can enrich our knowledge of development and genetics beyond the limits of variation that can be observed in model organisms. The Phenoscape Knowledgebase (KB) is designed to enable exploration and discovery of phenotypic variation among species. Because phenotypes in the KB are annotated using standard ontologies, evolutionary phenotypes can be compared with phenotypes from genetic perturbations in model organisms. To illustrate the power of this approach, we review the use of the KB to find taxa showing evolutionary variation similar to that of a query gene. Matches are made between the full set of phenotypes described for a gene and an evolutionary profile, the latter of which is defined as the set of phenotypes that are variable among the daughters of any node on the taxonomic tree. Phenoscape's semantic similarity interface allows the user to assess the statistical significance of each match and flags matches that may only result from differences in annotation coverage between genetic and evolutionary studies. Tools such as this will help meet the challenge of relating the growing volume of genetic knowledge in model organisms to the diversity of phenotypes in nature. The Phenoscape KB is available at http://kb.phenoscape.org.

opencc-zeroDec 2008View details →

Data from: The genetics of phenotypic plasticity in plant defense: trichome production in Mimulus guttatus

Insect herbivory is a major driving force of plant evolution. Phenotypic plasticity and developmental variation provide a means for plants to cope with variable herbivory. We characterized the genetics of developmental variation and phenotypic plasticity in trichome density, a putative defensive trait of Mimulus guttatus (yellow monkeyflower). Our results are evaluated in relation to the optimal defense theory, which provides testable predictions for plastic and developmental patterns in defense traits. We found that both developmental stage and simulated insect damage affected trichome production, but in different ways. Plants were more likely to produce at least some trichomes on later leaves than on earlier leaves, regardless of damage. Damage did not affect the average probability of producing trichomes, but it did increase the density of hairs on trichome‐positive plants. We mapped trichome quantitative trait loci (QTL) by selectively genotyping a large panel of recombinant inbred lines derived from two highly divergent populations. Several highly pleiotropic QTL influenced multiple aspects of the trichome phenotype (constitutive, developmental, and/or plastic responses). Only one of the QTL influenced trichome induction following damage. In a result that is consistent with a central prediction of optimal defense theory, the high allele at this location was from the ancestral population with low constitutive trichome production.

Data from: Phenotypic biomarkers of climatic impacts on declining insect populations: a key role for decadal drought, thermal buffering and amplification effects and host plant dynamics

1. Widespread population declines have been reported for diverse Mediterranean butterflies over the last three decades, and have been significantly associated to increased global change impacts. The specific landscape and climatic drivers of these declines remain uncertain for most declining species. 2. Here we analyse whether plastic phenotypic traits of a model butterfly species (Pieris napi) perform as reliable biomarkers of vulnerability to extreme temperature impacts in natural populations, showing contrasting trends in thermally exposed and thermally buffered populations. 3. We also examine whether improved descriptions of thermal exposure of insect populations can be achieved by combining multiple information sources (i.e. integrating measurements of habitat thermal buffering, habitat thermal amplification, host plant transpiration, and experimental assessments of thermal death time (TDT), thermal avoidance behaviour (TAB) and thermally induced trait plasticity). These integrative analyses are conducted in two demographically declining and two non-declining populations of P. napi. 4. The results show that plastic phenotypic traits (butterfly body mass and wing size) are reliable biomarkers of population vulnerability to extreme thermal conditions. Butterfly wing size is strongly reduced only in thermally exposed populations during summer drought periods. Lab rearing of these populations documented reduced wing size due to significant negative effects of increased temperatures affecting larval growth. We conclude that these thermal biomarkers are indicative of the population vulnerability to increasing global warming impacts, showing contrasting trends in thermally exposed and buffered populations. 5. Thermal effects in host plant microsites significantly differ between populations, with stressful thermal conditions only effectively ameliorated in mid-elevation populations. In lowland populations we observe a six-fold reduction in vegetation thermal buffering effects, and larval growth occurs in these populations at significantly higher temperatures. Lowland populations show reduced host plant quality (C/N ratio), reduced leaf transpiration rates and complete aboveground plant senescence during the peak of summer drought. Amplified host plant temperatures are observed in open microsites, reaching thermal thresholds that can affect larval survival. 6. Overall, our results suggest that butterfly population vulnerability to long-term drought periods is associated to multiple co-occurring and interrelated ecological factors, including limited vegetation thermal buffering effects at lowland sites, significant drought impacts on host plant transpiration and amplified leaf surface temperature, as well as reduced leaf quality linked to the seasonal advance of plant phenology. Our results also identify multi-annual summer droughts affecting larval growing periods as a key driver of the recently reported butterfly population declines in the Mediterranean biome.

Data from: Many-to-many mapping of phenotype to performance: an extension of the F-matrix for studying functional complexity

Performance capacity influences ecology, behavior and fitness, and is determined by the underlying phenotype. The phenotype-performance relationship can influence the evolutionary trajectory of an organism. Several types of phenotype-performance relationships have been described, including one-to-one relationships between a single phenotypic trait and performance measure, trade-offs and facilitations between a phenotypic trait and multiple performance measures, and redundancies between multiple phenotypic traits and a single performance measure. The F-matrix is an intraspecific matrix of measures of statistical association between phenotype and performance that is used to quantify these relationships. We extend the F-matrix in two ways. First, we use the F-matrix to describe how the different phenotype-performance relationships occur simultaneously and interact in functional systems, a phenomenon we call many-to-many mapping. Second, we develop methods to compare F-matrices among species and compare phenotype-performance relationships at microevolutionary and macroevolutionary levels. We demonstrate the expanded F-matrix approach with a dataset of eight phrynosomatine lizard species, including six phenotypic traits and two measures of locomotor performance. Our results suggest that all types of relationships occur in this system and that phenotypic traits involved in trade-offs are more functionally constrained and tend evolve slower interspecifically than those involved in facilitations or one-to-one relationships.

Data from: "Alternative phenotypes within mating systems" in The evolution of insect mating systems

Insects were for a long time considered simple organisms with unvarying behavioural repertoires, incapable of complicated behavioural responses to changing environments and/or social conditions. However, nothing could be further from the truth; phenotypic plasticity is widespread in insect development, life history, physiology, and behaviour (Whitman and Ananthakrishnan 2009). Plastic responses to environmental and social conditions are actually central to the remarkable adaptability of insects, and have played a crucial role in their evolutionary histories (Moczek 2010; Simpson et al. 2011). Moreover, phenotypic plasticity in insects is not merely restricted to simple responses in metabolism or activity to abiotic factors such as temperature, but can be extremely elaborate, an illuminating example of which is the learning ability of honeybees (Giurfa 2007; Hammer and Menzel 1995; Menzel 1993; Menzel and Muller 1996). Insect mating systems are no exception to this pattern. This chapter explores the intrasexual variation in behaviours and morphologies found in insect mating systems. More specifically, we focus on the evolution of the alternative means by which individuals obtain fertilizations, generally referred to as 'alternative mating tactics', or 'alternative mating phenotypes' (AMPs). The first studies to describe what we can interpret today as cases of AMPs in insects date back to at least the 1930s (Salt 1937), but it was only in the 1970s that the number of studies reporting this phenomenon started to accumulate. In 1983, when the classic examples of AMPs in digger bees and scorpionflies were reviewed by Thornhill and Alcock (1983), approximately 50 cases of AMPs in insects were already known, a number that has now surpassed the 200 mark. Here, we review the theoretical and empirical advances that have been made in this area since Thornhill and Alcock's volume. We start by describing two illustrative systems in detail, gryllid field crickets and onthophagine dung beetles. These two groups were chosen because their reproductive biology is well known, and because the contrasting degrees of behavioural plasticity and morphological specialisation between alternative phenotypes in these two groups illustrate the diversity of AMPs that has evolved in insects. We then discuss the genetic models that have been proposed to account for the evolution and maintenance of such dimorphisms, before reviewing the occurrence of AMPs in insects more generally. Finally, we discuss the relatively limited evidence for AMPs in female insects, a somewhat new and very promising area for future research.

Data from: Sweet tetra-trophic interactions: multiple evolution of nectar secretion, a defensive extended phenotype in cynipid gall wasps

Many herbivores employ reward-based mutualisms with ants to gain protection from natural enemies. We examine the evolutionary dynamics of a tetra-trophic interaction in which gall wasp herbivores induce their host oaks to produce nectar-secreting galls, which attract ants that provide protection from parasitoids. We show that, consistent with other gall defensive traits, nectar secretion has evolved repeatedly across the oak gall wasp tribe and also within a single genus (Disholcaspis) that includes many nectar-inducing species. Once evolved, nectar secretion is never lost in Disholcaspis, consistent with high defensive value of this trait. We also show that evolution of nectar secretion is correlated with a transition from solitary to aggregated oviposition, resulting in clustered nectar-secreting galls, which produce a resource that ants can more easily monopolize. Such clustering is commonly seen in ant guard mutualisms. We suggest that correlated evolution between maternal oviposition and larval nectar induction traits has enhanced the effectiveness of this gall defense strategy.

Data from: Maternal effects influence phenotypes and survival during early life stages in an aquatic turtle

Offspring phenotypic variation can be substantially influenced by non-genetic factors such as maternal effects, which ultimately can influence organismal fitness. For oviparous organisms that lack parental care, oviposition-site choice and egg size are maternal effects that can greatly affect offspring traits. Yet, few studies examine the consequences of these traits in the wild. We manipulated the contents of natural painted turtle nests such that offspring spent two life stages (incubation and hibernation) in either maternally-selected nest sites or randomly-selected nest sites, and quantified treatment differences in environmental parameters and offspring phenotypes. Additionally, we tracked the fates of individual eggs and hatchlings, which allowed us to quantify the strength and form of selection acting on egg size during incubation and, for the first time, body size during hibernation. Maternally-selected nest sites were warmer and produced offspring that were longer and hatched earlier than their siblings emerging from cooler, randomly-selected nests. Treatments did not affect any measured traits during hibernation. We detected no selection on egg size during the incubation stage, but significant linear selection favoring larger hatchlings during hibernation. Our results suggest that nest-site choice allows mothers to partially control the environment of their incubating eggs, but is less effective at controlling hatchling environments during hibernation. Additionally, we provide novel support for the "bigger-is-better" hypothesis in turtles by showing a positive relationship between size and survival during the hibernation stage.

Data from: Are thyroid hormones mediators of incubation temperature-induced phenotypes in birds?

Incubation temperature influences a suite of traits in avian offspring. However, the mechanisms underlying expression of these phenotypes are unknown. Given the importance of thyroid hormones in orchestrating developmental processes, we hypothesized that they may act as an upstream mechanism mediating the effects of temperature on hatchling phenotypic traits such as reduced growth and thermoregulation. We found that plasma T3, but not T4 concentrations, differed among newly-hatched wood ducks (Aix sponsa) from different embryonic incubation temperatures. T4 at hatching correlated with time spent hatching, and T3 correlated with hatchling body condition, tarsus length, time spent hatching, and incubation period. In addition, the T3:T4 ratio differed among incubation temperatures up at hatch. Our findings are consistent with the hypothesis that incubation temperature modulates plasma thyroid hormones which in turn influences multiple aspects of duckling phenotype.

Data from: Adaptive shaping of the behavioural and neuroendocrine phenotype during adolescence

Environmental conditions during early life can adaptively shape the phenotype for the prevailing environment. Recently, it has been suggested that adolescence represents an additional temporal window for adaptive developmental plasticity, though supporting evidence is scarce. Previous work has shown that male guinea pigs living in large mixed-sex colonies develop a low-aggressive phenotype as part of a queuing strategy that is adaptive for integrating into large unfamiliar colonies. By contrast, males living in pairs during adolescence become highly aggressive towards strangers. Here, we tested whether the high-aggressive phenotype is adaptive under conditions of low population density, namely when directly competing with a single opponent for access to females. For that purpose, we established groups of one pair-housed male (PM), one colony-housed male (CM) and two females. PMs directed more aggression towards the male competitor and more courtship and mating towards females than did CMs. In consequence, PMs attained the dominant position in most cases and sired significantly more offspring. Moreover, they showed distinctly higher testosterone concentrations and elevated cortisol levels, which probably promoted enhanced aggressiveness while mobilizing necessary energy. Taken together, our results provide the clearest evidence to date for adaptive shaping of the phenotype by environmental influences during adolescence.

Data from: Functional traits in red flour beetles: the dispersal phenotype is associated with leg length but not body size nor metabolic rate

Individuals vary in their ability to disperse. Much of this variation can be described by covarying phenotypic traits that are related to dispersal (constituting the 'dispersal phenotype' or 'dispersal syndrome'), but the nature of the associations among these traits is not well understood. Unravelling the associations among traits that potentially constitute the dispersal phenotype provides a foundation for understanding evolutionary trade-offs due to variation in dispersal. Here, we tested five predictions pertaining to the relationships among physiological, morphological and movement traits that are associated with dispersal, using a species with a long history as a laboratory model for studying ecological phenomena, red flour beetles (Tribolium castaneum). We identified a dominant axis of movement ability that describes variation in dispersal-related movement traits. Individuals that scored positively on this axis moved at higher speed, travelled longer distances, had lower movement intermittency and dispersed quicker to a specified area. Relative leg length, but not body size nor routine metabolic rate related positively with movement ability, indicating a likely mechanistic relationship between increased stride length and movement ability. Our data suggest that the dispersal phenotype may be more strongly linked to morphological traits than physiological ones. We demonstrate that associations among many functional traits do not necessarily conform to a priori expectations, and predict that the substantial intraspecific variation in trait values may be important for selection. Movement is a complex behavioural trait, but it has a mechanistic basis in locomotor morphology that warrants further exploration.

Data from: Theoretical conditions for the coexistence of viral strains with differences in phenotypic traits: a bifurcation analysis

We investigate the dynamics of a wild-type viral strain which generates mutant strains differing in phenotypic properties for infectivity, virulence, and mutation rates. We study, by means of a mathematical model and bifurcation analysis, conditions under which the wild-type and mutant viruses, which compete for the same host cells, can coexist. The coexistence conditions are formulated in terms of the basic reproductive numbers of the strains, a maximum value of the mutation rate, and the virulence of the pathogens. The analysis reveals that parameter space can be divided into five regions, each with distinct dynamics, that are organised around degenerate Bogdanov-Takens and zero-Hopf bifurcations, the latter of which gives rise to a curve of transcritical bifurcations of periodic orbits. These results provide new insights into the conditions by which viral populations may contain multiple coexisting strains in a stable manner.

Data from: Experimental evolution reveals balancing selection underlying coexistence of alternative male reproductive phenotypes

Heritable alternative reproductive phenotypes (ARPs), which differ in traits associated with competition for mates, occur across taxa. If polymorphism in the genes underlying ARPs is maintained by balancing selection, selection should return ARP proportions to their equilibrium if that equilibrium is perturbed. Here, we used an experimental evolution approach to directly test this prediction in male Rhizoglyphus robini, in which two heritable morphs occur: armoured fighters and more female-like, benign scramblers. Using selection lines nearly fixed for male morph, we constructed replicate populations consisting of 50% or 94% fighters, and allowed them to evolve for 14 generations in two types of environment: simple or spatially complex. We found that in both types of populations, the proportion of fighters converged on values within a narrow range of 0.70-0.83, although the rate of convergence was slower in the complex environment. Our results thus demonstrate balancing selection acting on polymorphism(s) underlying ARPs

Data from: There's no place like home: the contribution of direct and extended phenotypes on the expression of spider aggressiveness

Architectural constructions allow animals to modify their environment in order to improve their reproductive success. Constructions also modulate the expression of individual behavior, ultimately affecting the presence and importance of animal personality within populations. The exact impact of constructions on personality is seldom investigated. We quantified experimentally the impact of web characteristics on individual foraging behavior in the Western black widow spider (Latrodectus hesperus). We assayed aggressiveness toward a prey cue, and boldness while individuals resided on their own web versus after being translocated onto webs built by con-specifics. We quantified the importance of individual differences in aggressiveness and boldness while accounting for differences in web characteristics. We tested for relationships between web building, aggressiveness, and boldness. Web characteristics affected spider aggressiveness and interacted with individual web-building behavior to explain up to a fifth of the variation in foraging aggression, but did not affect spider boldness. Even after accounting for web characteristics, individuals still exhibited important differences in aggressiveness. We detected no relationship between an individual's aggressiveness behavioral type and the characteristics of the web it built. Surprisingly, web characteristics impacted aggressiveness differently from one individual to the next. Hence the effect of web characteristics on foraging behavior might depend on condition or past experience. Webs contributed mostly to the variation in aggressiveness within-individuals. Variation in web building behavior might affect the amount of consistent differences in foraging, mating, and anti-predator behavior among individuals and needs to be accounted for when quantifying individual variation in behavior in spiders.