Find research datasets worth reusing

Data from: Plastic expression of seminal fluid protein genes in a simultaneously hermaphroditic snail

Seminal fluid proteins (SFPs) are components of the ejaculate that often induce drastic changes in female physiology, such as reducing remating rate or shortening longevity. There is compelling evidence that these functions make SFPs a determinant of male reproductive success, and some evidence that males can strategically invest in their differential production. However, SFP-mediated effects have received relatively little attention in simultaneous hermaphrodites, i.e. organisms that are male and female at the same time. Since this reproductive mode is widespread in animals and their SFPs have unique functions compared to separate-sexed species, examining SFPs of hermaphrodites would help generalize our understanding of the impact of SFPs. We therefore examined if individuals strategically alter seminal fluid production in response to mate availability and sperm competition in the freshwater snail Lymnaea stagnalis. We exposed snails to different social group sizes, and measured the expression of six SFP genes. We found that the snails plastically elevated SFP expression in the presence of at least one mating partner. Specifically, paired snails showed higher SFP expression than isolated snails, while SFP expression of snails exposed to sperm competition, i.e. in a larger group size, was equivalent to that of paired snails. Furthermore, five out of six SFP genes we examined responded to mate availability in a very similar way, implying that overall seminal fluid production increases when the snails have mating opportunities. The plastic expression of seminal fluid depending on mate availability supports that SFPs play important roles in post-copulatory processes in this hermaphroditic species.

opencc-zeroDec 2016View details →

Data from: Bimodality of stable and plastic traits in plants

We challenged archived genetic mapping data for 36 fruit, seed, flower and yield traits in tomato and found an unexpected bimodal distribution in one measure of trait variability, the mean coefficient of variation, with some traits being consistently more variable than others. To determine the degree of conservation of this distribution among higher plants, we compared 18 homologous phenotypes, including yield and seed production, across different crop species grown in a common 'crop garden' experiment. The set included 32 varieties of tomato, eggplant, pepper, melon, watermelon, sunflower and maize. Estimates of canalization were obtained using a 'canalization replication' experimental design that generated multiple estimates of the coefficient of variation of traits, as well as their reaction norms in optimal and water-stressed field plots. A common pattern of bimodal distribution of stable and plastic traits was observed for all the varieties, and a wild weed (Solanum nigrum). We propose that canalization profiles of traits in a variety of taxa were ancestrally selected to maximize adaptation and reproductive success

Data from: DNA methylation mediates genetic variation for adaptive transgenerational plasticity

Environmental stresses experienced by individual parents can influence offspring phenotypes in ways that enhance survival under similar conditions. Although such adaptive transgenerational plasticity is well documented, its transmission mechanisms are generally unknown. One possible mechanism is environmentally induced DNA methylation changes. We tested this hypothesis in the annual plant Polygonum persicaria, a species known to express adaptive transgenerational plasticity in response to parental drought stress. Replicate plants of 12 genetic lines (sampled from natural populations) were grown in dry versus moist soil. Their offspring were exposed to the demethylating agent zebularine or to control conditions during germination and then grown in dry soil. Under control germination conditions, the offspring of drought-stressed parents grew longer root systems and attained greater biomass compared with offspring of well-watered parents of the same genetic lines. Demethylation removed these adaptive developmental effects of parental drought, but did not significantly alter phenotypic expression in offspring of well-watered parents. The effect of demethylation on the expression of the parental drought effect varied among genetic lines. Differential seed provisioning did not contribute to the effect of parental drought on offspring phenotypes. These results demonstrate that DNA methylation can mediate adaptive, genotype-specific effects of parental stress on offspring phenotypes.

Data from: Phenotypic plasticity of mate recognition systems prevents sexual interference between two sympatric leaf beetle species

Maladaptive sexual interactions among heterospecific individuals (sexual interference) can prevent the coexistence of animal species. Thus, the avoidance of sexual interference by divergence of mate recognition systems is crucial for a stable coexistence in sympatry. Mate recognition systems are thought to be under tight genetic control. However, we demonstrate that mate recognition systems of two closely related sympatric leaf beetle species show a high level of host-induced phenotypic plasticity. Mate choice in the mustard leaf beetles, Phaedon cochleariae and P. armoraciae, is mediated by cuticular hydrocarbons (CHCs). Divergent host plant use causes a divergence of CHC phenotypes, whereas similar host use leads to their convergence. Consequently, both species exhibit significant behavioral isolation when they feed on alternative host species, but mate randomly when using a common host. Thus, sexual interference between these syntopic leaf beetles is prevented by host-induced phenotypic plasticity rather than by genotypic divergence of mate recognition systems.

opencc-zeroDec 2010View details →

Data from: Does phenotypic plasticity for adult size versus food level in Drosophila melanogaster evolve in response to adaptation to different rearing densities?

Recent studies using inbred lines of Drosophila have suggested that there is extensive genetic variability for phenotypic plasticity of body size versus food level. If true, we expect that the outcome of evolution at very different food levels should yield genotypes whose adult sizes show different patterns of phenotypic plasticity. We have tested this prediction with six independent populations of Drosophila melanogaster kept at extreme (low vs. high) densities for 125 generations. We found that the phenotypic plasticity of body size versus food level is not affected by selection or the presence of competitors of a different genotype. However, we document increasing among population variation in phenotypic plasticity due to random genetic drift. Several reasons are explored to explain these results including the possibility that the use of highly inbred lines to make inferences about the evolution of genetically variable populations may be misleading.

opencc-zeroDec 2017View details →

Data from: Influence of interspecific competitors on behavioral thermoregulation: developmental or acute plasticity?

Many ectotherms reduce their exposure to changing thermal conditions using behavioral thermoregulation. The effectiveness of behavioral thermoregulation in maintaining ectotherm body temperatures within the target range is influenced not only by environmental (operative) temperatures but also by the presence of other con- and heterospecific individuals. How species' interactions affect behavioral thermoregulation is largely unknown. Theory predicts that species' interactions could affect the plasticity of behavioral thermoregulation in two ways, i.e. by developmental plasticity of a preferred temperature range or by an acute shift in body temperatures. Empirical tests of these predictions are scarce. We examined the developmental and acute effects of heterospecific social interactions on the accuracy and effectiveness of thermoregulation in larvae of two competing species, Ichthyosaura alpestris and Lissotriton vulgaris. The presence of heterospecifics during larval development had no effect on preferred body temperatures but it modified later acute thermoregulatory responses to heterospecifics. Ichthyosaura alpestris larvae from heterospecific tanks increased their thermoregulatory accuracy and effectiveness, while L. vulgaris larvae from conspecific tanks relaxed their thermoregulatory efforts. The thermal dependence of somatic growth suggests that modified behavioral thermoregulation has the potential to accelerate growth in competitively dominant I. alpestris. Acute thermoregulatory responses are affected by heterospecific social interactions in newt larvae, but not conspecific. A developmental plastic response modified body temperatures not the target thermoregulatory range, which shows that the influence of heterospecific social interactions is more complex than predicted by theory. Species interactions complicate estimating an ectotherm's vulnerability to ongoing climate change.

Data from: Individual variation in the social plasticity of water dragons

Individuals should alter when they socially associate with conspecifics to avoid potentially costly interactions. Moreover, individuals may vary in their propensity to use information about conspecifics when making such social decisions. However, surprisingly little is known about either the determinants of, or individual variation in, such 'social plasticity'. We show here that eastern water dragons (Intellegama lesueurii lesueurii) may simultaneously use information from different components of their social environment when deciding whether or not to socially associate. In particular, we found that individuals altered when they socially associated according to levels of potential conflict and competition in their social environment; both sexes socially associated more at higher local density than would be expected under increased random encounters. Further, females were more likely to socially associate during the breeding season, and when there were more males and/or conspecifics whom they typically avoided in their social environment. This suggests that females may seek safety in numbers when the potential for intra-sexual conflict or sexual harassment is high. Using a behavioural reaction-norm framework, we also provide novel evidence to show that individuals vary in the extent and direction of their social plasticity, and that males varied more than females. Our study thus implies that individuals use multiple cues in their environment when deciding to socially associate, and that the resulting social plasticity varies between the sexes and between individuals.

opencc-zeroDec 2013View details →

Data from: Evolution of phenotype-environment associations by genetic responses to selection and phenotypic plasticity in a temporally autocorrelated environment

Covariation between population-mean phenotypes and environmental variables, sometimes termed a 'phenotype-environment association' (PEA), can result from phenotypic plasticity, genetic responses to natural selection, or both. PEAs can potentially provide information on the evolutionary dynamics of a particular set of populations, but this requires a full theoretical characterization of PEAs and their evolution. Here, we derive formulas for the expected PEA in a temporally fluctuating environment for a quantitative trait with a linear reaction norm. We compare several biologically relevant scenarios, including constant versus evolving plasticity, and the situation where an environment affects both development and selection but at different time periods. We find that PEAs are determined not only by biological factors (e.g., magnitude of plasticity, genetic variation), but also environmental factors, such as the association between the environments of development and of selection, and in some cases the level of temporal autocorrelation. We also describe how a PEA can be used to estimate the relationship between an optimum phenotype and an environmental variable (i.e., the environmental sensitivity of selection), an important parameter for determining the extinction risk of populations experiencing environmental change. We illustrate this ability using published data on the predator-induced morphological responses of tadpoles to predation risk.

Data from: Prenatal exposure to predation affects predator recognition learning via lateralization plasticity

Prey with cerebral lateralization often shows a bias in escape direction and asymmetrical use of eyes for scanning. Such asymmetries are likely to cause ecological disadvantages when, for example, predators attack from the side in which the prey is more susceptible. However, lateralized individuals are diffuse in many species and, paradoxically, their frequency increases via developmental plasticity in environments with high-predation risk. Using wood frog tadpoles, Lithobates sylvaticus, we tested the hypothesis that cerebral lateralization enhances predator recognition learning and thus overcomes the costs of behavioral asymmetries in high predation risk environments. In the first experiment, we found tadpoles exposed to risk as embryos developed more intense lateralization in a rotational test compared to predator-naive controls. Risk exposure led to the more frequent development of clockwise swimming preference. In the second experiment, we found that tadpoles exhibiting no behavioral lateralization and tadpoles with marked clockwise swimming preference learned to recognize the novel predator odor, with the latter showing a better performance as predicted. Tadpoles with anticlockwise swimming preference did not learn to associate the predator with risk. Exposure to a high-risk environment during early ontogeny appears to favor the development of either a lateralization phenotype with refined predator recognition learning skills, or, to a lesser extent, a lateralization phenotype with poor predator recognition learning skills. Such individuals likely cope with predation using mechanisms other than learning.

opencc-zeroDec 2017View details →

Data from: Multiple simultaneous treatments change plant response from adaptive parental effects to within-generation plasticity, in Arabidopsis thaliana

In general, studies on plant phenotypic plasticity concentrate on plant responses to different levels of a single environmental factor. Under natural conditions, however, multiple environmental factors often vary simultaneously. I studied the consequences for lifetime fitness caused by single treatments or treatment combinations by investigating patterns of phenotypic plasticity within and between generations. The parental plants (3 genotypes of the annual plant Arabidopsis thaliana) received zero, one or two stress treatments at an early life-stage. The treatments included wounding, shading, chilling, and their pairwise combinations. In the second generation, offspring of treated plants received either the parental or no treatment. Offspring of non-treated plants were reared under all treatment conditions. Plants responded strongly to the treatments, especially through delayed reproduction, which positively affected lifetime fitness. Notably, treatment combinations triggered stronger plastic responses on average. Because the delay in reproduction was offset by a delay in senescence, the treatments resulted in a fitness gain instead of a loss. However, under adverse environmental conditions, this delay represents a potential fitness cost, especially when the time for reproduction is limited. The treatments wounding and shading triggered parental effects that increased fitness only in plants that themselves received the treatment. Untreated offspring of wounded or shaded parents performed like control plants. Also, these parental effects were not accompanied by potential fitness costs, such as delayed reproduction. Chilling triggered genotype-specific parental effects that increased or reduced fitness. Of the treatment combinations only wounding and shading resulted in genotype-specific parental effects that increased or reduced fitness independently of offspring treatment. These results suggest that the response of annual plants to treatment combinations triggers predominantly within-generation plastic responses that include potential fitness costs, which cannot be inferred from studies that manipulate environmental factors individually. Therefore, single treatment studies likely underestimate the costs of plasticity in natural environments.

opencc-zeroJul 2019View details →

Data from: Reverting ontogeny: rapid phenotypic plasticity of color vision in cichlid fish

Phenotypic plasticity, particularly during development, allows organisms to rapidly adjust to different environmental conditions. Yet, it is often unclear whether the extent and direction of plastic changes are restricted by an individual's ontogeny. Many species of cichlid fishes go through ontogenetic changes in visual sensitivity, from short to long wavelengths, by switching expression of cone opsin genes crucial for color vision. During this progression, individuals often exhibit phenotypic plasticity to the ambient light conditions. However, it is commonly assumed that once an adult visual phenotype is reached, reverting to an earlier ontogenetic state with higher sensitivity at shorter wavelengths is not common. In this study, we experimentally demonstrate that four-month-old Midas cichlid fish (Amphilophus astorquii) show plasticity in single cone opsin expression after experiencing drastic changes in light conditions. Resulting shifts of visual sensitivity occurred presumably in an adaptive direction - towards shorter or longer wavelengths when exposed to short or long wavelength light, respectively. Single cone opsin expression changed within only a few days and went through a transitional phase of co-expression. When the environment was experimentally enriched in long wavelength light, the corresponding change occurred gradually along a dorsoventral gradient within the retina. This plasticity allowed individuals to revert earlier ontogenetic changes and return to a more juvenile visual phenotype demonstrating previously unrecognized insights into temporal and spatial dynamics of phenotypic plasticity of the visual system in response to ambient light.

opencc-zeroDec 2017View details →

Data from: A study of the transit amplification divisions during spermatogenesis in Oncopeltus fasciatus to assess plasticity in sperm numbers or sperm viability under different diets

Oncopeltus fasciatus males fed the ancestral diet of milkweed seeds prioritize reproduction over lifespan as evidenced by higher rates of fertility and shorter lifespans than males from the same population fed the adapted diet of sunflower seeds. We examined the proximate mechanisms by which milkweed-fed males maintained late-life fertility. We tested the hypothesis that older milkweed-fed males maintained fertility by producing more, higher quality sperm. Our results, that older males have more sperm, but their sperm do not have higher viability, is in general agreement with other recent studies on how nutrition affects male fertility in insects. We further examined the mechanisms by which sperm are produced by examining the progression of spermatogonial cells through the cell cycle during the transit amplification divisions. We demonstrated that diet affects the likelihood of a spermatocyst being in the S-phase or M-phase of the cell cycle. Given work in model systems, these results have implications for subtle effects on sperm quality either through replication stress or epigenetic markers. Thus, viability may not be the best marker for sperm quality and more work is called for on the mechanisms by which the germline and the production of sperm mediate the cost of reproduction.

opencc-zeroOct 2019View details →

Populations of a widespread invader and co-occurring native species vary in phenotypic plasticity

Phenotypic plasticity can promote plant invasions and enhance impacts on native species but little is known about variation in plasticity among invader populations compared to native species. Variation in plasticity among invader populations could inform more precise predictions of invader spread and impacts across heterogeneous resource environments. We used a common garden experiment with sun and shade treatments to test for variation in plasticity among 12 populations of an invasive grass, and to determine if the invader exhibited greater plasticity than six native species that co-occur in the Southeast US. Principal component analysis revealed that invader populations from different native ranges consistently varied from each other and native species in traits linked to more favorable phenotypes under resource limitation. Overall, the invader exhibited greater plasticity than native species, as demonstrated by higher plasticity index values for traits such as plant height, leaf mass ratio, and root shoot ratio. Variation in phenotypic plasticity among invader populations suggests the potential for evolution of plasticity, and greater plasticity of invader populations than native species may underlie invader dominance. Differences in plasticity among populations appears to play an important role in predictions of the spread and potentially the impacts of invasive species.

Data from: Nutrient starvation impairs the trophic plasticity of reef-building corals under ocean warming

1) Global warming of the world's oceans is driving reef-building corals towards their upper thermal limit, inducing bleaching, nutrient starvation and mortality. In addition, corals are predicted to experience large fluctuations in seawater nutrient concentrations, following water column stratification or eutrophication problems, which can further alter their nutritional capacities and ultimately their resilience to global change. 2) We investigated the effect of thermal stress and dissolved inorganic nutrient (DINUT) availability on the auto- and heterotrophic nutritional capacities of corals. In particular, we assessed the effect of nitrogen enrichment or DINUT depletion (both in nitrogen and phosphorus) on the assimilation of heterotrophic nutrients as well as on the heat-stress tolerance of the reef-building coral Stylophora pistillata. 3) Here, we show that DINUT depletion enhanced coral bleaching under thermal stress and more importantly, significantly impaired rates of heterotrophic nutrient assimilation, inducing coral starvation. In contrast, corals grown under nitrogen enrichment maintained high rates of heterotrophic nutrient assimilation and avoided bleaching, although nutrient uptake rates were lowered. We therefore observed a positive coupling between auto-and heterotrophy within the coral-dinoflagellate symbiosis, indicating that heterotrophic processes require a minimum of autotrophically-acquired nutrients to be functional. 4) These findings show that the trophic plasticity of corals directly depends on the availability of dissolved inorganic nutrients in seawater. The lack of a shift toward greater heterotrophy under DINUT depletion may lead to substantial modifications of the role that feeding plays in the response of reef-building corals to climate change.

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: Temperature-induced developmental plasticity in Plodia interpunctella: reproductive behaviour and sperm length.

In both plants and animals, male gametogenesis is particularly sensitive to heat stress, to the extent that a single hot or cold day can compromise crop productivity or population persistence. In animals, heat stress during development can impact a male's ability to secure copulations and/or his post-copulatory fertility. Despite such observations, relatively few studies have examined the consequences of developmental temperature on the reproductive behaviour and physiology of individuals. Here we report for the first time the effects of developmental temperature on the phenotypic expression of both apyrene and eupyrene sperm and the copulatory behaviour of the Indian meal moth, Plodia interpunctella. We show that the length of both apyrene and eupyrene sperm decrease with increasing developmental temperature and that males are less likely to engage in copulation when reared at the highest and lowest temperatures. Where copulation occurred, the duration of copula decreased as male developmental temperature increased. We argue that identification of the mechanisms and consequences of reproductive failure in animals facing heat stress will help understand how wild and domesticated populations will respond to global climate change. We also contend that such studies will help elucidate long-standing evolutionary questions around the maintenance of genetic variation in traits highly relevant to fitness and the role of phenotypic plasticity in driving the evolution of novel traits.

opencc-zeroDec 2016View details →

Data from: Vocal plasticity in mallards: multiple signal changes in noise and the evolution of the Lombard effect in birds

Signal plasticity is a building block of complex animal communication systems. A particular form of signal plasticity is the Lombard effect, in which a signaler increases its vocal amplitude in response to an increase in the background noise. The Lombard effect is a basic mechanism for communication in noise that is well-studied in human speech and which has also been reported in other mammals and several bird species. Sometimes, but not always, the Lombard effect is accompanied by additional changes in signal parameters. However, the evolution of the Lombard effect and other related vocal adjustments in birds are still unclear because so far only three major avian clades have been studied. We report the first evidence for the Lombard effect in an anseriform bird, the mallard (Anas platyrhynchos). In association with the Lombard effect, the fifteen ducklings in our experiment also increased the peak frequency of their calls in noise. However, they did not change the duration of call syllables or their call rates as has been found in other bird species. Our findings support the notion that all extant birds use the Lombard effect to solve the common problem of maintaining communication in noise, i.e. it is an ancestral trait shared among all living avian taxa, which means that it has evolved more than 70 million years ago within that group. At the same time, our data suggest that parameter changes associated with the Lombard effect follow more complex patterns, with marked differences between taxa, some of which might be related to proximate constraints..

opencc-zeroDec 2016View details →

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: Exploring visual plasticity: dietary carotenoids can change color vision in guppies (Poecilia reticulata)

Differences in color vision can play a key role in an organism's ability to perceive and interact with the environment across a broad range of taxa. Recently, species have been shown to vary in color vision across populations as a result of differences in regulatory sequence and/or plasticity of opsin gene expression. For decades, biologists have been intrigued by among-population variation in color-based mate preferences of female Trinidadian guppies. We proposed that some of this variation results from variation in color vision caused by plasticity in opsin expression. Specifically, we asked about the role of dietary carotenoid availability, because carotenoids (1) are the precursors for vitamin A, which is essential for the creation of photopigments and (2) have been linked to variation in female mate choice. We raised guppies on different carotenoid-level diets and measured opsin expression. Guppies raised on high-carotenoid diets expressed higher levels of long wavelength sensitive opsin (LWS) opsins than those raised on lower levels of carotenoids. These results suggest that dietary effects on opsin expression represent a previously unaccounted for mechanism by which ecological differences across populations could lead to mate choice differences.