Unraveling biotypes of the northern house mosquito, Culex pipiens s.l. (Diptera: Culicidae): molecular differentiation and morphometric analysis.

Geometric morphometrics was used to determine whether geographic isolation could explain differences in wing size and shape between and within continental (27°S to 41°S) and insular (Rapa Nui) populations of Culex pipiens s.s. Linnaeus and their biotypes (f. pipiens and f. molestus). Molecular protocols based on polymorphisms in the second intron of nuclear locus ace-2 (acetylcholinesterase-2) were used to differentiate Cx. pipiens s.s. from Cx. quinquefasciatus Say, and an assay based on polymorphisms in the flanking region of a microsatellite locus (CQ11) was used to identify biotypes. Culex pipiens f. molestus and hybrids shared larval habitats in all continental sites, while Cx. pipiens f. pipiens was found in 5 of the 10 sites. Only biotype molestus was found in Rapa Nui (Easter Island) Pipiens and molestus biotypes occur sympatrically in aboveground locations, and only molestus was found in the underground site (ME). Biotype molestus was dominant in rural locations and preferably anthropophilic. These results agree with the ecological descriptions previously reported for the biotypes of Cx. pipiens s.s. Procrustes ANOVA only showed differences in centroid size between biotypes in females and males and did not show significant differences in wing shape. However, we found significant differences among the geographic areas in the centroid size and wing shape of both females and males. Particularly, the population of Rapa Nui Island had shorter wings than the continental populations. The results highlight the effects of geographic and environmental processes on morphotypes in vector mosquitoes.

Altered wing phenotypes of captive-bred migratory birds lower post-release fitness.

Captive breeding and release to the wild is a globally important conservation tool. However, captivity can result in phenotypic changes that incur post-release fitness costs, especially if they affect strenuous or risky behaviours. Bird wing shape is critical for migration success and suboptimal phenotypes are strongly selected against. In this study, I demonstrate surprising plasticity of bird wing phenotypes in captivity for 4/16 studied species. In a model species, captive-born juveniles with wild wing phenotypes (a 1-mm longer distal primary flight feather) survived post-release at 2.7 times the rate of those with captive phenotypes (i.e. a shorter distal feather). Subtle phenotypic changes and their fitness impacts are more common than widely realised because they are easily overlooked. To improve captive breeding for conservation, practitioners must surveil phenotypic changes and find ways to mitigate them.

Experimental Evidence That Phenotypic Evolution but Not Plasticity Occurs along Genetic Lines of Least Resistance in Homogeneous Environments.

AbstractGenetic correlations concentrate genetic variation in certain directions of the multivariate phenotype. Adaptation and, under some models, plasticity is expected to occur in the direction of the phenotype containing the greatest amount of genetic variation (gmax). However, this may hinge on environmental heterogeneity, which can affect patterns of genetic variation. I use experimental evolution to test whether plasticity and phenotypic evolution follow gmax during adaptation to environments that varied in environmental heterogeneity. For >25 generations, Drosophila melanogaster populations were exposed to six homogeneous or spatially and temporally heterogeneous treatments involving hot (25°C) and cold (16°C) temperatures. Five wing traits were assayed in both temperatures. Wing morphology diverged between populations evolving in homogeneous hot and cold temperatures in a direction of the phenotype containing a large proportion of genetic variance and that aligned closely with gmax at 16°C but not at 25°C. Spatial heterogeneity produced an intermediate phenotype, which was associated with similar genetic variance across assay temperatures compared with all other treatments. Surprisingly, plasticity across assay temperatures was in a different direction to phenotypic evolution and aligned better with maternal variance than gmax. Together, these results provide experimental evidence for evolution along genetic lines of least resistance in homogeneous environments but no support for predicting plastic responses from the orientation of genetic variation. These results also suggest that spatial heterogeneity could maintain genetic variation that increases the stability of genetic variance across environments.

Allometric wing growth links parental care to pterosaur giantism.

Pterosaurs evolved a broad range of body sizes, from small-bodied early forms with wingspans of mostly 1-2 m to the last-surviving giants with sizes of small airplanes. Since all pterosaurs began life as small hatchlings, giant forms must have attained large adult sizes through new growth strategies, which remain largely unknown. Here we assess wing ontogeny and performance in the giant Pteranodon and the smaller-bodied anurognathids Rhamphorhynchus, Pterodactylus and Sinopterus. We show that most smaller-bodied pterosaurs shared negative allometry or isometry in the proximal elements of the fore- and hindlimbs, which were critical elements for powering both flight and terrestrial locomotion, whereas these show positive allometry in Pteranodon. Such divergent growth allometry typically signals different strategies in the precocial-altricial spectrum, suggesting more altricial development in Pteranodon. Using a biophysical model of powered and gliding flight, we test and reject the hypothesis that an aerodynamically superior wing planform could have enabled Pteranodon to attain its larger body size. We therefore propose that a shift from a plesiomorphic precocial state towards a derived state of enhanced parental care may have relaxed the constraints of small body sizes and allowed the evolution of derived flight anatomies critical for the flying giants.

Mixed support for an alignment between phenotypic plasticity and genetic differentiation in damselfly wing shape.

The relationship between genetic differentiation and phenotypic plasticity can provide information on whether plasticity generally facilitates or hinders adaptation to environmental change. Here, we studied wing shape variation in a damselfly (Lestes sponsa) across a latitudinal gradient in Europe that differed in time constraints mediated by photoperiod and temperature. We reared damselflies from northern and southern populations in the laboratory using a reciprocal transplant experiment that simulated time-constrained (i.e. northern) and unconstrained (southern) photoperiods and temperatures. After emergence, adult wing shape was analysed using geometric morphometrics. Wings from individuals in the northern and southern populations differed significantly in shape when animals were reared in their respective native environment. Comparing wing shape across environments, we found evidence for phenotypic plasticity in wing shape, and this response differed across populations (i.e. G × E interactions). This interaction was driven by a stronger plastic response by individuals from the northern population and differences in the direction of plastic wing shape changes among populations. The alignment between genetic and plastic responses depended on the specific combination of population and rearing environment. For example, there was an alignment between plasticity and genetic differentiation under time-constrained, but not under non-time-constrained conditions for forewings. We thus find mixed support for the hypothesis that environmental plasticity and genetic population differentiation are aligned. Furthermore, although our laboratory treatments mimicked the natural climatic conditions at northern and southern latitudes, the effects of population differences on wing shape were two to four times stronger than plastic effects. We discuss our results in terms of time constraints and the possibility that natural and sexual selection is acting differently on fore- and hindwings.

Adaptive shifts underlie the divergence in wing morphology in bombycoid moths.

The evolution of flapping flight is linked to the prolific success of insects. Across Insecta, wing morphology diversified, strongly impacting aerodynamic performance. In the presence of ecological opportunity, discrete adaptive shifts and early bursts are two processes hypothesized to give rise to exceptional morphological diversification. Here, we use the sister-families Sphingidae and Saturniidae to answer how the evolution of aerodynamically important traits is linked to clade divergence and through what process(es) these traits evolve. Many agile Sphingidae evolved hover feeding behaviours, while adult Saturniidae lack functional mouth parts and rely on a fixed energy budget as adults. We find that Sphingidae underwent an adaptive shift in wing morphology coincident with life history and behaviour divergence, evolving small high aspect ratio wings advantageous for power reduction that can be moved at high frequencies, beneficial for flight control. By contrast, Saturniidae, which do not feed as adults, evolved large wings and morphology which surprisingly does not reduce aerodynamic power, but could contribute to their erratic flight behaviour, aiding in predator avoidance. We suggest that after the evolution of flapping flight, diversification of wing morphology can be potentiated by adaptative shifts, shaping the diversity of wing morphology across insects.

Genomics of altitude-associated wing shape in two tropical butterflies.

Understanding how organisms adapt to their local environment is central to evolution. With new whole-genome sequencing technologies and the explosion of data, deciphering the genomic basis of complex traits that are ecologically relevant is becoming increasingly feasible. Here, we studied the genomic basis of wing shape in two Neotropical butterflies that inhabit large geographical ranges. Heliconius butterflies at high elevations have been shown to generally have rounder wings than those in the lowlands. We reared over 1,100 butterflies from 71 broods of H. erato and H. melpomene in common-garden conditions and showed that wing aspect ratio, that is, elongatedness, is highly heritable in both species and that elevation-associated wing aspect ratio differences are maintained. Genome-wide associations with a published data set of 666 whole genomes from across a hybrid zone, uncovered a highly polygenic basis to wing aspect ratio variation in the wild. We identified several genes that have roles in wing morphogenesis or wing aspect ratio variation in Drosophila flies, making them promising candidates for future studies. There was little evidence for molecular parallelism in the two species, with only one shared candidate gene, nor for a role of the four known colour pattern loci, except for optix in H. erato. Thus, we present the first insights into the heritability and genomic basis of within-species wing aspect ratio in two Heliconius species, adding to a growing body of evidence that polygenic adaptation may underlie many ecologically relevant traits.

Punctuational ecological changes rather than global factors drive species diversification and the evolution of wing phenotypes in Morpho butterflies.

Assessing the relative importance of geographical and ecological drivers of evolution is paramount to understand the diversification of species and traits at the macroevolutionary scale. Here, we use an integrative approach, combining phylogenetics, biogeography, ecology and quantified phenotypes to investigate the drivers of both species and phenotypic diversification of the iconic Neotropical butterfly genus Morpho. We generated a time-calibrated phylogeny for all known species and inferred historical biogeography. We fitted models of time-dependent (accounting for rate heterogeneity across the phylogeny) and paleoenvironment-dependent diversification (accounting for global effect on the phylogeny). We used geometric morphometrics to assess variation of wing size and shape across the tree and investigated their dynamics of evolution. We found that the diversification of Morpho is best explained when considering variable diversification rates across the tree, possibly associated with lineages occupying different microhabitat conditions. First, a shift from understory to canopy was characterized by an increased speciation rate partially coupled with an increasing rate of wing shape evolution. Second, the occupation of dense bamboo thickets accompanying a major host-plant shift from dicotyledons towards monocotyledons was associated with a simultaneous diversification rate shift and an evolutionary 'jump' of wing size. Our study points to a diversification pattern driven by punctuational ecological changes instead of a global driver or biogeographic history.

Hybridization and transgressive exploration of colour pattern and wing morphology in Heliconius butterflies.

Hybridization can generate novel phenotypes distinct from those of parental lineages, a phenomenon known as transgressive trait variation. Transgressive phenotypes might negatively or positively affect hybrid fitness, and increase available variation. Closely related species of Heliconius butterflies regularly produce hybrids in nature, and hybridization is thought to play a role in the diversification of novel wing colour patterns despite strong stabilizing selection due to interspecific mimicry. Here, we studied wing phenotypes in first- and second-generation hybrids produced by controlled crosses between either two co-mimetic species of Heliconius or between two nonmimetic species. We quantified wing size, shape and colour pattern variation and asked whether hybrids displayed transgressive wing phenotypes. Discrete traits underlain by major-effect loci, such as the presence or absence of colour patches, generate novel phenotypes. For quantitative traits, such as wing shape or subtle colour pattern characters, hybrids only exceed the parental range in specific dimensions of the morphological space. Overall, our study addresses some of the challenges in defining and measuring phenotypic transgression for multivariate traits and our data suggest that the extent to which transgressive trait variation in hybrids contributes to phenotypic diversity depends on the complexity and the genetic architecture of the traits.

Genome-wide association analysis of host genotype and plastic wing morphological variation of an endoparasitoid wasp Asobara japonica (Hymenoptera: Braconidae).

Accumulating evidence suggests that genotype of host insects influences the development of koinobiont endoparasitoids. Although there are many potential genetic variations that lead to the internal body environmental variations of host insects, association between the host genotype and the parasitoid development has not been examined in a genome-wide manner. In the present study, we used highly inbred whole genome sequenced strains of Drosophila melanogaster to associate single nucleotide polymorphisms (SNPs) of host flies with morphological traits of Asobara japonica, a larval-pupal parasitoid wasp that infected those hosts. We quantified the outline shape of the forewings of A. japonica with two major principal components (PC1 and PC2) calculated from Fourier coefficients obtained from elliptic Fourier analysis. We also quantified wing size and estimated wasp survival. We then examined the association between the PC scores, wing size and 1,798,561 SNPs and  the association between the estimated wasp survival and 1,790,544 SNPs. As a result, we obtained 22, 24 and 14 SNPs for PC1, PC2 and wing size and four SNPs for the estimated survival with P values smaller than 10-5. Based on the location of the SNPs, 12, 17, 11 and five protein coding genes were identified as potential candidates for PC1, PC2, wing size and the estimated survival, respectively. Based on the function of the candidate genes, it is suggested that the host genetic variation associated with the cell growth and morphogenesis may influence the wasp's morphogenetic variation.

Phenotypic plasticity of Drosophila suzukii wing to developmental temperature: implications for flight.

Phenotypic plasticity has been proposed as a mechanism that facilitates the success of biological invasions. In order to test the hypothesis of an adaptive role for plasticity in invasions, particular attention should be paid to the relationship between the focal plastic trait, the environmental stimulus and the functional importance of the trait. The Drosophila wing is particularly amenable to experimental studies of phenotypic plasticity. Wing morphology is known for its plastic variation under different experimental temperatures, but this plasticity has rarely been investigated in a functional context of flight. Here, we investigate the effect of temperature on wing morphology and flight in the invasive pest species Drosophila suzukii Although the rapid invasion of both Europe and North America was most likely facilitated by human activities, D. suzukii is also expected to disperse actively. By quantifying wing morphology and individual flight trajectories of flies raised under different temperatures, we tested whether (1) invasive populations of D. suzukii show higher phenotypic plasticity than their native counterparts, and (2) wing plasticity affects flight parameters. Developmental temperature was found to affect both wing morphology and flight parameters (in particular speed and acceleration), leaving open the possibility of an adaptive value for wing plasticity. Our results show no difference in phenotypic plasticity between invasive and native populations, rejecting a role for wing plasticity in the invasion success.

Fiber Bragg Gratings Sensors for Aircraft Wing Shape Measurement: Recent Applications and Technical Analysis.

The safety monitoring and tracking of aircraft is becoming more and more important. Under aerodynamic loading, the aircraft wing will produce large bending and torsional deformation, which seriously affects the safety of aircraft. The variation of load on the aircraft wing directly affects the ground observation performance of the aircraft baseline. To compensate for baseline deformations caused by wing deformations, it is necessary to accurately obtain the deformation of the wing shape. The traditional aircraft wing shape measurement methods cannot meet the requirements of small size, light weight, low cost, anti-electromagnetic interference, and adapting to complex environment at the same time, the fiber optic sensing technology for aircraft wing shape measurement has been gradually proved to be a real time and online dynamic measurement method with many excellent characteristics. The principle technical characteristics and bonding technology of fiber Bragg grating sensors (FBGs) are reviewed in this paper. The advantages and disadvantages of other measurement methods are compared and analyzed and the application status of FBG sensing technology for aircraft wing shape measurement is emphatically analyzed. Finally, comprehensive suggestions for improving the accuracy of aircraft wing shape measurement based on FBG sensing technology is put forward.

Wing shape-mediated carry-over effects of a heat wave during the larval stage on post-metamorphic locomotor ability.

Two key insights to better assess the ecological impact of global warming have been poorly investigated to date: global warming effects on the integrated life cycle and effects of heat waves. We tested the effect of a simulated mild (25 °C) and severe (30 °C) heat wave experienced during the larval stage on the flight ability of the damselfly Ischnura elegans. To get a mechanistic understanding of how heat stress may translate into reduced post-metamorphic flight ability, we evaluated the hypothesized mediatory role of adult size-related traits, and also tested alternative pathways operating through changes in wing shape and two flight-related traits (both relative fat and flight muscle contents). Exposure to a heat wave, and particularly the severe one, shortened the larval stage, reduced adult size-related traits and modified the wing shape but did not significantly affect emergence success, relative fat content and relative flight muscle mass. Notably, the heat wave negatively affected all components of flight ability. Unexpectedly, the heat wave did not reduce flight ability through reducing size. Instead, we identified a novel size-independent mechanism bridging metamorphosis to link larval environment and adult flight ability in males: through affecting wing shape. The present study advances mechanistic insights in the still poorly understood coupling of life stages across metamorphosis. Additionally, our results underscore the need for integrative studies across life stages to understand the impact of global warming.

Flight feather attachment in rock pigeons (Columba livia): covert feathers and smooth muscle coordinate a morphing wing.

Mechanisms for passively coordinating forelimb movements and flight feather abduction and adduction have been described separately from both in vivo and ex vivo studies. Skeletal coordination has been identified as a way for birds to simplify the neuromotor task of controlling flight stroke, but an understanding of the relationship between skeletal coordination and the coordination of the aerodynamic control surface (the flight feathers) has been slow to materialize. This break between the biomechanical and aerodynamic approaches - between skeletal kinematics and airfoil shape - has hindered the study of dynamic flight behaviors. Here I use dissection and histology to identify previously overlooked interconnections between musculoskeletal elements and flight feathers. Many of these structures are well-placed to directly link elements of the passive musculoskeletal coordination system with flight feather movements. Small bundles of smooth muscle form prominent connections between upper forearm coverts (deck feathers) and the ulna, as well as the majority of interconnections between major flight feathers of the hand. Abundant smooth muscle may play a role in efficient maintenance of folded wing posture, and may also provide an autonomically regulated means of tuning wing shape and aeroelastic behavior in flight. The pattern of muscular and ligamentous linkages of flight feathers to underlying muscle and bone may provide predictable passive guidance for the shape of the airfoil during flight stroke. The structures described here provide an anatomical touchstone for in vivo experimental tests of wing surface coordination in an extensively researched avian model species.

Is the morphology of Culicoides intersexes parasitized by mermithid nematodes a parasite adaptation? A morphometric approach to Culicoides circumscriptus (Diptera: Ceratopogonidae).

Mermithidae is a family of endoparasitic nematodes known to cause intersexuality in arthropods. Intersexes of the genus Culicoides parasitized by mermithids have been the object of several studies aiming to describe their particular morphology. Culicoides intersexes are specimens with male genitalia and feminized sexually dimorphic structures, i.e. antennae, mouthparts and wings. To date, these specimens have only been described qualitatively and a quantitative approach supported by statistical analysis is lacking. Here we conduct morphometric analyses of sexually dimorphic structures in a sample of Culicoides circumscriptus that includes 34 intersexes with the aim of describing precisely the intersexual morphology. The morphology of antennae and the mouthparts was studied by multivariate statistical analysis of linear measures, and wing form by implementing geometric morphometrics techniques. While intersex wings proved to have a similar size to male wings, their shape was intermediate between males and females. However, when allometric shape variation was removed, the wing shape of intersexes was almost identical to that of females. The intersex antennae were morphometrically of the female type, especially when size variation was considered. In contrast, the measured mouthparts (the labrum and the third palpal segment) were halfway between males and females, even when body size was considered. Overall, the antennae and the wings showed a higher degree of feminization than the mouthparts. These findings indicate that the degree of feminization depends both on the morphological structure and on body size. Moreover, we propose that the feminization of the wings and antennae has an adaptive meaning for the parasite, which would favor female-like traits in order to access more easily its breeding sites, where the parasite has plenty of new hosts to infect. Female-like antennae would be beneficial to detect these sites, while having female-like wings would favor the host's capacity of dispersal to these sites.

The evolution of avian wing shape and previously unrecognized trends in covert feathering.

Avian wing shape has been related to flight performance, migration, foraging behaviour and display. Historically, linear measurements of the feathered aerofoil and skeletal proportions have been used to describe this shape. While the distribution of covert feathers, layered over the anterior wing, has long been assumed to contribute to aerofoil properties, to our knowledge no previous studies of trends in avian wing shape assessed their variation. Here, these trends are explored using a geometric-morphometric approach with landmarks describing the wing outline as well as the extent of dorsal and ventral covert feathers for 105 avian species. We find that most of the observed variation is explained by phylogeny and ecology but shows only a weak relationship with previously described flight style categories, wing loading and an investigated set of aerodynamic variables. Most of the recovered variation is in greater primary covert feather extent, followed by secondary feather length and the shape of the wing tip. Although often considered a plastic character strongly linked to flight style, the estimated ancestral wing morphology is found to be generally conservative among basal parts of most major avian lineages. The radiation of birds is characterized by successive diversification into largely distinct areas of morphospace. However, aquatic taxa show convergence in feathering despite differences in flight style, and songbirds move into a region of morphospace also occupied by basal taxa but at markedly different body sizes. These results have implications for the proposed inference of flight style in extinct taxa.

Wing trait-inversion associations in Drosophila subobscura can be generalized within continents, but may change through time.

Clinal variation is one of the most emblematic examples of the action of natural selection at a wide geographical range. In Drosophila subobscura, parallel clines in body size and inversions, but not in wing shape, were found in Europe and South and North America. Previous work has shown that a bottleneck effect might be largely responsible for differences in wing trait-inversion association between one European and one South American population. One question still unaddressed is whether the associations found before are present across other populations of the European and South American clines. Another open question is whether evolutionary dynamics in a new environment can lead to relevant changes in wing traits-inversion association. To analyse geographical variation in these associations, we characterized three recently laboratory founded D. subobscura populations from both the European and South American latitudinal clines. To address temporal variation, we also characterized the association at a later generation in the European populations. We found that wing size and shape associations can be generalized across populations of the same continent, but may change through time for wing size. The observed temporal changes are probably due to changes in the genetic content of inversions, derived from adaptation to the new, laboratory environment. Finally, we show that it is not possible to predict clinal variation from intrapopulation associations. All in all this suggests that, at least in the present, wing traits-inversion associations are not responsible for the maintenance of the latitudinal clines in wing shape and size.

Cruising the rain forest floor: butterfly wing shape evolution and gliding in ground effect.

Flight is a key innovation in the evolutionary success of insects and essential to dispersal, territoriality, courtship and oviposition. Wing shape influences flight performance and selection likely acts to maximize performance for conducting essential behaviours that in turn results in the evolution of wing shape. As wing shape also contributes to fitness, optimal shapes for particular flight behaviours can be assessed with aerodynamic predictions and placed in an ecomorphological context. Butterflies in the tribe Haeterini (Nymphalidae) are conspicuous members of understorey faunas in lowland Neotropical forests. Field observations indicate that the five genera in this clade differ in flight height and behaviour: four use gliding flight at the forest floor level, and one utilizes flapping flight above the forest floor. Nonetheless, the association of ground level gliding flight behaviour and wing shape has never been investigated in this or any other butterfly group. We used landmark-based geometric morphometrics to test whether wing shapes in Haeterini and their close relatives reflected observed flight behaviours. Four genera of Haeterini and some distantly related Satyrinae showed significant correspondence between wing shape and theoretical expectations in performance trade-offs that we attribute to selection for gliding in ground effect. Forewing shape differed between sexes for all taxa, and male wing shapes were aerodynamically more efficient for gliding flight than corresponding females. This suggests selection acts differentially on male and female wing shapes, reinforcing the idea that sex-specific flight behaviours contribute to the evolution of sexual dimorphism. Our study indicates that wing shapes in Haeterini butterflies evolved in response to habitat-specific flight behaviours, namely gliding in ground effect along the forest floor, resulting in ecomorphological partitions of taxa in morphospace. The convergent flight behaviour and wing morphology between tribes of Satyrinae suggest that the flight environment may offset phylogenetic constraints. Overall, this study provides a basis for exploring similar patterns of wing shape evolution in other taxa that glide in ground effect.

Phylogeography and phenotypic wing shape variation in a damselfly across populations in Europe.

BACKGROUND: Describing geographical variation in morphology of organisms in combination with data on genetic differentiation and biogeography can provide important information on how natural selection shapes such variation. Here we study genetic structure using ddRAD seq and wing shape variation using geometric morphometrics in 14 populations of the damselfly Lestes sponsa along its latitudinal range in Europe. RESULTS: The genetic analysis showed a significant, yet relatively weak population structure with high genetic heterozygosity and low inbreeding coefficients, indicating that neutral processes contributed very little to the observed wing shape differences. The genetic analysis also showed that some regions of the genome (about 10%) are putatively shaped by selection. The phylogenetic analysis showed that the Spanish and French populations were the ancestral ones with northern Swedish and Finnish populations being the most derived ones. We found that wing shape differed significantly among populations and showed a significant quadratic (but weak) relationship with latitude. This latitudinal relationship was largely attributed to allometric effects of wing size, but non-allometric variation also explained a portion of this relationship. However, wing shape showed no phylogenetic signal suggesting that lineage-specific variation did not contribute to the variation along the latitudinal gradient. In contrast, wing size, which is correlated with body size in L. sponsa, had a strong negative correlation with latitude. CONCLUSION: Our results suggest a relatively weak population structure among the sampled populations across Europe, but a clear differentiation between south and north populations. The observed geographic phenotypic variation in wing shape may have been affected by different local selection pressures or environmental effects.

Developmental noise and phenotypic plasticity are correlated in Drosophila simulans.

Non-genetic variation is the phenotypic variation induced by the differential expression of a genotype in response to varying environmental cues and is broadly categorized into two types: phenotypic plasticity and developmental noise. These aspects of variation have been suggested to play an important role in adaptive evolution. However, the mechanisms by which these two types of non-genetic variations influence the evolutionary process are currently poorly understood. Using a machine-learning-based phenotyping tool, we independently quantified phenotypic plasticity and developmental noise in the wing morphological traits of the fruit fly Drosophila simulans. Utilizing a rearing experiment, we demonstrated plastic responses in both wing size and shape as well as non-zero heritability of both phenotypic plasticity and developmental noise, which suggests that adaptive phenotypic plasticity can evolve via genetic accommodation in the wing morphology of D. simulans. We found a positive correlation between phenotypic plasticity and developmental noise, while the correlation between the plastic response to three kinds of environmental factors that were examined (nutrient condition, temperature, and light-dark cycle) was poor. These results suggest that phenotypic plasticity and developmental noise contribute to evolvability in a similar manner, however, the mechanisms that underlie the correspondence between these two types of variation remain to be elucidated.