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Urbanization is a major contributor to the loss of biodiversity. Its rapid progress is mostly at the expense of natural ecosystems and the species inhabiting them. While some species can adjust quickly and thrive in cities, many others cannot. To support biodiversity conservation and guide management decisions in urban areas, it is important to find robust methods to estimate the urban affinity of species (i.e. their tendency to live in urban areas) and understand how it is associated with their traits. Since previous studies mainly relied on discrete classifications of species' urban affinity, often involving inconsistent assessments or variable parameters, their results were difficult to compare. To address this issue, we developed and evaluated a set of continuous indices that quantify species' urban affinity based on publicly available occurrence data. We investigated the extent to which a species' position along the urban affinity gradient depends on the chosen index and how this choice affects inferences about the relationship between urban affinity and a set of morphological, sensory and functional traits. While these indices are applicable to a wide range of taxonomic groups, we examined their performance using a global set of 356 bat species. As bats vary in sensitivity to anthropogenic disturbances, they provide an interesting case study. We found that different types of indices resulted in different rankings of species on the urban affinity spectrum, but this had little effect on the association of traits with urban affinity. Our results suggest that bat species predisposed to urban life are characterized by low echolocation call frequencies, relatively long call durations, small body size and flexibility in the selection of the roost type. We conclude that simple indices are appropriate and practical, and propose to apply them to more taxa to improve our understanding of how urbanization favours or filters species with particular traits.
Abstract
While chemical communication has been investigated intensively in vertebrates and insects, relatively little is known about the sensory world of spiders despite the fact that chemical cues play a key role in natural and sexual selection in this group. In insects, olfaction is performed with wall–pore and gustation with tip‐pore sensilla. Since spiders possess tip‐pore sensilla only, it is unclear how they accomplish olfaction. We scrutinized the ultrastructure of the trichoid tip‐pore sensilla of the orb weaving spider Argiope bruennichi—a common Palearctic species the males of which are known to be attracted by female sex pheromone. We also investigated the congener Argiope blanda. We examined whether the tip‐pore sensilla differ in ultrastructure depending on sex and their position on the tarsi of walking legs of which only the distal parts are in contact with the substrate. We hypothesized as yet undetected differences in ultrastructure that suggest gustatory versus olfactory functions. All tarsal tip‐pore sensilla of both species exhibit characters typical of contact‐chemoreceptors, such as (a) the presence of a pore at the tip of the sensillum shaft, (b) 2–22 uniciliated chemoreceptive cells with elongated and unbranched dendrites reaching up to the tip‐pore, (c) two integrated mechanoreceptive cells with short dendrites and large tubular bodies attached to the sensillum shaft's base, and (d) a socket structure with suspension fibres that render the sensillum shaft flexible. The newly found third mechanoreceptive cell attached to the proximal end of the peridendritic shaft cylinder by a small tubular body was likely overlooked in previous studies. The organization of tarsal tip‐pore sensilla did not differ depending on the position on the tarsus nor between the sexes. As no wall‐pore sensilla were detected, we discuss the probability that a single type of sensillum performs both gustation and olfaction in spiders.
Hibernation is a widespread adaptation in animals to seasonally changing environmental conditions. In the face of global anthropogenic change, information about plastic adjustments to environmental conditions and associated mortality costs are urgently needed to assess population persistence of hibernating species. Here, we used a five-year data set of 1047 RFID-tagged individuals from two bat species, Myotis nattereri and Myotis daubentonii that were automatically recorded each time they entered or left a hibernaculum. Because the two species differ in foraging strategy and activity pattern during winter, we expected species–specific responses in the timing of hibernation relative to environmental conditions, as well as different mortality costs of early departure from the hibernaculum in spring. Applying mixed-effects modelling, we disentangled population-level and individual-level plasticity in the timing of departure. To estimate mortality costs of early departure, we used both a capture mark recapture analysis and a novel approach that takes into account individual exposure times to mortality outside the hibernaculum. We found that the timing of departure varied between species as well as among and within individuals, and was plastically adjusted to large-scale weather conditions as measured by the NAO (North Atlantic Oscillation) index. Individuals of M. nattereri, which can exploit milder temperatures for foraging during winter, tuned departure more closely to the NAO index than individuals of M. daubentonii, which do not hunt during winter. Both analytical approaches used to estimate mortality costs showed that early departing individuals were less likely to survive until the subsequent hibernation period than individuals that departed later. Overall, our study demonstrates that individuals of long-lived hibernating bat species have the potential to plastically adjust to changing climatic conditions, although the potential for adjustment differs between species.
Abstract
Pikeperch (Sander lucioperca) has become a species of interest in aquaculture. It is a popular and economically valuable food fish and can produce high numbers of offspring. However, during early development, there are transition phases when high mortality rates concur with growth changes, vital organ transformations and a limited energy budget. Up to now, no study focused on the developmental adaption of muscle tissue in pikeperch, regardless of muscle tissue influencing essential traits such as locomotion and thus the competence to hunt prey and avoid predators. In the present study, therefore, the developmental myogenesis of pikeperch was analysed using specimens from early embryonic to larval development. Myogenic and developmental genes were utilized to gain insights into transcriptomic regulation during these stages by applying a nanofluidic qPCR approach. Result, three phases of myogenic gene expression, during somitogenesis, during the late embryonic development and during the larval development were detected. Increased myostatin expression showed an interim arrest of muscle formation between embryonic and larval myogenesis. Expression patterns of satellite cell gene markers indicated an accumulation of stem cells before myogenesis interruption. The here gained data will help to broaden the knowledge on percid myogenesis and can support pikeperch rearing in aquaculture.
Abstract
Climate change may force organisms to adapt genetically or plastically to new environmental conditions. Invasive species show remarkable potential for rapid adaptation. The ovoviviparous New Zealand mud snail (NZMS), Potamopyrgus antipodarum, has successfully established across Europe with two clonally reproducing mitochondrial lineages since its arrival in the first half of the 19th century. Its remarkable variation in shell morphology was shown to be fitness relevant. We investigated the effects of temperature on shell morphology across 11 populations from Germany and the Iberian Peninsula in a common garden across three temperatures. We analyzed size and shape using geometric morphometrics. For both, we compared reaction norms and estimated heritabilities. For size, the interaction of temperature and haplotype explained about 50% of the total variance. We also observed more genotype by environment interactions indicating a higher degree of population differentiation than in shape. Across the three temperatures, size followed the expectations of the temperature‐size rule, with individuals growing larger in cold environments. Changes in shape may have compensated for changes in size affecting space for brooding embryos. Heritability estimates were relatively high. As indicated by the very low coefficients of variation for clonal repeatability (CVA), they can probably not be compared in absolute terms. However, they showed some sensitivity to temperature, in haplotype t more so than in z, which was only found in Portugal. The low CVA values indicate that genetic variation among European populations is still restricted with a low potential to react to selection. A considerable fraction of the genetic variation was due to differences between the clonal lineages. The NZMS has apparently not been long enough in Europe to accumulate significant genetic variation relevant for morphological adaptation. As temperature is obviously not the sole factor influencing shell morphology, their interaction will probably not be a factor limiting population persistence under a warming climate in Europe.
Abstract
Aim
Species ranges are highly dynamic, shifting in space and time as a result of complex ecological and evolutionary processes. Disentangling the relative contribution of both processes is challenging but of primary importance for forecasting species distributions under climate change. Here, we use the spectacular range expansion (ca. 1000 km poleward shift within 10 years) of the butterfly Pieris mannii to unravel the factors underlying range dynamics, specifically the role of (i) niche evolution (changes in host‐plant preference and acceptance) and (ii) ecological processes (climate change).
Location
Provence‐Alpes‐Côte d’Azur, France; North Rhine‐Westphalia, Rhineland‐Palatinate and Hesse, Germany.
Taxon
Insect and angiosperms.
Methods
We employed a combination of (i) common garden experiments, based on replicated populations from the species’ historical and newly established range and host‐plant species representative for each distribution range, co‐occurrence analyses and (ii) grid‐based correlative species distribution modelling (SDM) using Maxent.
Results
We observed changes in oviposition preference, with females from the newly established populations showing reduced host‐plant specialization and also an overall increased fecundity. These changes in behaviour and life history may have enabled using a broader range of habitats and thus facilitated the recent range expansion. In contrast, our results indicate that the range expansion is unlikely to be directly caused by anthropogenic climate change, as the range was not constrained by climate in the first place.
Main conclusions
We conclude that evolution of a broader dietary niche rather than climate change is associated with the rapid range expansion, and discuss potential indirect consequences of climate change as trigger for the genetic differences found. Our study thus illustrates the importance of species interactions in shaping species distributions and range shifts, and draws attention to indirect effects of climate change. Embracing this complexity is likely the key to a better understanding of range dynamics.
Abstract
Sander lucioperca is an organism of growing importance for the aquaculture industry. Nonetheless, the rearing of S. lucioperca larvae is proving to be a difficult task as it is facing a high mortality rate during hatching and the change to exogenous feeding. To gain insight into growth patterns during this period, the authors analysed pikeperch embryos and larvae from 9 days before hatching to 17 days after hatch. Hereby they were able to describe a natural development by using close to natural conditions based on using a direct flow‐through supply of lake fresh water on specimens from a local wild population. The results show that between the early embryonic stages a steady growth was visible. Nonetheless, in between hatching and the start of exogenous feeding, a phase of growth stagnation took place. In the following larval stages, an increased growth with large size variations between individual specimens appeared. Both factors are conspicuous as they can indicate a starting point for cannibalism. With this analysis, the authors can provide a fundament to support the upcoming research on S. lucioperca and aid to optimize size‐sorting procedures for a higher survival of pikeperch stock in aquaculture.
In mandibulate arthropods, the primary olfactory centers, termed olfactory lobes in crustaceans, are typically organized in distinct fields of dense synaptic neuropils called olfactory glomeruli. In addition to olfactory sensory neuron terminals and their postsynaptic efferents, the glomeruli are innervated by diverse neurochemically distinctive interneurons. The functional morphology of the olfactory glomeruli is understudied in crustaceans compared with insects and even less well understood and described in a particular crustacean subgroup, the Peracarida, which embrace, for example, Amphipoda and Isopoda. Using immunohistochemistry combined with confocal laser scanning microscopy, we analyzed the neurochemistry of the olfactory pathway in the amphipod Parhyale hawaiensis. We localized the biogenic amines serotonin and histamine as well as the neuropeptides RFamide, allatostatin, orcokinin, and SIFamide. As for other classical neurotransmitters, we stained for γ-aminobutyric acid and glutamate decarboxylase and used choline acetyltransferase as indicator for acetylcholine. Our study is another step in understanding principles of olfactory processing in crustaceans and can serve as a basis for understanding evolutionary transformations of crustacean olfactory systems.
Abstract
Improving our sparse knowledge of the mating and reproductive behaviour of white rhinoceros (Ceratotherium simum Burchell, 1817) is essential for the effective conservation of this iconic species. By combining morphological, physiological and habitat data with paternity assignments of 104 known mother–offspring pairs collected over a period of 13 years, we provide the most comprehensive analysis of the mating system in this species. We show that while the overall mating system was promiscuous, and both males and females produced more offspring when mating with several partners, half of all females with multiple offspring were monogamous. Additionally, we find that mating and reproductive success varied significantly among territorial males in two independent sets of males. In females, however, variation in the mating and the reproductive success was not larger than expected by random demographic fluctuations. Horn size, testosterone metabolite concentration, territory size, habitat openness and the volume of preferred food within the territory did not seem to influence male mating or reproductive success. Moreover, there was no sign of inbreeding avoidance: females tended to mate more frequently with closely related males, and one daughter produced a progeny with her father. The lack of inbreeding avoidance, in combination with the skew in male reproductive success, the partial monogamy in females and the territorial‐based mating system, jeopardizes the already low genetic variation in the species. Considering that the majority of populations are restricted to fenced reserves and private farms, we recommend taking preventive measures that aim to reduce inbreeding in white rhinoceros. A video abstract can be viewed here.
Abstract
Background
Several leech species of the genera Hirudo, Hirudinaria, and Whitmania are widely used in traditional Chinese medicine (TCM) for the oral treatment of disorders associated with blood stasis. Among them, the non‐hematophagous leech Whitmania pigra expresses a variety of components that have the potential to act on the vertebrate blood coagulation system.
Objective
Whether the thrombin inhibitor hirudin, probably the most prominent leech‐derived anticoagulant, is actually present in Whitmania pigra, is still a matter of debate. To answer that open question was the aim of the study.
Methods
We identified several putative hirudin‐encoding sequences in transcriptome data of Whitmania pigra. Upon gene synthesis and molecular cloning the respective recombinant proteins were expressed in Escherichia coli, purified, processed, and eventually functionally characterized for thrombin‐inhibitory potencies in coagulation assays.
Results
We were successful in the identification and functional characterization of several putative hirudins in Whitmania pigra. Some, but not all, of these factors are indeed thrombin inhibitors. Whitmania pigra hence expresses both hirudins (factors that inhibit thrombin) and hirudin‐like factors (that do not or only very weakly inhibit thrombin). Furthermore, we revealed the exon/intron structures of the corresponding genes. Coding sequences of some putative hirudins of Whitmania pigra were present also in transcriptome datasets of Hirudo nipponia, a hematophagous leech that is likewise used in TCM.
Conclusions
Based on both structural and functional data we provide very strong evidence for the expression of hirudins in Whitmania pigra. This is the first description of hirudins in a non‐hematophagous leech.
How organisms that are part of the same trophic network respond to environmental variability over small spatial scales has been studied in a multitude of systems. Prevailing theory suggests a large role for plasticity in key traits among interacting species that allows matching of life cycles or life‐history traits across environmental gradients, for instance insects tracking host‐plant phenology across variable environments (Posledovich et al. 2018). A key aspect that remains understudied is the extent of intrapopulation variability in plasticity and whether stressful conditions canalize plasticity to an optimal level, or alternatively if variation in plasticity indeed could increase fitness in itself via alternative strategies. In a From the Cover article in this issue of Molecular Ecology, Kahilainen et al. (2022) investigate this issue in a classical insect study system, the metapopulation of the Glanville fritillary butterfly (Melitea cinxia) in the Åland archipelago of Finland. The authors first establish how a key host plant responds to water limitation, then quantify among‐family variation in larval growth and development across control and water‐limited host plants. Finally, they use RNA sequencing to gain mechanistic insights into some of these among‐family differences in larval performance in response to host‐plant variation, finding results suggesting the existence of heritable, intrapopulation variability in ecologically relevant plasticity. This final step represents a critically important and often overlooked component of efforts to predict sensitivity of biological systems to changing environmental conditions, since it provides a key metric of adaptive resilience present in the system.
Abstract
Nervous system development has been intensely studied in insects (especially Drosophila melanogaster), providing detailed insights into the genetic regulatory network governing the formation and maintenance of the neural stem cells (neuroblasts) and the differentiation of their progeny. Despite notable advances over the last two decades, neurogenesis in other arthropod groups remains by comparison less well understood, hampering finer resolution of evolutionary cell type transformations and changes in the genetic regulatory network in some branches of the arthropod tree of life. Although the neurogenic cellular machinery in malacostracan crustaceans is well described morphologically, its genetic molecular characterization is pending. To address this, we established an in situ hybridization protocol for the crayfish Procambarus virginalis and studied embryonic expression patterns of a suite of key genes, encompassing three SoxB group transcription factors, two achaete–scute homologs, a Snail family member, the differentiation determinants Prospero and Brain tumor, and the neuron marker Elav. We document cell type expression patterns with notable similarities to insects and branchiopod crustaceans, lending further support to the homology of hexapod–crustacean neuroblasts and their cell lineages. Remarkably, in the crayfish head region, cell emigration from the neuroectoderm coupled with gene expression data points to a neuroblast‐independent initial phase of brain neurogenesis. Further, SoxB group expression patterns suggest an involvement of Dichaete in segmentation, in concordance with insects. Our target gene set is a promising starting point for further embryonic studies, as well as for the molecular genetic characterization of subregions and cell types in the neurogenic systems in the adult crayfish brain.
Animals face strong environmental variability even on short time scales particularly in shallow coastal habitats, forcing them to permanently adjust their metabolism. Respiration rates of aquatic ectotherms are directly influenced by water temperature, whereas ingestion rates might additionally be influenced by behavior. We aim to understand how respiration and ingestion rates of an aquatic invertebrate respond to changing temperature during a diurnal thermal fluctuation cycle and how both processes are related. We studied the benthopelagic mysid Neomysis integer as an important food web component of coastal ecosystems. Mysids were collected at the southern Baltic Sea coast and exposed in the laboratory to either constant temperature of 15°C or daily temperature fluctuation of 15 ± 5°C. Short-term (1–2 h) respiration and ingestion rates were measured at four equidistant time points within 24 h and did not differ among time points at constant temperature, but differed among time points in the fluctuating treatment. Respiration was highest at the thermal maximum and lowest at the thermal minimum. Ingestion rates showed the opposite pattern under fluctuation, likely due to differences in underlying thermal performance curves. When temperature transited the average, the direction of temperature change influenced the animals' response in respiration and ingestion rates differently. Our results suggest that respiration is not only instantaneously affected by temperature, but also influenced by the previously experienced direction of thermal change. Our experiment, using an important non-model organism, delivered new insights on the relationship between the crucial organismal processes ingestion and respiration under thermal variability.
Currently, poleward range expansions are observed in many taxa, often in response to anthropogenic climate change. At the expanding front, populations likely face cooler and more variable temperature conditions, imposing thermal selection. This may result in changes in trait means or plasticity, the relative contribution of which is not well understood. We, here, investigate evolutionary change in range‐expanding populations of the butterfly Pieris mannii, by comparing populations from the core and the newly established northern range under laboratory conditions. We observed both changes in trait means and in thermal reaction norms. Range‐expanding populations showed a more rapid development, potentially indicative of counter‐gradient variation and an increased cold tolerance compared with core populations. Genotype‐environment interactions prevailed in all associated traits, such that the above differences were restricted to cooler environmental conditions. In range‐expanding populations, plasticity was decreased in developmental traits enabling relatively rapid growth even under cooler conditions but increased in cold tolerance arguably promoting higher activity under thermally challenging conditions. Notably, these changes must have occurred within a time period of ca. 10 years only. Our results suggest, in line with contemporary theory, that the evolution of plasticity may play a hitherto underestimated role for adaptation to climatic variation. However, rather than generally increased or decreased levels of plasticity, our results indicate fine‐tuned, trait‐specific evolutionary responses to increase fitness in novel environments.
Extra-organismal DNA (eoDNA) from material left behind by organisms (noninvasive DNA, e.g., feces, hair) or from environmental samples (eDNA, e.g., water, soil) is a valuable source of genetic information. However, the relatively low quality and quantity of eoDNA, which can be further degraded by environmental factors, results in reduced amplification and sequencing success. This is often compensated for through cost- and time-intensive replications of genotyping/sequencing procedures. Therefore, system- and site-specific quantifications of environmental degradation are needed to maximize sampling efficiency (e.g., fewer replicates, shorter sampling durations), and to improve species detection and abundance estimates. Using 10 environmentally diverse bat roosts as a case study, we developed a robust modeling pipeline to quantify the environmental factors degrading eoDNA, predict eoDNA quality, and estimate sampling-site-specific ideal exposure duration. Maximum humidity was the strongest eoDNA-degrading factor, followed by exposure duration and then maximum temperature. We also found a positive effect when hottest days occurred later. The strength of this effect fell between the strength of the effects of exposure duration and maximum temperature. With those predictors and information on sampling period (before or after offspring were born), we reliably predicted mean eoDNA quality per sampling visit at new sites with a mean squared error of 0.0349. Site-specific simulations revealed that reducing exposure duration to 2–8 days could substantially improve eoDNA quality for future sampling. Our pipeline identified high humidity and temperature as strong drivers of eoDNA degradation even in the absence of rain and direct sunlight. Furthermore, we outline the pipeline's utility for other systems and study goals, such as estimating sample age, improving eDNA-based species detection, and increasing the accuracy of abundance estimates.
Primary producer communities are often growth-limited by essential nutrients such as nitrogen (N) and phosphorus (P). The magnitude of limitation and whether N, P or both elements are limiting autotroph growth depends on the supply and ratios of these essential nutrients. Previous studies identified single, serial or co-limitation as predominant limitation outcomes in autotroph communities by factorial nutrient additions. Little is known about potential consequences of such scenarios for herbivores and whether their growth is primarily affected by changes in autotroph quantity or nutritional quality. We grew a community of phytoplankton species differing in various food quality aspects in experimental microcosms at varying N and P concentrations resulting in three different N:P ratios. At carrying capacity, N, P, both nutrients or none were added to reveal which nutrients were limiting. The nutrient-supplied communities were fed to the generalist herbivorous rotifer Brachionus calyciflorus to investigate how changing phytoplankton biomass and community composition affect herbivore abundance. We found phytoplankton being growth-limited either by N alone (single limitation) or serially, i.e. primarily by N and secondarily by P, altering available food quantity for rotifers. Rotifer growth showed a different response pattern compared to phytoplankton, suggesting that apart from food quantity food quality aspects played a substantial role in the transfer from primary to secondary production. The combined addition of N and P to phytoplankton had generally a positive effect on herbivore growth, whereas adding non-limiting nutrients had a rather detrimental effect probably due to stoichiometrically imbalanced food in terms of nutrient excess. Our experiment shows that adding various nutrients to primary producer communities will not always lead to increased autotroph and herbivore growth, and that differences between autotroph and herbivore responses under co-limiting conditions can be partly well explained by concepts of ecological stoichiometry theory.
1. Anthropogenic climate change is a substantial threat to global biodiversity. It may affect insect herbivores directly and indirectly. Indirect effects are, among others, mediated by climate‐change induced variation in host‐plant quality. Although being potentially important, little is known on the significance of such indirect effects and on interactions among environmental stressors in plant–herbivore interactions.
2. To simulate the potential impact of climate change, we investigated effects of host‐plant temperature and soil moisture on herbivore performance in the tropical butterfly Bicyclus anynana under laboratory conditions.
3. Maize grown at high temperatures or under wet conditions reduced herbivore performance, indicated by decreased body mass, storage reserves, phenoloxidase activity, and increased development time. Temperature and soil moisture acted largely independent of one another. Detrimental effects of the high plant temperature were restricted to males, indicating a higher vulnerability of this sex to environmental stress.
4. In nature, B. anynana might be threatened by increasing temperatures during the wet season negatively affecting host‐plant quality. Our study shows that herbivore performance can be substantially affected by indirect effects mediated through changes in host‐plant quality, which deserves more attention in the current era of global climate change.
How well populations can cope with global warming will often depend on the evolutionary potential and plasticity of their temperature-sensitive, fitness-relevant traits. In Bechstein's bats (Myotis bechsteinii), body size has increased over the last decades in response to warmer summers. If this trend continues it may threaten populations as larger females exhibit higher mortality. To assess the evolutionary potential of body size, we applied a Bayesian ‘animal model’ to estimate additive genetic variance, heritability and evolvability of body size, based on a 25-year pedigree of 332 wild females. Both heritability and additive genetic variance were reduced in hot summers compared to average and cold summers, while evolvability of body size was generally low. This suggests that the observed increase in body size was mostly driven by phenotypic plasticity. Thus, if warm summers continue to become more frequent, body size likely increases further and the resulting fitness loss could threaten populations.
Geometric regularity of spider webs has been intensively studied in orb‐weaving spiders, although it is not exclusive of orb weavers. Here, we document the geometrically regular, repetitive elements in the webs of the non‐orb‐weaving groups Leptonetidae and Telemidae for the first time. Similar to orb weavers, we found areas with regularly spaced parallel lines in the webs of Calileptoneta helferi, Sulcia sp., and cf. Pinelema sp. Furthermore, we provide a detailed account of the regular webs of Ochyrocera (Ochyroceratidae). The sections of the web with regularly disposed parallel lines are built as U‐shaped modules reminiscent of orb webs. It has been suggested that the regularly spaced parallel lines in the webs of Ochyroceratidae and Psilodercidae may be produced in a single sweep of their posterior lateral spinnerets, which have regularly spaced aciniform gland spigots, perhaps involving expansion of the spinnerets. To test this hypothesis, we compared the spacing between parallel lines with the spacing between spigots, searched for expansible membranes in the spinnerets, and examined the junctions of regularly spaced lines. The distance between parallel lines was 10–20 times the distance between spigots, and we found no expansible membranes, and the intersection of parallel lines are cemented, which opposes the single sweep hypothesis. Furthermore, we found cues of viscid silk in the parallel lines of the psilodercid Althepus and broadened piriform gland spigots that may be responsible of its production. Finally, we evaluated the presence or absence of geometrically regular web elements across the spider tree of life. We found reports of regular webs in 31 spider families, including 20 families that are not orb weavers and hypothesize that the two basic aspects of regularity (parallel lines spaced at regular intervals, and radial lines spaced at regular angles) probably appeared many times in the evolution of spiders.
Abstract
Understanding how organisms adapt to complex environments is a central goal of evolutionary biology and ecology. This issue is of special interest in the current era of rapidly changing climatic conditions. Here, we investigate clinal variation and plastic responses in life history, morphology and physiology in the butterfly Pieris napi along a pan‐European gradient by exposing butterflies raised in captivity to different temperatures. We found clinal variation in body size, growth rates and concomitant development time, wing aspect ratio, wing melanization and heat tolerance. Individuals from warmer environments were more heat‐tolerant and had less melanised wings and a shorter development, but still they were larger than individuals from cooler environments. These findings suggest selection for rapid growth in the warmth and for wing melanization in the cold, and thus fine‐tuned genetic adaptation to local climates. Irrespective of the origin of butterflies, the effects of higher developmental temperature were largely as expected, speeding up development; reducing body size, potential metabolic activity and wing melanization; while increasing heat tolerance. At least in part, these patterns likely reflect adaptive phenotypic plasticity. In summary, our study revealed pronounced plastic and genetic responses, which may indicate high adaptive capacities in our study organism. Whether this may help such species, though, to deal with current climate change needs further investigation, as clinal patterns have typically evolved over long periods.