Evolved changes in phenotype across skeletal muscles in deer mice native to high altitude.

The cold and hypoxic conditions at high altitude necessitate high metabolic O2 demands to support thermogenesis while hypoxia reduces O2 availability. Skeletal muscles play key roles in thermogenesis, but our appreciation of muscle plasticity and adaptation at high altitude has been hindered by past emphasis on only a small number of muscles. We examined this issue in deer mice (Peromyscus maniculatus). Mice derived from both high-altitude and low-altitude populations were born and raised in captivity and then acclimated as adults to normoxia or hypobaric hypoxia (12 kPa O2 for 6-8 wk). Maximal activities of citrate synthase (CS), cytochrome c oxidase (COX), ß-hydroxyacyl-CoA dehydrogenase (HOAD), hexokinase (HK), pyruvate kinase (PK), and lactate dehydrogenase (LDH) were measured in 20 muscles involved in shivering, locomotion, body posture, ventilation, and mastication. Principal components analysis revealed an overall difference in muscle phenotype between populations but no effect of hypoxia acclimation. High-altitude mice had greater activities of mitochondrial enzymes and/or lower activities of PK or LDH across many (but not all) respiratory, limb, core and mastication muscles compared with low-altitude mice. In contrast, chronic hypoxia had very few effects across muscles. Further examination of CS in the gastrocnemius showed that population differences in enzyme activity stemmed from differences in protein abundance and mRNA expression but not from population differences in CS amino acid sequence. Overall, our results suggest that evolved increases in oxidative capacity across many skeletal muscles, at least partially driven by differences in transcriptional regulation, may contribute to high-altitude adaptation in deer mice.NEW & NOTEWORTHY Most previous studies of muscle plasticity and adaptation in high-altitude environments have focused on a very limited number of skeletal muscles. Comparing high-altitude versus low-altitude populations of deer mice, we show that a large number of muscles involved in shivering, locomotion, body posture, ventilation, and mastication exhibit greater mitochondrial enzyme activities in the high-altitude population. Therefore, evolved increases in mitochondrial oxidative capacity across skeletal muscles contribute to high-altitude adaptation.

The adaptation of bumblebees to extremely high elevation associated with their gut microbiota.

Bumblebees are among the most abundant and important pollinators for sub-alpine and alpine flowering plant species in the Northern Hemisphere, but little is known about their adaptations to high elevations. In this article, we focused on two bumblebee species, Bombus friseanus and Bombus prshewalskyi, and their respective gut microbiota. The two species, distributed through the Hengduan Mountains of southwestern China, show species replacement at different elevations. We performed genome sequencing based on 20 worker bee samples of each species. Applying evolutionary population genetics and metagenomic approaches, we detected genes under selection and analyzed functional pathways between bumblebees and their gut microbes. We found clear genetic differentiation between the two host species and significant differences in their microbiota. Species replacement occurred in both hosts and their bacteria (Snodgrassella) with an increase in elevation. These extremely high-elevation bumblebees show evidence of positive selection related to diverse biological processes. Positively selected genes involved in host immune systems probably contributed to gut microbiota changes, while the butyrate generated by gut microbiota may influence both host energy metabolism and immune systems. This suggests a close association between the genomes of the host species and their microbiomes based on some degree of natural selection.IMPORTANCETwo closely related and dominant bumblebee species, distributed at different elevations through the Hengduan Mountains of southwestern China, showed a clear genomic signature of adaptation to elevation at the molecular level and significant differences in their respective microbiota. Species replacement occurred in both hosts and their bacteria (Snodgrassella) with an increase in elevation. Bumblebees' adaptations to higher elevations are closely associated with their gut microbiota through two biological processes: energy metabolism and immune response. Information allowing us to understand the adaptive mechanisms of species to extreme conditions is implicit if we are to conserve them as their environments change.

Elevational variation in metabolic rate, feeding capacity and their associations in the Asiatic toad Bufo gargarizans.

Foraging behavior is known to place demands on the metabolic characteristics of anurans. Active foragers feeding on sedentary prey typically have high aerobic capacity and low anaerobic capacity, whereas sit-and-wait foragers feeding on active and mobile prey have the opposite pattern. Thus, the energetic demands of foraging may influence their metabolic adaptations to harsh environments, such as high elevations. Anurans that engage in active foraging have been found to increase maximum metabolic rate (MMR) and aerobic scope (AS, the difference between MMR and resting metabolic rate, RMR) at high elevations. However, data are lacking in amphibian ambush foragers. In this study, we examined the RMR, MMR, AS, and feeding capacity of a sit-and-wait forager ─the Asiatic toad (Bufo gargarizans), from two populations that are in close geographic proximity but differ by 1350 m in elevation. Our results show that there is no elevational variation in RMR and feeding capacity in either males or females. However, there are sex-specific variations in MMR and AS along an elevational gradient; females from high elevations have lower MMR and smaller net AS than their counterparts from low elevations while males maintain similar MMR and net AS across elevations. Furthermore, aerobic performances do not appear to be associated with feeding capacity at either the individual or population level. Our results support the hypothesis that sit-and-wait foragers may not increase their aerobic capacity as a strategy in hypoxic and low food availability environments and the role of sex in these adaptive adjustments should not be overlooked.

Taxonomic Reinstatement of the Endemic Chinese Species Iris thoroldii (Iridaceae) from I. potaninii and Reassessment of I. zhaoana.

Iris thoroldii is a perennial herbaceous plant with yellow, blue, or purple flowers. The species is native to the Tibetan Plateau and adjacent areas. In the literature and databases, I. thoroldii has long been treated in synonymy with I. potaninii. Currently, yellow-flowered plants of I. thoroldii are considered I. potanii, and blue-flowered plants are considered I. zhaoana, a replacement name for I. potaninii var. ionantha. This study aimed to clarify the taxonomic identity of I. thoroldii. A critical examination of original material, herbarium specimens, images of living plants, and the literature has shown I. thoroldii to be different from I. potaninii in some previously neglected macromorphological traits and to be conspecific with I. zhaoana. Thus, I. thoroldii is removed here from the synonymy of I. potaninii and accepted as a distinct species. This is endemic to China (central Gansu, Qinghai, and northwestern Sichuan provinces, and also Xinjiang Uygur and Tibet autonomous regions) and reaches the highest elevations compared with all other species in the genus Iris s.l. A revised taxonomy of I. thoroldii is provided, and two color forms, often co-occurring, are accepted: the autonymic yellow-flowered form (including a new synonym I. tigridia var. flavescens for which a lectotype was designated) and a form with blue or purple colors is proposed here, I. thoroldii f. ionantha. In addition, images of type specimens and detailed photographs of living plants for easy identification, along with the list of specimens of I. thoroldii that were examined, and also, comments on its distribution and habitats are provided.

Changes in air temperature, but not in precipitation, determine long-term trends in water chemistry of high mountain lakes of the Alps with and without rock glacier influence.

Climate change has strongly affected lakes around the world, but the relative effects of warmer air temperatures and changing precipitation on the water chemistry of alpine systems are not well understood. Here we tested the effect of monthly and seasonal climate on the water chemistry of six high mountain lakes located in the Alps. From 1982 to 2020, water samples were collected annually from different depths during the autumn mixing. We observed a simultaneous increase in electrical conductivity, ionic content, and pH with air temperature. In lakes with rock glacier influence, the increase in conductivity, ionic content, and especially in sulfate was even more pronounced, but accompanied by a strong decrease in pH. These differences are attributed to the direct influence of acidic meltwater from active rock glaciers in catchments with acidic bedrock. We then analyzed changes in lake chemistry, taking into account seasonal trends in air temperature and precipitation, using redundancy analysis. Temperature increase significantly affected water chemistry in five of the six lakes, especially at times of ice breakup. Increasing warming explained 17% to 32% of the changes in electrical conductivity, alkalinity, pH, major ions, and nitrogen. In contrast, precipitation had little effect on the changes of those parameters. Nevertheless, late spring snowfall and high snowfall in early fall, which result in prolonged ice cover, had a dampening effect on the impact of climate warming on lake chemistry. Our results confirm that climate warming remains a major driver of chemical changes in alpine lakes, but provide new evidence that late spring temperatures are the most important triggers.

Embryonic and juvenile snakes (Natrix maura, Linnaeus 1758) compensate for high elevation hypoxia via shifts in cardiovascular physiology and metabolism.

The colonization of novel environments requires a favorable response to conditions never, or rarely, encountered in recent evolutionary history. For example, populations colonizing upslope habitats must cope with lower atmospheric pressure at elevation, and thus reduced oxygen availability. The embryo stage in oviparous organisms is particularly susceptible, given its lack of mobility and limited gas exchange via diffusion through the eggshell and membranes. Especially little is known about responses of Lepidosaurian reptiles to reduced oxygen availability. To test the role of physiological plasticity during early development in response to high elevation hypoxia, we performed a transplant experiment with the viperine snake (Natrix maura, Linnaeus 1758). We maintained gravid females originating from low elevation populations (432 m above sea level [ASL]-normoxia) at both the elevation of origin and high elevation (2877 m ASL-extreme high elevation hypoxia; approximately 72% oxygen availability relative to sea level), then incubated egg clutches at both low and high elevation. Regardless of maternal exposure to hypoxia during gestation, embryos incubated at extreme high elevation exhibited altered developmental trajectories of cardiovascular function and metabolism across the incubation period, including a reduction in late-development egg mass. This physiological response may have contributed to the maintenance of similar incubation duration, hatching success, and hatchling body size compared to embryos incubated at low elevation. Nevertheless, after being maintained in hypoxia, juveniles exhibit reduced carbon dioxide production relative to oxygen consumption, suggesting altered energy pathways compared to juveniles maintained in normoxia. These findings highlight the role of physiological plasticity in maintaining rates of survival and fitness-relevant phenotypes in novel environments.

Concepts in Alpine Plant Ecology.

The alpine life zone is perhaps the only biome that occurs globally where mountains are high enough. At latitudinally varying elevation, the alpine belt hosts small stature plants that vary greatly in morphology, anatomy and physiology. In this contribution, I summarize a number of principles that govern life in what is often considered a cold and hostile environment. The 12 conceptual frameworks depicted include the key role of aerodynamic decoupling from free atmospheric climatic conditions, the problematic concepts of limitation and stress in an evolutionary context, and the role of developmental flexibility and functional diversity. With its topography driven habitat diversity, alpine plant diversity is buffered against environmental change, and the multitude of microclimatic gradients offers 'experiments by nature', the power of which awaits multidisciplinary exploration.

Global change may make hostile - Higher ambient temperature and nitrogen availability increase ant aggression.

Behaviour is a response of organisms to internal and external stimuli and comprises various activities such as searching for food. Aggression is important in such activities, for example, improving the chances of winning competition for food, but animals differ in their level of aggression. This behavioural plasticity allows individuals to respond to environmental changes and is important for the survival of animals. It may be an important asset in facing global changes, which affect all organisms, for example, via rising temperature and eutrophication. The latter have steadily increased since 1900, especially in high elevations. Their effects may first become visible in stationary organisms such as ants because their nests are strictly associated with the conditions on site. Here, we analysed eight populations of the high-elevation ant Tetramorium alpestre along several elevations spanning the European Alps. We conducted a correlative approach and analysed several genetic and environmental proxies, namely within- and across-colony genetic relatedness, cuticular hydrocarbons, body size, across-colony geographic distance, air temperature, and worker nitrogen values additionally to within-population aggressive behaviour. We hypothesised that a) these proxies and aggressive behaviour differ among populations and that b) one or more of these proxies influence aggression. We found that a) some environmental proxies and aggression differed among populations but not the genetic proxies and that b) air temperature and worker nitrogen-isotope values correlated positively with worker aggression. The results indicate an environmental but not social-structural influence on this ant's aggressive behaviour, even though social structure varied among populations (single- and multiple-queened colonies). We infer that global change affects aggression in our study system and propose five mutually non-exclusive scenarios to explain the behavioural change mechanistically. Using the space-for-time principle, we speculate that aggression may increase due to future increases in temperature and nitrogen availability in this ant and other species living in high elevations.

A stochastic cellular automaton model to describe the evolution of the snow-covered area across a high-elevation mountain catchment.

Variations in the extent and duration of snow cover impinge on surface albedo and snowmelt rate, influencing the energy and water budgets. Monitoring snow coverage is therefore crucial for both optimising the supply of snowpack-derived water and understanding how climate change could impact on this source, vital for sustaining human activities and the natural environment during the dry season. Mountainous sites can be characterised by complex morphologies, cloud cover and forests that can introduce errors into the estimates of snow cover obtained from remote sensing. Consequently, there is a need to develop simulation models capable of predicting how snow coverage evolves across a season. Cellular Automata models have previously been used to simulate snowmelt dynamics, but at a coarser scale that limits insight into the precise factors driving snowmelt at different stages. To address this information gap, we formulate a novel, fine-scale stochastic Cellular Automaton model that describes snow coverage across a high-elevation catchment. Exploiting its refinement, the model is used to explore the interplay between three factors proposed to play a critical role: terrain elevation, sun incidence angle, and the extent of nearby snow. We calibrate the model via a randomised parameter search, fitting simulation data against snow cover masks estimated from Sentinel-2 satellite images. Our analysis shows that.

Comparative Analysis of Chloroplast Genomes within Saxifraga (Saxifragaceae) Takes Insights into Their Genomic Evolution and Adaption to the High-Elevation Environment.

Saxifraga species are widely distributed in alpine and arctic regions in the Northern hemisphere. Highly morphological diversity within this genus brings great difficulties for species identification, and their typical highland living properties make it interesting how they adapt to the extreme environment. Here, we newly generated the chloroplast (cp) genomes of two Saxifraga species and compared them with another five Saxifraga cp genomes to understand the characteristics of cp genomes and their potential roles in highland adaptation. The genome size, structure, gene content, GC content, and codon usage pattern were found to be highly similar. Cp genomes ranged from 146,549 bp to 151,066 bp in length, most of which comprised 130 predicted genes. Yet, due to the expansion of IR regions, the second copy of rps19 in Saxifraga stolonifera was uniquely kept. Through sequence divergence analysis, we identified seven hypervariable regions and detected some signatures of regularity associated with genetic distance. We also identified 52 to 89 SSRs and some long repeats among seven Saxifraga species. Both ML and BI phylogenetic analyses confirmed that seven Saxifraga species formed a monophyletic clade in the Saxifragaceae family, and their intragenus relationship was also well supported. Additionally, the ndhI and ycf1 genes were considered under positive selection in species inhabiting relatively high altitudes. Given the conditions of intense light and low CO2 concentration in the highland, the products of these two genes might participate in the adaptation to the extreme environment.

Reproduction and genetic diversity of Juniperus squamata along an elevational gradient in the Hengduan Mountains.

Elevation plays a crucial factor in the distribution of plants, as environmental conditions become increasingly harsh at higher elevations. Previous studies have mainly focused on the effects of large-scale elevational gradients on plants, with little attention on the impact of smaller-scale gradients. In this study we used 14 microsatellite loci to survey the genetic structure of 332 Juniperus squamata plants along elevation gradient from two sites in the Hengduan Mountains. We found that the genetic structure (single, clonal, mosaic) of J. squamata shrubs is affected by differences in elevational gradients of only 150 m. Shrubs in the mid-elevation plots rarely have a clonal or mosaic structure compared to shrubs in lower- or higher-elevation plots. Human activity can significantly affect genetic structure, as well as reproductive strategy and genetic diversity. Sub-populations at mid-elevations had the highest yield of seed cones, lower levels of asexual reproduction and higher levels of genetic diversity. This may be due to the trade-off between elevational stress and anthropogenic disturbance at mid-elevation since there is greater elevational stress at higher-elevations and greater intensity of anthropogenic disturbance at lower-elevations. Our findings provide new insights into the finer scale genetic structure of alpine shrubs, which may improve the conservation and management of shrublands, a major vegetation type on the Hengduan Mountains and the Qinghai-Tibet Plateau.

A montane species treeline is defined by both temperature and drought effects on growth season length.

Montane treelines are defined by a threshold low temperature. However, what are the dynamics when the snow-free summer growth season coincides with a 6-month seasonal drought? We tested this fundamental question by measuring tree growth and leaf activity across elevations in Mt Hermon (2814 m; in Israel and Syria), where oak trees (Quercus look and Quercus boissieri) form an observed treeline at 1900 m. While in theory, individuals can be established at higher elevations (minimum daily temperature >6.5 °C for >4 months even at the summit), soil drying and vapor pressure deficit in summer enforces growth cessation in August, leaving only 2-3 months for tree growth. At lower elevations, Q. look Kotschy is replaced by Quercus cerris L. (1300 m) and Quercus calliprinos Webb (1000 m) in accompanying Q. boissieri Reut., and growth season length (GSL) is longer due to an earlier start in April. Leaf gas exchange continues during autumn, but assimilates are no longer utilized in growth. Interestingly, the growth and activity of Q. boissieri were equivalent to that of each of the other three species across the ~1 km elevation gradient. A planting experiment at 2100 m showed that seedlings of the four oak species survived the cold winter and showed budding of leaves in summer, but wilted in August. Our unique mountain site in the Eastern Mediterranean introduces a new factor to the formation of treelines, involving a drought limitation on GSL. This site presents the elevation edge for each species and the southern distribution edge for both the endemic Q. look and the broad-range Q. cerris. With ongoing warming, Q. look and Q. boissieri are slowly expanding to higher elevations, while Q. cerris is at risk of future extirpation.

Biogeographic Patterns and Elevational Differentiation of Sedimentary Bacterial Communities across River Systems in China.

Bacterial biodiversity is tightly correlated with ecological functions of natural systems, and bacterial rare and abundant subcommunities make distinct contributions to ecosystem functioning. However, the biogeographic pattern and elevational differentiation of sedimentary bacterial diversity have rarely been studied in cross-river systems at a continental scale. This study analyzed the biogeographic patterns and elevational differentiations of the entire, abundant, and rare bacterial (sub)communities as well as the underlying mechanisms across nine rivers that span distinct geographic regions and large elevational gradients in China. We found that bacterial rare and abundant subcommunities shared similar biogeographic patterns and both demonstrated strong distance-decay relationships, despite their distinct community compositions. However, both null model and variation partitioning analysis results showed that while environmental selection governed rare subcommunity assemblies (contribution: 51.9%), dispersal limitation (62.7%) controlled the assembly of abundant subcommunities. The disparity was associated with the broader threshold width of abundant taxa to water temperature and pH variations than rare taxa. Elevation-induced bacterial composition variations were more evident than latitude-induced ones. Some specific operational taxonomic units (OTUs), representing 16.4% of the total sequences, much preferentially and even exclusively lived in high-elevation or low-elevation habitats and demonstrated some adaptations to local conditions. Greater positive: negative link ratios in bacterial co-occurrence networks of low elevations than high elevations (P < 0.05) partly resulted from their harboring higher organic carbon: nitrogen ratios. Together, this study draws a biogeographic picture of sedimentary bacterial communities in a continental-scale riverine system and highlights the importance of incorporating elevation-associated patterns of microbial diversity into riverine microbial ecology studies. IMPORTANCE Bacterial diversity is tightly correlated with the nutrient cycling of river systems. However, previous studies on bacterial diversity are mainly constrained to one single river system, although microbial biogeography and its drivers exhibit strong spatial scale dependence. Moreover, elevational differentiations of bacterial communities across river systems have also rarely been studied. Bacterial rare and abundant subcommunities make distinct contributions to ecosystem functioning, and they share similar biogeographic patterns in some environments but not in others. Therefore, we explored the biogeography of the entire, abundant, and rare (sub)communities in nine rivers that cover a wide space range and large elevational gradient in China. Our results revealed that bacterial rare and abundant subcommunities shared similar biogeographic patterns but their assembly mechanisms were much different in these rivers. Moreover, bacterial communities showed evident differentiations between high elevations and low elevations. These findings will facilitate a better understanding of bacterial diversity features in river systems.

The genomic basis of high-elevation adaptation in wild house mice (Mus musculus domesticus) from South America.

Understanding the genetic basis of environmental adaptation in natural populations is a central goal in evolutionary biology. The conditions at high elevation, particularly the low oxygen available in the ambient air, impose a significant and chronic environmental challenge to metabolically active animals with lowland ancestry. To understand the process of adaptation to these novel conditions and to assess the repeatability of evolution over short timescales, we examined the signature of selection from complete exome sequences of house mice (Mus musculus domesticus) sampled across two elevational transects in the Andes of South America. Using phylogenetic analysis, we show that house mice colonized high elevations independently in Ecuador and Bolivia. Overall, we found distinct responses to selection in each transect and largely nonoverlapping sets of candidate genes, consistent with the complex nature of traits that underlie adaptation to low oxygen availability (hypoxia) in other species. Nonetheless, we also identified a small subset of the genome that appears to be under parallel selection at the gene and SNP levels. In particular, three genes (Col22a1, Fgf14, and srGAP1) bore strong signatures of selection in both transects. Finally, we observed several patterns that were common to both transects, including an excess of derived alleles at high elevation, and a number of hypoxia-associated genes exhibiting a threshold effect, with a large allele frequency change only at the highest elevations. This threshold effect suggests that selection pressures may increase disproportionately at high elevations in mammals, consistent with observations of some high-elevation diseases in humans.

Parallel genomic responses to historical climate change and high elevation in East Asian songbirds.

Parallel evolution can be expected among closely related taxa exposed to similar selective pressures. However, parallelism is typically stronger at the phenotypic level, while genetic solutions to achieve these phenotypic similarities may differ. For polygenic traits, the availability of standing genetic variation (i.e., heterozygosity) may influence such genetic nonparallelism. Here, we examine the extent to which high-elevation adaptation is parallel-and whether the level of parallelism is affected by heterozygosity-by analyzing genomes of 19 Paridae species distributed across East Asia with a dramatic east-west elevation gradient. We find that western highlands endemic parids have consistently lower levels of heterozygosity-likely the result of late-Pleistocene demographic contraction-than do parids found exclusively in eastern lowlands, which remained unglaciated during the late Pleistocene. Three widespread species (east to west) have high levels of heterozygosity similar to that observed in eastern species, although their western populations are less variable than eastern ones. Comparing genomic responses to extreme environments of the Qinghai-Tibet Plateau, we find that the most differentiated genomic regions between each high-elevation taxon and its low-elevation relative are significantly enriched for genes potentially related to the oxygen transport cascade and/or thermogenesis. Despite no parallelism at particular genes, high similarity in gene function is found among comparisons. Furthermore, parallelism is not higher in more heterozygous widespread parids than in highland endemics. Thus, in East Asian parids, parallel functional response to extreme elevation appears to rely on different genes, with differences in heterozygosity having no effect on the degree of genetic parallelism.

Disentangling direct and indirect effects of local temperature on abundance of mountain birds and implications for understanding global change impacts.

Unravelling the environmental factors driving species distribution and abundance is crucial in ecology and conservation. Both climatic and land cover factors are often used to describe species distribution/abundance, but their interrelations have been scarcely investigated. Climatic factors may indeed affect species both directly and indirectly, e.g., by influencing vegetation structure and composition. We aimed to disentangle the direct and indirect effects (via vegetation) of local temperature on bird abundance across a wide elevational gradient in the European Alps, ranging from montane forests to high-elevation open areas. In 2018, we surveyed birds by using point counts and collected fine-scale land cover and temperature data from 109 sampling points. We used structural equation modelling to estimate direct and indirect effects of local climate on bird abundance. We obtained a sufficient sample for 15 species, characterized by a broad variety of ecological requirements. For all species we found a significant indirect effect of local temperatures via vegetation on bird abundance. Direct effects of temperature were less common and were observed in seven woodland/shrubland species, including only mountain generalists; in these cases, local temperatures showed a positive effect, suggesting that on average our study area is likely colder than the thermal optimum of those species. The generalized occurrence of indirect temperature effects within our species set demonstrates the importance of considering both climate and land cover changes to obtain more reliable predictions of future species distribution/abundance. In fact, many species may be largely tracking suitable habitat rather than thermal niches, especially among homeotherm organisms like birds.

Bimodal activity of diurnal flower visitation at high elevation.

Successful pollination in animal-pollinated plants depends on the temporal overlap between flower presentation and pollinator foraging activity. Variation in the temporal dimension of plant-pollinator networks has been investigated intensely across flowering seasons. However, over the course of a day, the dynamics of plant-pollinator interactions may vary strongly due environmental fluctuations. It is usually assumed there is a unimodal, diurnal, activity pattern, while alternative multimodal types of activity patterns are often neglected and deserve greater investigation. Here, we quantified the daily activity pattern of flower visitors in two different habitats contrasting high elevation meadows versus forests in Southwest China to investigate the role of abiotic conditions in the temporal dynamics of plant-pollinator interactions. We examined diurnal activity patterns for the entire pollinator community. Pollinator groups may differ in their ability to adapt to habitats and abiotic conditions, which might be displayed in their patterns of activity. We hypothesized that (a) pollinator communities show multimodal activity patterns, (b) patterns differ between pollinator groups and habitat types, and (c) abiotic conditions explain observed activity patterns. In total, we collected 4,988 flower visitors belonging to six functional groups. There was a bimodal activity pattern when looking at the entire pollinator community and in five out of six flower visitor groups (exempting solitary bees) regardless of habitat types. Bumblebees, honeybees, dipterans, lepidopterans, and other insects showed activity peaks in the morning and afternoon, whereas solitary bees were most active at midday. Activity of all six pollinator groups increased as solar radiation increased and then decreased after reaching a certain threshold. Our findings suggest that in habitats at higher elevations, a bimodal activity pattern of flower visitation is commonly employed across most pollinator groups that are diurnal foragers. This pattern may be caused by insects avoiding overheating due to elevated temperatures when exposed to high solar radiation at midday.

De novo Assembly, Annotation, and Analysis of Transcriptome Data of the Ladakh Ground Skink Provide Genetic Information on High-Altitude Adaptation.

The Himalayan Arc is recognized as a global biodiversity hotspot. Among its numerous cryptic and undiscovered organisms, this composite high-mountain ecosystem harbors many taxa with adaptations to life in high elevations. However, evolutionary patterns and genomic features have been relatively rarely studied in Himalayan vertebrates. Here, we provide the first well-annotated transcriptome of a Greater Himalayan reptile species, the Ladakh Ground skink Asymblepharus ladacensis (Squamata: Scincidae). Based on tissues from the brain, an embryonic disc, and pooled organ material, using pair-end Illumina NextSeq 500 RNAseq, we assembled ~77,000 transcripts, which were annotated using seven functional databases. We tested ~1600 genes, known to be under positive selection in anurans and reptiles adapted to high elevations, and potentially detected positive selection for 114 of these genes in Asymblepharus. Even though the strength of these results is limited due to the single-animal approach, our transcriptome resource may be valuable data for further studies on squamate reptile evolution in the Himalayas as a hotspot of biodiversity.

Phenotypic and genomic adaptations to the extremely high elevation in plateau zokor (Myospalax baileyi).

The evolutionary outcomes of high elevation adaptation have been extensively described. However, whether widely distributed high elevation endemic animals adopt uniform mechanisms during adaptation to different elevational environments remains unknown, especially with respect to extreme high elevation environments. To explore this, we analysed the phenotypic and genomic data of seven populations of plateau zokor (Myospalax baileyi) along elevations ranging from 2,700 to 4,300 m. Based on whole-genome sequencing data and demographic reconstruction of the evolutionary history, we show that two populations of plateau zokor living at elevations exceeding 3,700 m diverged from other populations nearly 10,000 years ago. Further, phenotypic comparisons reveal stress-dependent adaptation, as two populations living at elevations exceeding 3,700 m have elevated ratios of heart mass to body mass relative to other populations, and the highest population (4,300 m) displays alterations in erythrocytes. Correspondingly, genomic analysis of selective sweeps indicates that positive selection might contribute to the observed phenotypic alterations in these two extremely high elevation populations, with the adaptive cardiovascular phenotypes of both populations possibly evolving under the functional constrains of their common ancestral population. Taken together, phenotypic and genomic evidence demonstrates that heterogeneous stressors impact adaptations to extreme elevations and reveals stress-dependent and genetically constrained adaptation to hypoxia, collectively providing new insights into the high elevation adaptation.

Two new species of doryline ants (Hymenoptera, Formicidae) with 11-segmented antennae from India.

Two new species of the subfamily Dorylinae Leach, 1815 namely Parasysciaganeshaiahi sp. nov. and Sysciaindica sp. nov. are described and illustrated based on the worker caste. These species were collected in the Eaglenest Wildlife Sanctuary, Arunachal Pradesh, Northeast India. Keys to Parasyscia of India and Syscia of Asia are provided based on the worker caste.