Temperate Habitats Research Articles

Novel Ser74 of NF-κB/IκBα phosphorylated by MAPK/ERK regulates temperature adaptation in oysters.

Phosphorylation of Ser32 and Ser36 controls the degradation of IκBα is the conserved cascade mechanisms of immune core signaling pathway, NF-κB pathway in metazoans, but it's response to abiotic stress and the presence of novel phosphorylation mechanisms in other species remain unclear. Herein, we reported a novel heat-induced phosphorylation site (Ser74) at oysters' major IκBα, which independently regulated ubiquitination-proteasome degradation without the requirement of phosphorylation at S32 and S36. And this site was phosphorylated by ERK/MAPK pathway, which then promoted REL nuclear translocation to activate cell survival related genes to defend heat-stress. The MAPK-NF-κB cascade exhibited divergent thermal responses and adaptation patterns between two congeneric oyster species with differential habitat temperatures, indicating its involvement in shaping temperature adaptation. This study demonstrated that the existence of complex and unique phosphorylation-mediated signaling transduction mechanism in marine invertebrates, and expanded our understanding of the evolution and function of established classical pathway crosstalk mechanisms.

Genomic Insights into Pig Domestication and Adaptation: An Integrated Approach Using Genome-Wide Selection Analysis and Multiple Public Datasets.

As a global focus of animal husbandry, pigs provide essential meat resources for humans. Therefore, analyzing the genetic basis of adaptability, domestication, and artificial selection in pigs will contribute to further breeding. This study performed a genome-wide selection sweep analysis to identify candidate genes related to domestication and adaptive selection via data from 2413 public genotypes. Two complementary statistical analyses, FST (fixation index) and XP-EHH (cross-population extended haplotype homozygosity) were applied. The results revealed that numerous candidate genes were associated with high-altitude adaptability (e.g., SIRPA, FRS2, and GRIN2B) and habitat temperature adaptability (e.g., MITF, PI3KC2A, and FRS2). In addition, candidate genes related to the domestic genetic imprint of indigenous pigs (e.g., TNR, NOCT, and SPATA5) and strong artificial selection pressure in commercial breeds (e.g., ITPR2, HSD17B12, and UGP2) were identified in this study. Specifically, some MHC-related genes (e.g., ZRTB12, TRIM26, and C7H6orf15) were also under selection during domestication and artificial selection. Additionally, a phylogenetic comparative analysis revealed that the genetic divergence between populations does not fully follow the geographical distribution and management history in the major histocompatibility complex region/major histocompatibility complex II haplotypes, unlike that of the genome-wide genotypes. Furthermore, the higher heterozygosity and haplotype alleles of MHC reduce the differences between populations. Briefly, this study not only helps promote the relative theoretical understanding of environmental adaptive selection and domestication but also provides a theoretical reference for disease-resistant breeding in pigs.

Interpreting the shifts in forest structure, plant community composition, diversity, and functional identity by using remote sensing-derived wildfire severity

BackgroundWildfires are increasingly impacting ecosystems worldwide especially in temperate dry habitats, often interplaying with other global changes (e.g., alien plant invasions). Understanding the ecological consequences of wildfires is crucial for effective conservation and management strategies. The aim of this study was to investigate the impacts of wildfire severity on plant community (both the canopy trees and herbaceous layer) and alien plant invasion, combining field observations and remotely sensed data.We conducted an observational study in the Karst forests (North-East Italy) 1 year after the large wildfire which affected the area in 2022. We assessed the impact through 35 field plots (200 m2 each) distributed among different fire severity (i.e., the loss of organic matter) classes assessed using the differenced normalized burn ratio (dNBR) calculated from satellite images. In each plot, tree species, diameter, vitality, resprouting capacity, and seedling density were measured. In addition, herb species richness (taxonomical diversity) was quantified, and plant cover was visually estimated. Functional diversity was also assessed considering six functional traits retrieved from databases.ResultsSome woody species (e.g., Quercus pubescens) showed a higher resistance to the fire (i.e., lower mortality rate), while others showed a higher resilience (i.e., recovery after fire through resprouting or seedlings, e.g., Cotinus coggygria). The transition to a shrub-dominated community (i.e., Cotinus coggygria) where fire severity was the highest underlines the dynamic nature of the post-fire succession. We detected a significant variation in the herbaceous plant community composition, diversity, and functional identity (i.e., community-weighted mean of trait) along the fire severity gradient. In particular, high-fire severity areas exhibited higher species richness compared to low-severity or unburned areas. Total alien plant cover increased with fire severity, while native cover remained constant. We also found shifts in species that enhance traits related to germination potential and growth strategy.ConclusionsOur results highlight the vulnerability of the forest stands to an increase in wildfire severity, resulting in significant mortality and changes in tree community structure. This study contributes to the understanding of ecological processes after wildfires using a novel remote sensing approach in a temperate forest, emphasizing the need for conservation strategies aimed at mitigating high severity wildfires.

Rapid assessment implementation in the development of biocriteria and organic enrichment evaluation in the Citarum River, Indonesia

ABSTRACT Socio-economic activities along the Citarum River basin in Indonesia can induce ecological disturbances in the structure of the benthic macroinvertebrate community. This research aims to (1) identify the environmental factors responsible (2) describe the ecological disturbances using biological measurements; (3) and to develop local biocriteria using a multi-metric conceptual approach. An inventory of benthic macroinvertebrates was carried out at eight stations over a sampling period of 3 months, along with water quality monitoring. The results confirm the change in the structure of benthic macroinvertebrate communities, explained by seven environmental parameters: dissolved oxygen (DO), ambient habitat quality, turbidity, nutrient enrichment, conductivity, temperature, and embeddedness percentage. The changes were then assessed using six biological measurements. Only four have been shown to be capable as alternatives to existing biocriteria. Their implementation enabled the development of local biocriteria compatible with the multimetric concept known as the cumulative biotic index (CBI).

Freezing stress tolerance of benthic freshwater diatoms from the genus Pinnularia: Comparison of strains from polar, alpine, and temperate habitats.

Diatoms are among the most important primary producers in alpine and polar freshwaters. Although temperate diatoms are sensitive to freezing, polar diatoms often exhibit more resistance. This is particularly true for members of the (predominantly terrestrial) Pinnularia borealis species complex. However, it remains unclear to what extent this resistance applies to other representatives of the genus. Here, we compare the freezing-stress tolerance of 11 freshwater, benthic strains representing different species of Pinnularia (including Caloneis) from polar, alpine, and temperate habitats. As vegetative cells, strains were exposed to freezing temperatures of -4, -10, -20, -40, -80, and -196°C. Survival was assessed by light microscopy and photosynthetic measurements. We observed vegetative cells to be sensitive to low freezing temperatures; only "mild" freezing was survived by all tested strains, and most tested strains did not survive treatments ≤-10°C. However, individual strain sensitivities appeared related to their original habitats. For example, polar and alpine strains better withstood "mild" and "moderate" freezing (-4 and -10°C, respectively); although temperate strains were significantly affected by the "mild" freezing treatment, polar and alpine strains were not. The -10°C treatment was survived exclusively by polar strains, and only P. catenaborealis survived all treatments. Interestingly, this species exhibited the lowest survival in the -10°C treatment, potentially implying some metabolic activity even at freezing temperatures. Thus, despite more extensive sampling throughout the genus and finer temperature scaling compared to previous studies, the remarkable freezing-stress tolerance of the P. borealis species complex remains unique within the genus.

Estuarine ichthyofauna of Kamchatka: formation conditions, species diversity and ecological characterisation

Species composition of the estuarine ichthyofauna is described for the first time on a regional scale for Kamchatka Territory based on the materials of author’s field studies carried out in 2010–2022, as well as on the analysis of all available information (literature, archival, survey, fishery, etc.). Specific features of the conditions of formation of estuarine ichthyofauna of the region are revealed. Fish species dominating in abundance in Kamchatka estuaries are indicated. The main ecological groups (guilds) of estuarine fishes are outlined. It was found that 1 species of cyclostomes and 60 species of fishes belonging to 44 genera and 23 families can be attributed to the estuarine ichthyofauna of Kamchatka. All these species are, to varying degrees, euryhaline and therefore may utilize individual Kamchatka estuaries as habitats at various stages of the life cycle. The basis of species diversity of the ichthyofauna of Kamchatka estuaries is formed by marine fishes (at least 34 species), the second in importance are anadromous species (1 species of cyclostomes and 14 species of fishes), the minimum contribution belongs to freshwater resident fishes (13 species), which are found only in estuaries of some rivers of the region. Fish that can be referred to the ecological group of “solely estuarine” (i. e., those whose full life cycle takes place in estuaries) are probably absent in Kamchatka. The maximum species diversity of fish communutues is observed either in big Kamchatka estuaries that are largely open to the sea or in river basins with a diverse freshwater ichthyofauna. Environmental conditions in such estuaries are more favorable for the migrations and habitat of marine fish species (mainly coastal ichthyocene). At the same time, all anadromous or some freshwater euryhaline species may also use these same estuaries as temporary habitats at certain stages of the life cycle. Fish species diversity is significantly higher in the estuaries of the eastern coast of Kamchatka, which is explained by the milder climatic conditions of this area (compared to the coast of the Sea of Okhotsk), as well as by the greater typological diversity of estuaries. A separate section summarizes the currently available information on the biology and ecology of all species of fishes and fish of Kamchatka estuaries, which is presented in the form of brief species sketches (including, external view at individual stages of the life cycle; key morphological characters; maximum size and age; distribution over the territory of the region; habitat specifics, lifestyle and migrations; peculiarities of reproduction and development; feeding preferences; abundance in the region, commercial or economic importance).

A new species of Thermocyclops Kiefer, 1927 (Crustacea, Copepoda, Cyclopoida, Cyclopidae) from temporary habitats, with a discussion on the diversity and distribution of the genus in Thailand

Thermocyclops Kiefer, 1927, is a genus of Cyclopidae, one of the most diverse families among cyclopoids. To date, 13 species of this genus have been recorded in Thailand. Through intensive sampling of rice fields in central Thailand and temporary waters in northeastern Thailand, one new species, Thermocyclops oryzaesp. nov., was discovered. This new species is clearly distinguished from other Thermocyclops by the presence of a serrated lobe on the posterior surface of the medial expansion of the basipodite of the fourth swimming leg. Moreover, it can be distinguished from its congeners by (i) ornamentation on the genital double-somite, succeeding two urosomites and caudal ramus; (ii) the length and width ratio of the caudal ramus; (iii) the length ratio of the innermost terminal seta (VI) and the outermost terminal seta (III); (iv) the number of setae on the second endopodal segment of the antenna; (v) projection and ornamentation on the intercoxal sclerites of the first to fourth swimming legs; (vi) the surface ornamentation of the medial margin of the basipodite of the first to fourth swimming legs; and (vii) the relative length of two apical spines of the third endopodal segment of the fourth swimming leg. The present discovery increases the number of species in this genus in Thailand to 14. A pictorial key to all species is proposed, and their ecologies and distributions within Thailand are updated and discussed.

Freshwater Turtles in an Arid Land: Population Ecology, Habitat and Ecological Niche Modelling of Pelomedusa subrufa olivacea in the Sahel

ABSTRACTTurtle ecology and conservation have been poorly explored in the West African Sahel regions, and this scarce information has produced a suboptimal management of their populations in the wild. In order to enhance the knowledge on the Sahelian turtle ecology, a field study was carried out in Burkina Faso on the ecology of Pelomedusa subrufa olivacea, a freshwater species inhabiting a wide range of waterbodies throughout West Africa. Reasoned sampling was carried out, resulting in the collection of a total of 196 individuals of Pelomedusa subrufa olivacea. This species shows a relatively balanced distribution of age and sex classes of individuals surveyed in the different study areas. The majority of individuals were observed in specific habitats, confirmed by an aggregative distribution. The potential habitats identified by the MaxEnt model highlight key areas for the conservation of this species in Burkina Faso. Conservation efforts should focus on protecting and restoring temporary and permanent aquatic habitats, and managing human activities to minimize the impact on turtle populations in the West African Sahel.

Large branchiopods (Anostraca, Notostraca, Laevicaudata, Spinicaudata) from the semi-arid regions of western India

Abstract Large branchiopod crustaceans are flagship species of temporary water bodies, especially in arid and semi-arid regions. Less information is available about the large branchiopods of tropical Asia compared to other parts of the world such as the Americas. To reduce this disparity, we surveyed large branchiopods from the semi-arid region of Maharashtra state, India. Sampling at 29 sites over four years revealed nine species representing four orders. This is the highest diversity ever reported from a single regional study in India. Anostracans were the most commonly occurring group, whereas the spinicaudatans Leptestheria cf. nobilisSars, 1900, L. jaisalmerensisTiwari, 1962, and Eulimnadia michaeliNayar & Nair, 1968 were very rare. Leptestheria jaisalmerensis had been known previously only from its type locality nearly 1,200 km north of our study region. Congeneric assemblages of the anostracans Streptocephalus dichotomusBaird, 1860 + S. simplexGurney, 1906 and the spinicaudatans Leptestheria cf. nobilis + L. jaisalmerensis were collected. Temporary aquatic habitats are threatened due to adverse anthropogenic activities, especially in developing countries like India. The endemic species of large branchiopods in the Indian subcontinent should be red-listed, as is done elsewhere.

Mapping of temperate upland habitats using high-resolution satellite imagery and machine learning

Upland habitats provide vital ecological services, yet they are highly threatened by natural and anthropogenic stressors. Monitoring these vulnerable habitats is fundamental for conservation and involves determining information about their spatial locations and conditions. Remote sensing has evolved as a promising tool to map the distribution of upland habitats in space and time. However, the resolutions of most freely available satellite images (e.g., 10-m resolution for Sentinel-2) may not be sufficient for mapping relatively small features, especially in the heterogeneous landscape—in terms of habitat composition—of uplands. Moreover, the use of traditional remote sensing methods, imposing discrete boundaries between habitats, may not accurately represent upland habitats as they often occur in mosaics and merge with each other. In this context, we used high-resolution (2 m) Pleiades satellite imagery and Random Forest (RF) machine learning to map habitats at two Irish upland sites. Specifically, we investigated the impact of varying spatial resolutions on classification accuracy and proposed a complementary approach to traditional methods for mapping complex upland habitats. Results showed that the accuracy generally improved with finer spatial resolution data, with the highest accuracy values (80.34% and 79.64%) achieved for both sites using the 2-m resolution datasets. The probability maps derived from the RF-based fuzzy classification technique can represent complex mosaics and gradual transitions occurring in upland habitats. The presented approach can potentially enhance our understanding of the spatiotemporal dynamics of habitats over large areas.

Comparative Genomics Supports Ecologically Induced Selection as a Putative Driver of Banded Penguin Diversification.

The relative importance of genetic drift and local adaptation in facilitating speciation remains unclear. This is particularly true for seabirds, which can disperse over large geographic distances, providing opportunities for intermittent gene flow among distant colonies that span the temperature and salinity gradients of the oceans. Here, we delve into the genomic basis of adaptation and speciation of banded penguins, Galápagos (Spheniscus mendiculus), Humboldt (Spheniscus humboldti), Magellanic (Spheniscus magellanicus), and African penguins (Spheniscus demersus), by analyzing 114 genomes from the main 16 breeding colonies. We aim to identify the molecular mechanism and genomic adaptive traits that have facilitated their diversifications. Through positive selection and gene family expansion analyses, we identified candidate genes that may be related to reproductive isolation processes mediated by ecological thermal niche divergence. We recover signals of positive selection on key loci associated with spermatogenesis, especially during the recent peripatric divergence of the Galápagos penguin from the Humboldt penguin. High temperatures in tropical habitats may have favored selection on loci associated with spermatogenesis to maintain sperm viability, leading to reproductive isolation among young species. Our results suggest that genome-wide selection on loci associated with molecular pathways that underpin thermoregulation, osmoregulation, hypoxia, and social behavior appears to have been crucial in local adaptation of banded penguins. Overall, these results contribute to our understanding of how the complexity of biotic, but especially abiotic, factors, along with the high dispersal capabilities of these marine species, may promote both neutral and adaptive lineage divergence even in the presence of gene flow.

Within the optimal thermal range, temperature fluctuations with similar means have little effect on offspring phenotypes: A comparison of two approaches that simulate natural nest conditions

Temperature influences nearly every aspect of organismal function. Because aspects of global change such as urbanization and climate change influence temperature, researchers must consider how altering thermal regimes will impact biodiversity across the planet. To do so, they often measure temperature in natural and/or human-modified habitats, replicate those temperatures in laboratory experiments to understand organismal responses, and make predictions under models of future change. Consequently, accurately representing temperature in the laboratory is an important concern, yet few studies have assessed the consequences of simulating thermal conditions in different ways. We used nest temperatures for two urban-dwelling, invasive lizards (Anolis sagrei and A. cristatellus) to create two egg incubation treatments in the laboratory. Like most studies of thermal developmental plasticity, we created daily repeating thermal fluctuations; however, we used different methods to create temperature treatments that differed in the magnitude and breadth of thermal cycles, and then evaluated the effects of these different approaches on embryo development and hatchling phenotypes. Additionally, we measured embryo heart rate, a proxy for metabolism, across temperature to understand the immediate effects of treatments. We found that treatments had minimal effect on phenotypes likely because temperatures were within the optimal thermal range for each species and were similar in mean temperature. We conclude that slight differences in thermal treatments may be unimportant so long as temperatures are within a range appropriate for development, and we make several recommendations for future studies of developmental plasticity.

Unravelling the complexities of biotic homogenization and heterogenization in the British avifauna.

Biotic homogenization is a process whereby species assemblages become more similar through time. The standard way of identifying the process of biotic homogenization is to look for decreases in spatial beta-diversity. However, using a single assemblage-level metric to assess homogenization can mask important changes in the occupancy patterns of individual species. Here, we analysed changes in the spatial beta-diversity patterns (i.e. biotic heterogenization or homogenization) of British bird assemblages within 30 km × 30 km regions between two periods (1988-1991 and 2008-2011). We partitioned the change in spatial beta-diversity into extirpation and colonization-resultant change (i.e. change in spatial beta-diversity within each region resulting from both extirpation and colonization). We used measures of abiotic change in combination with Bayesian modelling to disentangle the drivers of biotic heterogenization and homogenization. We detected both heterogenization and homogenization across the two time periods and three measures of diversity (taxonomic, phylogenetic, and functional). In addition, both extirpation and colonization contributed to the observed changes, with heterogenization mainly driven by extirpation and homogenization by colonization. These assemblage-level changes were primarily due to shifting occupancy patterns of generalist species. Compared to habitat generalists, habitat specialists had significantly (i) higher average contributions to colonization-resultant change (indicating heterogenization within a region due to colonization) and (ii) lower average contributions to extirpation-resultant change (indicating homogenization from extirpation). Generalists showed the opposite pattern. Increased extirpation-resultant homogenization within regions was associated with increased urban land cover and decreased habitat diversity, precipitation, and temperature. Changes in extirpation-resultant heterogenization and colonization-resultant heterogenization were associated with differences in elevation between regions and changes in temperature and land cover. Many of the 'winners' (i.e. species that increased in occupancy) were species that had benefitted from conservation action (e.g. buzzard (Buteo buteo)). The 'losers' (i.e. those that decreased in occupancy) consisted primarily of previously common species, such as cuckoo (Cuculus canorus). Our results show that focusing purely on changes in spatial beta-diversity over time may obscure important information about how changes in the occupancy patterns of individual species contribute to homogenization and heterogenization.

Insects in temperate urban parks face stronger selection pressure from the cold than the heat.

Urban areas experience higher temperatures compared to rural areas and as such, are increasingly considered places of acclimatization and adaptation to warming. Small ectotherms, such as insects, whose body temperature rises with habitat temperature, are directly affected by temperature changes. Thus, warming could have a profound effect on insect behavior and physiology. To test if the urban heat island effect drives higher thermal tolerance and activity changes, we used globally distributed and abundant insects-ants. We measured the heat and cold tolerance of 14 ant species distributed across urban and peri-urban areas. As thermal traits are often correlated with ant foraging, we measured foraging activity during three consecutive years across eight sites. Contrary to our prediction, ants exposed to the urban heat island effect did not have a higher heat tolerance than peri-urban ants. Instead, cold tolerance varied across habitats, with ants from the cooler, peri-urban habitats being able to tolerate lower temperatures. We recorded the same pattern of invariant heat and higher cold tolerance for ants in the canopy, compared to ground nesting ants. Ant activity was almost 10 times higher in urban sites and best predicted by cold, not heat tolerance. These unexpected results suggest that we need to rethink predictions about urban heat islands increasing insect heat tolerance in urban habitats, as cold tolerance might be a more plastic or adaptable trait, particularly in the temperate zone.

Leaf functional traits of Parrotia subaequalis from different environments in eastern China.

Functional traits are important in understanding how plants respond and adapt to their immediate environment. Parrotia subaequalis is a highly endangered arbor species found throughout eastern China, primarily inhabiting hillsides and valleys, yet, little is known about the variation in leaf traits across these environments. In the present study, we tested this by comparing leaf surface area, leaf weight, leaf length, leaf symmetry and leaf mass per unit area, as well as the relationship between leaf traits and environmental factors and the scaling relationship between leaf surface area versus leaf dry mass. We observed significant differences in leaf surface area, weight, and length among the population sites, and these variables were strongly affected by environmental factors, especially high mean annual temperatures in hillside habitats and high mean annual precipitation in valley habitats. The scaling exponents remained numerically variant among the 10 populations, with different slopes greater than 1.0, and the scaling exponents increased significantly with hillside habitats. These metrics correlated with soil thickness associated with different habitat types. The areal ratio (AR) values in all populations deviated from 1, indicating that the two lamina sides were asymmetrical. The standardized symmetry index (SI) values displayed significant variation, especially in leaves from hillside habitats with a high degree of asymmetry. Collectively, our findings demonstrated that leaf functional traits exhibit considerable variability in response to different environmental contexts and provide valuable reference data that could be useful for conserving this endangered species.

Toxicity of rare earth elements (REEs) to marine organisms: Using species sensitivity distributions to establish water quality guidelines for protecting marine life

A lack of chronic rare earth element (REE) toxicity data for marine organisms has impeded the establishment of numerical REE water quality benchmarks (e.g., guidelines) to protect marine life and assess ecological risk. This study determined the chronic no (significant) effect concentrations (N(S)ECs) and median-effect concentrations (EC50s) of eight key REEs (yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), gadolinium (Gd), dysprosium (Dy) and lutetium (Lu)) for 30 coastal marine organisms (encompassing 22 phyla and five trophic levels from temperate and tropical habitats). Organisms with calcifying life stages were most vulnerable to REEs, which competitively inhibit calcium uptake. The most sensitive organism was a sea urchin, with N(S)ECs ranging from 0.64 μg/L for Y to 1.9 μg/L for La and Pr, and EC50s ranging from 4.3 μg/L for Y to 14.4 μg/L for Pr. Conversely, the least sensitive organism was a cyanobacterium, with N(S)ECs ranging from 121 μg/L for Y to 469 μg/L for Pr, and EC50s ranging from 889 μg/L for Y to 3000 μg/L for Pr. Median sensitivity varied 215-fold across all organisms. The two-fold difference in median toxicity (μmol/L EC50) among REEs (Y ∼ Gd > Lu ∼ Nd ∼ Dy ∼ Ce > La ∼ Pr) was attributed to offset differences in binding affinity (log K) to cell surface receptors and the percentage of free metal ion (REE3+) in the test waters. The toxicity (EC50) of the remaining REEs (samarium, europium, terbium, holmium, thulium and ytterbium) was predicted using a combination of physicochemical data and measured EC50s for the eight tested REEs, with good agreement between predicted and measured EC50s for selected organisms. Numerical REE water quality guidelines to protect marine life were established using species sensitivity distributions (e.g., for 95 % species protection, values ranged from 1.1 μg/L for Y to 3.0 μg/L for La, Pr or Lu).

Early life exposure to high temperature enhances locomotor performance without alteration in thermal ecology in different populations of Thoropa taophora tadpoles (Anura, Cycloramphidae).

Understanding the intricate relationship between temperature and physiological processes in ectotherm vertebrates is crucial for predicting how these animals respond to environmental changes, including those associated with climate change. This is particularly relevant for the anurans, given their limited capacity for thermoregulation, particularly in larval stages. Herein, we investigated the capacity for thermal acclimatization in Thoropa taophora tadpoles, an endemic species in the Atlantic rainforest of Southeast Brazil, inhabiting distinct thermal environments. These semi-terrestrial tadpoles develop on rocky surfaces with some populations inhabiting exposed regions near the marine coast where temperatures may reach up to 30 °C in sunny conditions, while other populations occupy forested areas near waterfalls that maintain lower temperatures. We aimed to understand the effects of temperature on locomotor performance and on the activity of metabolic enzymes that support performance in tadpoles sampled in four different populations. Moreover, we measured several aspects of thermoregulation including the critical thermal maximum (CTmax), the body temperature of activity (Tb), the preferred temperature (Tpref) and the effectiveness of thermoregulation (E). Despite differences in body size, tadpoles from warmer environments consistently demonstrate higher locomotor performance, with minimal or no acclimatization seen in other variables. Correlations between habitat temperature and biological endpoints underscore the significance of maximum locomotor performance in shaping physiological responses. Our results show how temperature can impact tadpole behavior and performance, without change in many organismal measures of thermal acclimatization, providing insights into potential ecological implications, particularly in the context of climate change.

Efficacy of sugar‐protein non‐membranous dietary system for diapause egg production in Aedes albopictus mosquitoes under short‐day conditions

AbstractThe Asian tiger mosquito, Aedes albopictus (Skuse) (Diptera: Culicidae), is a global vector of dengue, chikungunya and zika viruses. With extreme adaptability of survival as diapause eggs, this mosquito has invaded and established in temperate climatic zones. The diapause eggs are specially programmed to overcome the harsh winter conditions in temperate habitats. In the laboratory, diapausing females are reared from early larval instars under short‐day conditions (21°C and 16D:8 L photoperiods). Aedes albopictus is normally fed on Guinea pigs for the rearing of diapause mosquitoes which requires ethical approval from the animal use committee and costly arrangements. Therefore, the present study was conducted to find whether bovine serum albumin protein (10%) with sucrose (5%) solution (SAP‐10) offered through a membrane‐free feeding system would result in an alternative diet for the production of diapause eggs in comparison to blood‐feeding. This feeding system shows a considerable rate of engorgement of diapausing females under short‐day conditions and produced 30.8 diapause eggs/female in comparison to blood‐feeding on a guinea pig (40.9 eggs/female). The diapause rate of viable eggs for the SAP‐10 diet (95.28%) was similar to the blood‐feeding (96.32%). The findings suggest that the present diet feeding system is a promising tool for the rearing of diapause Ae. albopictus mosquitoes under short‐day conditions. Further studies are suggested to evaluate the physiological and developmental aspects of mosquitoes reared on the diet.

Tardigrade distribution in soils of high Arctic habitats.

Tardigrades are omnipresent microfauna with scarce record on their ecology in soils. Here, we investigated soil inhabiting tardigrade communities in five contrasting polar habitats, evaluating their abundance, diversity, species richness, and species composition. Moreover, we measured selected soil physico-chemical properties to find the drivers of tardigrade distribution among these habitats. In spite of reported tardigrade viability in extreme conditions, glacier forelands represented a habitat almost devoid of tardigrades. Even dry and wet tundra with soil developing for over more than 10000 years held low abundances compared to usual numbers of tardigrades in temperate habitats. Polar habitats also differ in species composition, with Diaforobiotus islandicus being typical species for dry and Hypsibius exemplaris for wet tundra. Overall, tardigrade abundance was affected by the content of nutrients as well as physical properties of soil, i.e. content of total nitrogen (TN), total organic carbon (TOC), stoniness, soil texture and the water holding capacity (WHC). While diversity and species composition were significantly related to soil physical properties such as the bulk density (BD), soil texture, stoniness, and WHC. Physical structure of environment was, therefore, an important predictor of tardigrade distribution in polar habitats. Since many studies failed to identify significant determinants of tardigrade distribution, we encourage scientists to include physical properties of tardigrade habitats as explanatory variables in their studies.

Bring on the heat: thermal ecology of Tropidurus semitaeniatus in the Northeast of Brazil

Body temperature is a key physiological trait for individual fitness. Its effects on behavior and metabolism determine organismal activity. Optimal body temperature can vary among individuals, and consequent activity asynchrony can thus enable the co-occurrence of otherwise competing social strategies. Here, we combine ex-situ experiments with environmental data to test whether variability in thermal traits can explain the maintenance of the alternative reproductive strategies of Tropidurus semitaeniatus (Spix, 1825) male morphs. We predict that morphs and sexes differ in thermal traits. Thus, we tested for differences in their behaviorally determined thermal traits: preferred ( Tp), body ( Tb), and habitat temperatures; basking cover preference (Coverpref); and physiological limits (critical thermal minimum CTmin; and maximum, CTmax). We also calculated T. semitaeniatus’ thermal tolerance traits and compiled a list of Tp for Tropidurids. We found that T. semitaeniatus maintains its Tb below Tp. In addition, and contrary to theoretical predictions for tropical lizards, we found that T. semitaeniatus has a high warming tolerance (8.3 °C) and thermal safety margin (2.4 °C). We found no thermal differences between morphs indicating that thermal ecology does not play a role in the co-existence of color morphs.