Northern Populations Research Articles

Over-winter body mass and conceptions of white-tailed deer in central Texas

At lower latitudes ungulate reproduction is often seasonal, but the duration of mating and parturition seasons can be long. To further understand the adaptive significance of synchrony in reproductive events, we examined two hypotheses to link over-winter body mass with lower synchrony of conceptions in a wild population of white-tailed deer ( Odocoileus virginianus (Zimmermann, 1780)) in central Texas. If females maintain over-winter body mass, then the window of time that conception occurs should be relaxed and longer relative to females where over-winter body mass declines. Across 9 years, we measured body mass in 1.5-year-old and older females in November ( n = 170) and in March (118). In March, we also measured forehead–rump lengths in offspring of gravid females and calculated conception dates. Over-winter body mass did not decline but was maintained, on average, across the years of study. Conception dates ranged over 50 days and 52% of conceptions occurred in a 2-week period centered on the median conception date. Relative to northern populations of deer, there was lower synchrony in conception dates. White-tailed deer across the geographic range appear to be flexible in over-winter body mass dynamics that affects duration of reproductive events such as conception.

Striped Bass Movement in a Large Southeastern River System

Abstract Migratory behaviors of coastal Striped Bass Morone saxatilis are diverse and vary by latitude along the U.S. Atlantic Coast. Northern populations (e.g., north of Cape Hatteras, North Carolina) are anadromous, with spawning occurring in tidal freshwater/brackish rivers and adults leaving spawning locations during the winter to conduct north–south coastal migrations. The central Atlantic comprises a mixture of potamodromous and anadromous types, completing the natural continuum of behavioral modes along latitudinal ecotones. Southern populations (e.g., south of Cape Hatteras, North Carolina) are typically resident and potamodromous, completing full life cycles within river systems, and do not migrate along the Atlantic Coast. There are limited studies that have investigated daily movement of Striped Bass in the Southeast and no studies have documented movement of Striped Bass in the Great Pee Dee River, particularly with reference to spawning migrations. The objective of this study was to describe daily movement patterns and centers of attraction (e.g., spawning and resting stages) of Striped Bass in the Great Pee Dee River, South Carolina. We implanted 10 fish with hydroacoustic transmitters between 2013 and 2016. We describe daily movement and behavior using the state-space model with a two-dimensional spatial coordinate system. We recorded a total of 94,857 data points across all individuals and receivers. We observed two movement patterns. One group completed a seasonal migration (i.e., were recorded swimming upstream or downstream) that coincides with spring spawning season. A second group was present in the lower river section and Winyah Bay during the winter for 3 consecutive years but were never observed migrating up the Great Pee Dee River during the spring. One individual was documented swimming 80 river km north in the Atlantic Intracoastal Waterway, suggesting there are important overwintering locations outside their natal river. Additionally, there were significant gaps in observations for all individuals, particularly in the summer. It is possible that fish are leaving the main stem in search of thermal refuge within small tributaries. Identifying these overwintering areas and tributaries that serve as summer refuge is needed to determine stressors and fishing pressure of this important species.

Evidence for a selective link between cooperation and individual recognition

The ability to recognize others is a frequent assumption of models of the evolution of cooperation. At the same time, cooperative behavior has been proposed as a selective agent favoring the evolution of individual recognition abilities. Although theory predicts that recognition and cooperation may co-evolve, data linking recognition abilities and cooperative behavior with evidence of selection are elusive. Here, we provide evidence of a selective link between individual recognition and cooperation in the paper wasp Polistes fuscatus through a combination of clinal, common garden, and population genomics analyses. We identified latitudinal clines in both rates of cooperative nesting and color pattern diversity, consistent with a selective link between recognition and cooperation. In behavioral experiments, we replicated previous results demonstrating individual recognition in cooperative and phenotypically diverse P.fuscatus from New York. In contrast, wasps from a less cooperative and phenotypically uniform Louisiana population showed no evidence of individual recognition. In a common garden experiment, groups of wasps from northern populations formed more stable and individually biased associations, indicating that recognition facilitates group stability. The strength of recent positive selection on cognition-associated loci likely to mediate individual recognition is substantially greater in northern compared with southern P.fuscatus populations. Collectively, these data suggest that individual recognition and cooperative nesting behavior have co-evolved in P.fuscatus because recognition helps stabilize social groups. This work provides evidence of a specific cognitive phenotype under selection because of social interactions, supporting the idea that social behavior can be a key driver of cognitive evolution.

Disproportionate role of nuclear-encoded proteins in organismal and mitochondrial thermal performance in a copepod.

Determining the mechanisms by which organisms evolve thermal tolerance is crucial to predicting how populations may respond to changes in local temperature regimes. Although evidence of relationships between mitochondrial background and thermal adaptation have been found, the presence of both nuclear-encoded and mitochondrial DNA (mtDNA)-encoded proteins warrants experiments aimed at parsing out the relative role of each genome in thermal adaptation. We investigated the relative role of mtDNA-encoded products in thermal tolerance between two divergent populations of Tigriopus californicus using first-generation (F1) hybrids that vary in maternally inherited mtDNA but are heterozygous for population-specific alleles across nuclear loci. We tested two measures of thermal tolerance, (1) survivorship to acute thermal stress and (2) thermal stability of mitochondrial performance in Complex I-fueled ATP synthesis, both across a range of increasing temperatures. We found that the southern population (San Diego, CA, USA) outperformed the northern population (Strawberry Hill, OR, USA) in survivorship, and that both reciprocal F1 hybrid crosses had intermediate survival. Mitochondria from the San Diego population displayed greater stability in ATP synthesis with increasing temperatures compared with those from Strawberry Hill. Interestingly, hybrids from both cross directions had synthesis profiles that were very similar to that of Strawberry Hill. Taken together, these results suggest that the relative role of the mtDNA in these phenotypes is negligible compared with that of elements encoded by nuclear DNA in this system.

Leukocyte immunoglobulin-like receptor A3 gene deletion in five Chinese populations and protective association with nasopharyngeal carcinoma.

Among the thirteen leukocyte Ig-like receptor (LILR) loci located at 19q13.4, LILRA3 is unique in that it encodes a soluble protein lacking the transmembrane and cytoplasmic domains, and a 6.7 kb deletion spanning the first seven exons has been detected in some human individuals. Presently, there is a lack of data about the distribution of LILRA3 gene deletion in more diverse ethnic groups. Also, no previous studies have investigated the correlation between copy number variation (CNV) of LILRA3 and nasopharyngeal carcinoma (NPC). In this study, five populations from China mainland: two Southern Han populations, Hunan (N = 1478) and Guandong (N = 107); one Southeastern Han population, Fujian (N = 439); and two Northern populations, Inner Mongolia Han (N = 104) and Mongol population from Inner Mongolia (N = 158) were investigated for CNV of LILRA3 using polymerase chain reaction-sequence-specific priming (PCR-SSP) method. LILRA3 variants were also examined in a cohort of NPC cases (N = 1142) in Hunan Han population. The five Chinese populations demonstrated northward increase in frequency of the deleted form of LILRA3 gene (LILRA3*Del) (all corrected p values < 0.05). Inter-population comparison also uncovered significant differentiation in the distribution of CNV of LILRA3 among modern human populations. LILRA3*Del was found to confer significantly reduced risk to NPC in Hunan Han population (at allelic level: OR = 0.79, 95% CI = 0.71-0.89, p < 0.0001; at genotype level: OR= 0.63, 95% CI = 0.51-0.79, p < 0.0001). No interaction was found between LILRA3 variants and HLA-A*02:07, HLA-A*11:01, HLA-B*13 and HLA-B*46:01 alleles in susceptibility to NPC. Our study constitutes the first demonstration of LILRA3 gene as a locus linked to NPC susceptibility in a southern Chinese population. Future independent studies in other populations are warranted to confirm the findings reported in this study.

Differences in the reproductive output and larval survival of Rocky Mountain wood ticks (Dermacentor andersoni) and American dog ticks (Dermacentor variabilis) from prairie populations near their northern distributional limits in western Canada.

The effects of temperature and relative humidity (RH) on female reproductive output, egg development and larval survival were determined for Rocky Mountain wood ticks (Dermacentor andersoni) from a prairie population (Chin Lakes, Alberta, Canada) near the northern distribution limit of this species. The responses of D. andersoni eggs and unfed larvae to different temperature (25 or 32°C) and RH (35, 55, 75, 85 or 95%) regimes were compared to our previously published data (Diyes et al. 2021) for a northern prairie population of American dog ticks (Dermacentor variabilis). Oviposition by D. andersoni females took 21-30 days at 25°C and 95% RH compared to 10-21 days for D. variabilis. The number of eggs laid by female ticks was strongly dependent on their engorgement weight, and D. andersoni females produced more eggs than D. variabilis females of an equivalent body weight. Eggs of D. andersoni took less time to develop at 32°C than 25°C with ≥ 85% RH, and hatched faster than those of D. variabilis. Larval survival times declined as temperature increased and RH decreased, but D. andersoni survived longer at 32°C and ≤ 75% RH than D. variabilis. The interspecific differences in responses to the same temperature and humidity regimes indicate that D. andersoni is xerophilic, whereas D. variabilis is hydrophilic. Hence, 'prairie' populations of the Rocky Mountain wood tick occur in the drier grassland ecoregions but are absent in Aspen Parklands Ecoregion which is located to the north and east of the distributional range of D. andersoni.

Habitat fragmentation affects climate adaptation in a forest herb

Abstract Climate change and the resulting increased drought frequencies pose considerable threats to forest herb populations, particularly where additional environmental challenges jeopardize responses to selection. Specifically, habitat fragmentation may hamper climate adaptation by altering the distribution of adaptive genetic variation and may also induce evolutionary changes in mating systems. To assess how habitat fragmentation disrupts climate adaptation, we conducted a common garden experiment with Primula elatior offspring originating from 24 populations sampled along a latitudinal gradient with varying climate and landscape characteristics. We then quantified a range of vegetative, regulatory and reproductive traits under distinct soil moisture regimes to evaluate imprints of local adaptation and phenotypic plasticity. Additionally, we conducted a more extensive field campaign in 60 populations along the same latitudinal gradient to evaluate the potential evolutionary breakdown of reciprocal herkogamy. For large, connected populations, our results demonstrated an evolutionary shift from a strategy in southern populations that seems aligned with drought avoidance—where plants minimize their exposure to dry conditions and optimize photosynthesis—to a drought tolerance strategy in northern populations, where plants are adapted to function despite water scarcity. However, habitat fragmentation disrupted climate clines and the adaptive responses to drought stress in key traits related to growth, biomass allocation and water regulation. Additionally, our findings indicate the onset of evolutionary breakdown in reciprocal herkogamy and divergence in other key flower traits. The disruption of climate clines, drought responses and adaptations in mating systems contributed to a substantially diminished flowering investment across the distribution range, with the most pronounced effects observed in southern fragmented populations. Synthesis. We present novel empirical evidence of how habitat fragmentation disrupts climate adaptation and drought tolerance in a wide range of traits along the range of the forest herb Primula elatior. These findings emphasize the need to account for habitat fragmentation while designing effective conservation strategies in order to preserve and restore resilient meta‐populations of forest herbs amidst ongoing global changes.

Local and regional geographic variation in inducible defenses.

Invasive predators can cause substantial evolutionary change in native prey populations. Although invasions by predators typically occur over large scales, their distributions are usually characterized by substantial spatiotemporal heterogeneity that can lead to patchiness in the response of native prey species. Our ability to understand how local variation shapes patterns of inducible defense expression has thus far been limited by insufficient replication of populations within regions. Here, we examined local and regional variation in the inducible defenses of 12 native marine snail (Littorina obtusata) populations within two geographic regions in the Gulf of Maine that are characterized by vastly different contact histories with the invasive predatory green crab (Carcinus maenas). When exposed in the field to waterborne risk cues from the green crab for 90 days, snails expressed plastic increases in shell thickness that reduced their vulnerability to this shell-crushing predator. Despite significant differences in contact history with this invasive predator, snail populations from both regions produced similar levels of shell thickness and shell thickness plasticity in response to risk cues. Such phenotypic similarity emerged even though there were substantial geographic differences in the shell thickness of juvenile snails at the beginning of the experiment, and we suggest that it may reflect the effects of warming ocean temperatures and countergradient variation. Consistent with plasticity theory, a trend in our results suggests that southern snail populations, which have a longer contact history with the green crab, paid less in the form of reduced tissue mass for thicker shells than northern populations.

Contrasting management paradigms for pronghorn in the arid Southwest and their northern range: a review

AbstractPronghorn (Antilocapra americana), a symbol of western North America, experienced diverging population trajectories since the mid‐twentieth century, with northern populations showing signs of recovery while those in the arid Southwest have struggled to persist. We conducted a systematic literature review of papers published through August 2023 to understand 3 questions. What are the habitat conditions needed for pronghorn to persist? What management actions can be taken to foster higher quality habitat? Do these actions differ for populations in the arid Southwest compared to their northern counterparts? Although the fundamental habitat requirements for pronghorn persistence have remained constant since the early 2000s, it has become clear that precipitation is a key factor influencing pronghorn populations in the arid Southwest. The precise mechanisms by which precipitation influences pronghorn population dynamics are not yet clear, whether through the availability of free water, by affecting forage quality, or indirectly via predator‐prey dynamics. Although range‐wide forage enhancement may be impractical, providing additional free water sources could facilitate greater movement, enabling pronghorn to access more and higher quality forage and areas with lower predation risk. To clarify how pronghorn persisted for thousands of years in this harsh environment, we must gain a better understanding of their historical metapopulation and migratory behaviors in the arid Southwest.

A cultural atlas of vocal variation: yellow-naped amazons exhibit contact call dialects throughout their Mesoamerican range

IntroductionVocal dialects are a taxonomically widespread phenomenon which are typically only studied in a portion of a species’ range. Thus, it is difficult to infer whether a geographic pattern of vocal dialects observed in one part of a species’ range are typical across the range or whether local conditions influence their presence or absence. We examined the yellow-naped amazon, Amazona auropalliata, a parrot species with remarkable vocal learning capabilities. Although this species’ native range spans across Mesoamerica, only Costa Rican populations have been evaluated long-term. Previous studies have shown that these populations have geographically and temporally stable vocal dialect patterns. Without data on populations outside of Costa Rica, it is impossible to know whether vocal dialects are present in northern range populations, and whether they show similar geographic structure to southern range populations.IntroductionWe recorded yellow-naped amazon contact calls at 47 different sites across the species’ range between 2016 and 2019 and evaluated them for the presence of dialects. We visually classified 14 contact call types based on spectrographic similarity and used spectrographic cross-correlation, principal component analysis, and Mantel-based spatial autocorrelations to assess acoustic similarity; we also evaluated the robustness of our findings using simulated data. Results and DiscussionThe results from our study show that the vocal patterns previously seen in Costa Rica are also present in northern populations, supporting our hypothesis that this species has vocal dialects throughout its Mesoamerican range. Call types were regionally specific (e.g., vocal dialects occurred) across the range, and no call types were repeated across multiple regions. We did, however, observe distinctive structural characteristics that are found in multiple call types, suggesting that different call types stem from a common origin. Alternatively, similarity in the acoustic features of call types may also be a result of physiological and anatomical features that are common to all members of the species. Vocal dialects in this species are likely maintained through a tendency toward philopatry and matching call types to enhance social identification.

Benefits of assisted gene flow diminish with latitudinal distance between populations in Chamaecrista fasciculata

In ecological restoration, seed sourcing is often among the first and most critical steps in achieving restored populations that establish and reproduce successfully, while also having the genetic capacity to adapt to future change. Many approaches have been proposed to guide seed sourcing for restoration, including a strong focus on local seed sources, the use of assisted gene flow or assisted migration, and regional admixture provenancing. The goal of this research was to evaluate these issues in the context of grassland restoration. We collected seed of Chamaecrista fasciculata, an annual native to the prairies of North America, from four locations along a latitudinal gradient. We generated inter‐ and intrapopulation crosses and grew them in two common gardens located in restored prairies in southeast Minnesota. We found that northern populations tended to flower and fruit earlier than southern populations, while hybrids generally had intermediate phenologies. There were strong fitness benefits of hybridization, particularly among the local crosses. However, the plants grown from our southernmost seed source produced few mature seed pods in the common gardens before the advent of fall frost, suggesting that translocating populations across significant latitudinal distances may be problematic. Taken together, our findings support a regional admixture provenancing approach while indicating that assisted migration and assisted gene flow across latitudinal distances of three degrees or more compromises fitness in this species.

Planispiral Valvatids (Mollusca: Gastropoda: Valvatidae) of Subgenus &lt;i&gt;Sibirovalvata &lt;/i&gt;in Upper Ob Basin

In reservoirs and watercourses of the Upper Ob basin (south of Western Siberia) two representatives of the family Valvatidae (Valvatidae) of the subgenus Sibirovalvata, having a planispiral shell, have been noted. It is shown that two species of planispiral mollusks from this subgenus live in the region: Valvata (Sibirovalvata) frigida and V. (S.) sibirica. On the material from the Upper Ob basin, significant conchological differences between V. (S.) frigida and V. (S.) sibirica by key morphometric indices. According to the results of comparison with the material from the north of Western Siberia, it was found that the shells of the northern (basin of the Taz River) and southern (basin of the Upper Ob) populations of V. (S.) frigida and V. (S.) sibirica differ very slightly in morphometric indices, which indicates a slight variability of these traits within the range. At the same time, the detected significant differences between the northern and southern populations in the absolute size of the shell can presumably be explained by the conditions of specific habitats. At the same time, a more favorable temperature regime in the south may be offset by a lack of oxygen, including during the summer-autumn low water period.

Dispersal capacities of pollen, seeds and spores: insights from comparative analyses of spatial genetic structures in bryophytes and spermatophytes.

The dramatic fluctuations of climate conditions since the late Tertiary era have resulted in major species range shifts. These movements were conditioned by geographic barriers and species dispersal capacities. In land plants, gene flow occurs through the movement of male gametes (sperm cells, pollen grains), which carry nDNA, and diaspores (spores, seeds), which carry both cpDNA and nDNA, making them an ideal model to compare the imprints of past climate change on the spatial genetic structures of different genomic compartments. Based on a meta-analysis of cpDNA and nDNA sequence data in western Europe, we test the hypotheses that nDNA genetic structures are similar in bryophytes and spermatophytes due to the similar size of spores and pollen grains, whereas genetic structures derived from the analysis of cpDNA are significantly stronger in spermatophytes than in bryophytes due to the substantially larger size of seeds as compared to spores. Sequence data at 1-4 loci were retrieved for 11 bryophyte and 17 spermatophyte species across their entire European range. Genetic structures between and within southern and northern populations were analyzed through F and N statistics and Mantel tests. Gst and Nst between southern and northern Europe derived from cpDNA were significantly higher, and the proportion of significant tests was higher in spermatophytes than in bryophytes. This suggests that in the latter, migrations across mountain ranges were sufficient to maintain a homogenous allelic structure across Europe, evidencing the minor role played by mountain ranges in bryophyte migrations. With nDNA, patterns of genetic structure did not significantly differ between bryophytes and spermatophytes, in line with the hypothesis that spores and pollen grains exhibit similar dispersal capacities due to their size similarity. Stronger levels of genetic differentiation between southern and northern Europe, and within southern Europe, in spermatophytes than in bryophytes, caused by higher long-distance dispersal capacities of spores as compared to seeds, may account for the strikingly higher levels of endemism in spermatophytes than in bryophytes in the Mediterranean biodiversity hotspot.

Multiscale stability of an intertidal kelp (Postelsia palmaeformis) near its northern range edge through a period of prolonged heatwaves.

Climate change, including gradual changes and extreme weather events, is driving widespread species losses and range shifts. These climatic changes are felt acutely in intertidal ecosystems, where many organisms live close to their thermal limits and experience the extremes of both marine and terrestrial environments. A recent series of multiyear heatwaves in the northeast Pacific Ocean might have impacted species even towards their cooler, northern range edges. Among them, the high intertidal kelp Postelsia palmaeformis has traits that could make it particularly vulnerable to climate change, but it is critically understudied. In 2021 and 2022, we replicated in situ and aerial P. palmaeformis surveys that were conducted originally in 2006 and 2007, in order to assess the state of northern populations following recent heatwaves. Changes in P. palmaeformis distribution, extent, density and morphometrics were assessed between these two time points over three spatial scales, ranging from 250 m grid cells across the entire 167 km study region, to within grid cells and the individual patch. We found evidence consistent with population stability at all three scales: P. palmaeformis remained present in all 250 m grid cells in the study region where it was previously found, and neither the extent within cells nor the patch density changed significantly between time points. However, there was evidence of slight distributional expansion, increased blade lengths and a shift to earlier reproductive timing. We suggest that apparent long-term stability of P. palmaeformis might be attributable to thermal buffering near its northern range edge and from the wave-exposed coastlines it inhabits, which may have decreased the impacts of heatwaves. Our results highlight the importance of multiscale assessments when examining changes within species and populations, in addition to the importance of dispersal capability and local conditions in regulating the responses of species to climate change.

Maturation of flounder species in the northern part of the Sea of Okhotsk in 1997–2019

Data on the rate of maturation during the linear growth of flounder species in the northern part of the Sea of Okhotsk based on samples collected in 1997–2019 are given. These data contradict the idea developed in the literature about the flounders of the northern part of the Sea of Okhotsk as small-sized, early maturating species. The flounders reach sexual maturity when they reach approximately the same size and age as in northern populations of the same species. In comparison with the populations of the corresponding species in the south of the range, all of them are characterized by relatively late and long maturation, and become fully mature shortly before the end of their life cycle.

Revealing biogeographic patterns in genetic diversity of native and invasive plants and their association with soil community diversity in the Chinese coast

Within‐species genetic diversity is shaped by multiple evolutionary forces within the confines of geography, and has cascading effects on the biodiversity of other taxa and levels. Invasive species are often initially limited in genetic diversity but still respond rapidly to their new range, possibly through ‘pre‐adapted' genotypes or multiple sources of genetic diversity, but little is known about how their genetic structure differs from that of native species and how it alters the genetic‐species diversity relationship. Here, we selected a widespread native species Phragmites australis and its co‐occurring invasive competitor Spartina alterniflora as our model plant species. We investigated the genetic structure of P. australis using two chloroplast fragments and ten nuclear microsatellites in 13 populations along the Chinese coastal wetlands. We discovered a distinct geographical differentiation, showing that the northern and southern populations harbored unique genotypes. We also found a significant increase in genetic diversity (allelic richness and expected heterozygosity) from south to north. Combined with previous studies of S. alterniflora, the Mantel tests revealed a significant correlation of genetic distances between P. australis and S. alterniflora even when controlling for geographic distance, suggesting that the invasive species S. alterniflora might exhibit a phylogeographic pattern similar to that of the native species to some extent. Furthermore, our results suggest that the S. alterniflora invasion has altered the relationship between the genetic diversity of the dominant native plant and the associated species richness of soil nematodes. The reason for the alteration of genetic‐species diversity relationship might be that the biological invasion weakens the environmental impact on both levels of biodiversity. Our findings contribute to understanding the latitudinal patterns of intraspecific genetic diversity in widespread species. This work on the genetic diversity analysis of native species also provides significant implications for the invasion stage and ecological consequences of biological invasions.

Postglacial phylogeography, admixture, and evolution of red spruce (Picea rubens Sarg.) in Eastern North America.

Climate change is a major evolutionary force that can affect the structure of forest ecosystems worldwide. Red spruce (Picea rubens Sarg.) has recently faced a considerable decline in the Southern Appalachians due to rapid environmental change, which includes historical land use, and atmospheric pollution. In the northern part of its range, red spruce is sympatric with closely related black spruce (Picea mariana (Mill.) B.S.P.), where introgressive hybridization commonly occurs. We investigated range-wide population genetic diversity and structure and inferred postglacial migration patterns and evolution of red spruce using nuclear microsatellites. Moderate genetic diversity and differentiation were observed in red spruce. Genetic distance, maximum likelihood and Bayesian analyses identified two distinct population clusters: southern glacial populations, and the evolutionarily younger northern populations. Approximate Bayesian computation suggests that patterns of admixture are the result of divergence of red spruce and black spruce from a common ancestor and then introgressive hybridization during post-glacial migration. Genetic diversity, effective population size (Ne) and genetic differentiation were higher in the northern than in the southern populations. Our results along with previously available fossil data suggest that Picea rubens and Picea mariana occupied separate southern refugia during the last glaciation. After initial expansion in the early Holocene, these two species faced a period of recession and formed a secondary coastal refugium, where introgressive hybridization occurred, and then both species migrated northward. As a result, various levels of black spruce alleles are present in the sympatric red spruce populations. Allopatric populations of P. rubens and P. mariana have many species-specific alleles and much fewer alleles from common ancestry. The pure southern red spruce populations may become critically endangered under projected climate change conditions as their ecological niche may disappear.

A range‐expanding butterfly is susceptible to cold and long winters but shows no signs of local adaptation to winter conditions

Abstract Numerous species shift or expand their ranges poleward in response to climate change. Even when expanding species follow their climatic niches, expanding range margin populations are likely to face unfamiliar environmental conditions and thus natural selection for local adaptation. The wall brown butterfly (Lasiommata megera) has expanded northward in Sweden in the years 2000–2020, most likely as a result of climate change, and has previously been shown to have evolved local adaptations to northern daylength conditions. This evolution has occurred despite hypothesised genetic constraints to adaptation at range margins. We studied local adaptation to winter conditions in four of the previously‐studied L. megera populations, using a common garden laboratory experiment with a warm and short, an intermediate, and a cold and long winter treatment. We compared the winter and post‐winter survival of caterpillars from two southern core range and two northern range margin populations in Sweden. During the experiment, we measured metabolic rates of a subset of diapausing caterpillars to test whether populations differ in metabolic suppression during diapause. Further, we measured supercooling points, which reflect lower lethal temperature in L. megera, of the same subset of caterpillars. We also compared supercooling points between L. megera and three closely related species with more northern distributions. Few individuals survived the coldest treatment all the way to successful adult emergence, so L. megera seems susceptible to cold winters. Individuals of northern descent did not survive cold winters any better than individuals from southern populations. Similarly, there were no signs of local adaptation in metabolic rates or supercooling points. The comparison among species did not reveal any clear relationship between geographical distribution and supercooling point. Although northern winters probably exert strong selection on L. megera, we provide comprehensive evidence for the lack of local adaptation to winter conditions. This contrasts with the previous finding of quickly evolved local adaptation in diapause timing, highlighting the need to consider how traits associated with different seasons differ in how they may evolve and facilitate climate change‐induced range expansions. Read the free Plain Language Summary for this article on the Journal blog.

Avoiding mortality: timing prescribed burns in ornate box turtle habitat

AbstractFire is a vital management tool for maintaining prairie ecosystems. Prescribed burns control invasive species, regulate succession, stimulate plant growth, and are a cheap and effective method for removing excess biomass; however, fire can also inadvertently cause wildlife mortality, placing land managers in a challenging situation. Turtles are especially at risk of mortality from fire because of their low mobility and population sensitivity to reductions in adult survival. We studied ornate box turtles (Terrapene ornata) at 3 sites in Illinois, USA, from 2019–2022 to determine the best predictors of above‐ground activity so land managers can conduct prescribed burns when turtles are underground. We used turtle shell temperature, air temperature, soil temperature, and precipitation data to develop a predictive model of above‐ground activity. The best model for predicting above‐ground activity included an interaction between day of year and current air temperature. Earlier in spring and later in fall, above‐ground activity is more likely at higher air temperatures compared to later in spring and earlier in fall when the same likelihood of above‐ground activity is predicted at lower air temperatures. In spring, we recommend burning in Illinois ornate box turtle habitat before 1 April when air temperature is &lt;10°C and in fall after 1 November when air temperature is &lt;15°C. Above these temperature thresholds, there is a &gt;5% likelihood that turtles in northern populations are above ground.

A compilation of common crossbill Loxia curvirostraL., 1758 ring-recovery data from the Iberian Peninsula and other European regions

In November 2021, a female common crossbill ringed in Switzerland was found in the Sistema Central mountain range, within the administrative border of the Community of Madrid (Spain). This is an unusal record due to the lack of data on irruptions of this species from central or northern Europe in the centre of the Iberian Peninsula. In this study, we have compiled all the existing common crossbill ring-recovery data from Iberia and other European regions. Our results show that common crossbill populations in the Iberian Peninsula are mainly sedentary, with limited movements across the different pine forest masses in search of food. In contrast, northern European common crossbill populations develop long distance migratory movements that may involve a large number of individuals following a NE-SW axis that, in an irregular manner and depending on the year, can arrive in the Iberian Peninsula in mid-August or September, where they may remain for several years before returning to their places of origin. In the Iberian Peninsula, these crossbills seem to use the pine species available as a trophic resource according to their ecological speciation, including species not present in their regions of origin.