As an endemic species of the Qinghai–Tibet Plateau, the Plateau Pika (Ochotona curzoniae) exhibits adaptation to the extremely high-altitude environment and possesses a number of distinct physiological characteristics. In order to explore potential mechanisms underlying the adaptation of plateau pikas, we investigate transcriptomic differences across tissues (heart, liver, spleen, lung, kidney, muscle, cerebellum, left brain, and right brain) of the Plateau Pika, in a comparative framework. We analyze possible mechanisms of adaptive evolution by including a transcriptome analysis across the 9 tissues from 3 male and 4 female O. curzoniae and contrasting results with the 8 male and 4 female Gansu Pika (O. cansus) that inhabits the lower middle altitudes. Differential expression and protein–protein interaction network analyses were used to identify the differentially expressed genes and their primary functions. By analyzing interspecific differences, we identified significant adaptive transcriptional changes in the heart, lung, and spleen of the Plateau Pika. Specifically, upregulated genes in these tissues not only show a substantial association with apoptosis and DNA damage repair, but also demonstrate apparent enrichment in biological pathways related to energy metabolism and immune regulation. The majority of downregulated genes exhibit decreased activity in metabolic pathways particularly in muscle, spleen, kidney, and brain tissues. We further reveal the pivotal gene interaction networks of the 9 tissues. Our study provides valuable insight into adaptive mechanisms underlying evolution of Plateau Pika at extreme altitudes.

In the westernmost Canadian province of British Columbia, fishers (Pekania pennanti) occur in low-elevation forested ecosystems in the central and northern portions of the province, with several substantial mountain ranges and rivers bisecting this distribution. The effect of these geographic features on gene flow and population structuring is unknown and may contribute to fishers differentiating into 2 or more populations within the province. To better understand population structuring within the range of fishers in British Columbia, we collected tissue samples from 491 fishers from throughout the province and evaluated variation of neutral genetic markers using a 385-base pair section of the mitochondrial DNA control region and 13 microsatellite loci. Fishers appeared to be genetically structured as hierarchical stepping-stone populations where an upper hierarchical level of genetic partitioning resulted in 2 populations at the provincial scale, with 3 subpopulations occurring in the central interior region. We observed gene flow of 2 to 5 migrants per generation between the 2 upper populations, which was substantially less than the 90 migrants per generation estimated as needed to maintain genetic homogeneity. This resulted in differentiated upper populations (haplotype F_ST = 0.272, microsatellite F_ST = 0.049) characterized by relatively low N_e (Columbian population = 252, 95% CI = 185 to 332; Boreal population [British Columbia only] = 136, 95% CI = 92 to 234). The consequence of low gene flow and resultant population structuring is that the Columbian population likely receives relatively little genetic and demographic support from other populations and, combined with precipitous recent declines in its numbers, puts this population at heightened conservation risk. As a result, swift and effective actions are needed to conserve this vulnerable population of fishers.

Dispersal is an important process that is widely studied across species, and it can be influenced by intrinsic and extrinsic factors. Intrinsic factors commonly assessed include the sex and age of individuals, while landscape features are frequently-tested extrinsic factors. Here, we investigated the effects of both sex and landscape composition and configuration on genetic distances among bare-nosed wombats (Vombatus ursinus)—one of the largest fossorial mammals in the world and subject to habitat fragmentation, threats from disease, and human persecution including culling as an agricultural pest. We analyzed a data set comprising 74 Tasmanian individuals (30 males and 44 females), genotyped for 9,064 single-nucleotide polymorphisms. We tested for sex-biased dispersal and the influence of landscape features on genetic distances including land use, water, vegetation, elevation, and topographic ruggedness. We detected significant female-biased dispersal, which may be related to females donating burrows to their offspring due to the energetic cost of excavation, given their large body sizes. Land use, waterbodies, and elevation appeared to be significant landscape predictors of genetic distance. Land use potentially reflects land clearing and persecution over the last 200 years. If our findings based on a limited sample size are valid, retention and restoration of nonanthropogenic landscapes in which wombats can move and burrow may be important for gene flow and maintenance of genetic diversity.

Among polar bears (Ursus maritimus), only parturient females den for extended periods, emerging from maternal dens in spring after having substantially depleted their energy reserves during a fast that can exceed 8 months. Although den emergence coincides with a period of increasing prey availability, polar bears typically do not depart immediately to hunt, but instead remain at the den for up to a month. This delay suggests that there are likely adaptive advantages to remaining at the den between emergence and departure, but the influence of the timing and duration of this post-emergence period on cub survival has not been evaluated previously. We used temperature and location data from 70 denning bears collared within the Southern Beaufort Sea and Chukchi Sea subpopulations to estimate the phenology of the post-emergence period. We evaluated the influence of various spatial and temporal features on duration of the post-emergence period and evaluated the potential influence of post-emergence duration on litter survival early in the spring following denning. For dens that likely contained viable cubs at emergence (n = 56), mean den emergence occurred on 16 March (SE = 1.4 days) and mean departure on 24 March (SE = 1.6 days), with dates typically occurring later in the Chukchi Sea relative to Southern Beaufort Sea and on land relative to sea ice. Mean duration of the post-emergence period was 7.9 days (SE = 1.4) for bears that were observed with cubs later in the spring, which was over 4 times longer than duration of those observed without cubs (1.9 days). Litter survival in the spring following denning (n = 31 dens) increased from 0.5 to 0.9 when duration of the post-emergence period increased by ∼4 days and other variables were held at mean values. Our limited sample size and inability to verify cub presence at emergence suggests that future research is merited to improve our understanding of this relationship. Nonetheless, our results highlight the importance of the post-emergence period in contributing to reproductive success and can assist managers in developing conservation and mitigation strategies in denning areas, which will be increasingly important as human activities expand in the Arctic.

Within African savannas, seasonal rainfall influences the survival of mammalian grazers by determining the availability and quality of food. The strength of these effects may, however, vary depending on the availability of reserve and buffer resources within the home range of an individual. From 1999 to 2019, 24% of the white rhino (Ceratotherium simum simum) calves born in Ithala Game Reserve died without a known cause. To explore this, we investigated the impacts of seasonal rainfall on calf survival, and whether these relationships were modified by the availability of woodlands (i.e., reserve resources) and bunch grasslands (i.e., buffer resources) within the home ranges established by the mothers. We found that nearly all of the deceased calves died during their first dry season after weaning had commenced. The likelihood of a calf surviving this period was positively influenced by rainfall during the dry season and negatively influenced by its duration. However, these effects were more pronounced when the availability of woodlands within the home range of the mother was high. Ultimately, calf deaths were caused by a combination of low dry season rainfall, long dry seasons, and the selection of home ranges with insufficient bunch grasslands by some mothers. With climate change models predicting increased dry season durations and a reduction in dry season rainfall, our results highlight future challenges for the conservation of white rhinos and other large herbivores.

Shifts in mean body size coinciding with environmental change are well documented across animal species and populations, serving as a widespread and complex indicator of climate-change response. In mammal research, identifying and disentangling the potential drivers of these trends (e.g., thermoregulation, resource availability) is hindered by treating adult size as fixed, ignoring morphological changes that occur throughout life in many species. However, observed population-level size trends may reflect underlying shifts in age structure (i.e., change in the proportion of older, potentially larger individuals in the population). Here, we assessed the role of age structure by explicitly evaluating age as a contributor to temporal variation in skull size (a proxy for body size) in 2 carnivorans, Canadian Lynx (Lynx canadensis) and American Marten (Martes americana). Using a series of linear and nonlinear models, we tested age in years (determined by cementum-layer analysis) as a predictor of skull size alongside other factors previously proposed to be important drivers of body-size trends, including population density for lynx and growing season conditions for martens. In both species, age was a significant predictor of skull size indicating a rapid year-to-year increase in young adult size that diminished in later adulthood. However, temporal shifts in age structure alone did not explain the observed changes in size over time, indicating that age structure acts in concert with other as-yet unidentified factors to drive body-size change. By explicitly evaluating the role of age, we can both refine models of temporal body-size trends and gain insights into size change as a signal of underlying demographic shifts—such as age-specific survivorship—providing a more holistic understanding of how mammals are responding to climate change.

Understanding the trophic structure of species assemblages is crucial in order to comprehend how syntropic species coexist in space and time. Bats are the second most taxonomically diverse group of mammals and display a wide range of dietary strategies. Due to their ability to disperse over water, ca. 60% of all extant bat species occur on islands and for the most part their interspecific ecological interactions are poorly known. Using DNA metabarcoding, this study offers the first insights into the diet of Macaronesian bats by providing a holistic overview of prey consumed by all 3 bat species found on Madeira Island (Pipistrellus maderensis, Nyctalus leisleri verrucosus, and Plecotus austriacus) and investigating both interspecific (between P. maderensis and N. l. verrucosus) and intraspecific (between female and male N. l. verrucosus) dietary differences. We identified a total of 110 species of arthropod prey in the diet of the 3 bat species, including multiple agriculture and forestry pest species, a human disease-relevant species, and numerous taxa not previously recorded on the island. Lepidoptera was the primary prey order for all 3 bat species. The diet composition of P. maderensis and N. l. verrucosus differed significantly, with P. maderensis consuming more Diptera and multiple prey taxa not found in the diet of N. l. verucosus. Moreover, male N. l. verrucosus exhibited a broader niche breadth than females. This study is among the first to use DNA metabarcoding to evaluate the diet of insular bats and thus greatly advances knowledge regarding the trophic ecology and pest suppression services of these poorly-known mammals.

Cryptic biodiversity continues to be revealed worldwide, even in apparently well-known groups such as carnivorans. The Neotropical Otter (Lontra longicaudis) presents shape variation in its nose pad, a character that has been used to differentiate species in this group. Based on this, 3 subspecies are recognized: L. l. annectens (Mexico, Central America, and South America west of the Andes), L. l. enudris (Amazon and Orinoco basins), and L. l. longicaudis (Paraná basin and remaining distribution). Previous studies partially supported their distinctness based on mitochondrial DNA markers, morphometrics, and ecological niche modeling. We analyzed genome-wide nuclear markers (ultraconserved elements) of 29 L. longicaudis individuals across the species' range to assess its population structure. Phylogenomic analysis recovered L. longicaudis as paraphyletic with robust support, with 1 clade comprising samples from Mexico and Colombia (trans-Andean populations) and another encompassing the remaining samples (cis-Andean populations), which grouped with 2 other South American species, L. felina and L. provocax. Principal component and admixture analyses strongly differentiated the 2 main L. longicaudis groups, and distinguished the Amazonian individuals from the remaining cis-Andean samples. Our results support the recognition of trans-Andean populations of L. longicaudis as a distinct otter species, which should be recognized as Lontra annectens.

Uma biodiversidade críptica continua a ser revelada em todo o mundo, mesmo em grupos aparentemente bem conhecidos, como os carnívoros. A lontra neotropical (Lontra longicaudis) apresenta variação de formato em sua almofada nasal, característica esta que tem sido utilizada para diferenciar as espécies de lontra. Com base nisso, três subespécies são reconhecidas: L. l. annectens (México, América Central e América do Sul, a oeste dos Andes), L. l. enudris (bacias dos rios Amazonas e Orinoco) e L. l. longicaudis (bacia do rio Paraná e restante de sua distribuição). Estudos anteriores apoiaram parcialmente a distinção das subespécies com base em marcadores de DNA mitocondrial, morfometria e modelagem de nicho ecológico. Neste estudo, nós analisamos marcadores nucleares ao longo de todo o genoma (elementos ultraconservados) de 29 indivíduos de L. longicaudis, distribuídos por toda a sua distribuição, para avaliar a estruturação populacional desta espécie. A análise filogenômica recuperou, com suporte robusto, L. longicaudis como parafilética, com um clado compreendendo exemplares do México e Colômbia (populações transandinas) e um segundo clado englobando os exemplares cisandinos que se agruparam com outras duas espécies sul-americanas, L. felina e L. provocax. As análises de componentes principais e de mistura genética diferenciaram fortemente os dois principais grupos de L. longicaudis e, além disso, distinguiram os indivíduos amazônicos das demais amostras cis-andinas. Nossos resultados apoiam o reconhecimento das populações transandinas de L. longicaudis como uma espécie distinta de lontra, que deve ser reconhecida como Lontra annectens.

Three species of pocket mice (Chaetodipus artus, C. goldmani, and C. pernix) characterize the Sinaloan subregion of the Sonoran regional desert. They occur primarily in Sinaloan thornscrub and monsoon (dry deciduous) forest biotic communities, both of which have suffered from agricultural conversion. Sinaloan thornscrub occurs along the coastal plains of southern Sonora and Sinaloa, México, and grades into monsoon forest in the foothills of the Sierra Madre Occidental. We describe the geographical and ecological distributions of the 3 species of Chaetodipus, evaluate evolutionary relationships within each species based on mitochondrial DNA sequence data, and compare these to previously described phenetic, allozymic, and chromosomal variation. We elevate the subspecies of C. pernix to full species, delineate evolutionary units within C. goldmani and C. artus that we formally recognize as subspecies, and evaluate the conservation status of all 3 species of Chaetodipus.

Tres especies de ratones de abazones (Chaetodipus artus, C. goldmani, y C. pernix) se caracterizan de la subregión Sinaloense perteneciente al desierto de Sonora. Se encuentran principalmente en matorrales espinosos y selvas bajas de Sinaloa, los que han tenido de la reconversión agraria. El matorral espinoso de Sinaloa se encuentra a lo largo de las llanuras costeras del sur de Sonora y Sinaloa, México, transformándose en selva baja caducifolia en las faldas de la Sierra Madre Occidental. Caracterizamos las distribuciones geográficas y ecológicas de las tres especies de Chaetodipus, evaluamos las relaciones evolutivas dentro de cada especie con base en secuencias de ADN mitocondrial y las comparamos con la variación fenética, allozímica, y cromosómica descrita en estudios previos. Elevamos las subespecies de C. pernix a especies completas, delineamos unidades evolutivas dentro de C. goldmani y C. artus que reconocemos formalmente como subespecies, y evaluamos el estado de conservación de las tres especies de Chaetodipus.

Bats from the genus Vampyressa Thomas, 1900 are known from a relatively small number of individuals in Mexico. Through recent collecting efforts in southwestern Mexico, we detected several previously unknown populations of Vampyressa, which appeared to represent a lineage independent from but closely related to V. thyone. Here, we describe this lineage as a new species of the genus Vampyressa from the Mexican states of Guerrero and Oaxaca. The new species is currently known from at least 8 collected specimens and 3 released individuals from 8 localities, and can be differentiated from V. pusilla and V. thyone based on pelage and skull characters, size, mitochondrial Cytochrome b, and nuclear Recombination-activating gene 2 sequence data. The new species has been captured mainly in the lowlands but occurs along a wide altitudinal range from 150 to 2,200 m above sea level. Most of the records of the new species are from west of the Isthmus of Tehuantepec, which evidences a new case of a phylogenetic break at this biogeographic barrier. The genus Vampyressa now includes 6 species, and Mexico expands its position as the country with the largest number of endemic bats in the Neotropics, totaling 20 endemics.

Los murciélagos Vampyressa Thomas, 1900 son conocidos por un número relativamente pequeño de individuos en México. Por medio de recientes esfuerzos de colecta en el suroeste de México detectamos varias poblaciones de Vampyressa previamente desconocidas que parecían representar un linaje independiente pero estrechamente relacionado a V. thyone. En este trabajo, describimos dicho linaje como una nueva especie del género Vampyressa para los estados mexicanos de Guerrero y Oaxaca. Actualmente esta nueva especie es conocida por al menos 8 ejemplares colectados y 3 individuos liberados de 8 localidades, y se puede diferenciar de V. pusilla y V. thyone por los caracteres del pelaje y del cráneo, por el tamaño y por las secuencias del gen mitocondrial citocromo b y del gen nuclear activador de la recombinación 2. La nueva especie ha sido capturada principalmente en tierras bajas, pero se distribuye a lo largo de un amplio rango altitudinal, de 150 a 2,200 metros sobre el nivel del mar. La mayoría de los registros de la nueva especie se encuentran al oeste del Istmo de Tehuantepec, lo que evidencia un nuevo caso de ruptura filogenética en esta barrera biogeográfica. El género Vampyressa ahora incluye 6 especies y México amplía así su posición como el país con la mayor cantidad de murciélagos endémicos del neotrópico, totalizando 20 especies endémicas.

Several issues regarding the systematics and taxonomy of the Neotropical deer tribe Odocoileini, an assemblage of 18 recognized living species currently allocated into 7 genera, remain unclear. The few available phylogenetic analyses indicate that some genera are not monophyletic and that species richness in the group is underestimated. One genus that presents both problems are the stocky and short-legged dwarf deer, Pudu. As currently understood, it includes 2 species, the Northern pudu, Pudu mephistophiles from Peru, Ecuador, and Colombia; and the Southern pudu, P. puda, from southern Chile and nearby Argentina. Here, by means of qualitative and quantitative morphologic analysis and the assessment of genetic variation, we showed that 2 distinct species are encompassed by the current concept of P. mephistophiles. The typical form distributes north of the Huancabamba Depression from northernmost Peru to the north (Ecuador and Colombia), while the other distributes south of the Huancabamba Depression and is a Peruvian endemic. As no name is available for the last one, we describe and name it here. This is the first living cervid species described in the 21st century and the first from the New World in over 60 years. Additionally, as the Southern Pudu (the type species of Pudu) is not sister to the 2 northern pudu species, we revalidate the genus Pudella to allocate the latter 2 species.

Distintos aspectos de la sistemática y taxonomía de la tribu de ciervos neotropicales Odocoileini, que incluye un conjunto de 18 especies vivas reconocidas actualmente que se engloban en siete géneros, siguen sin estar resueltos. Los pocos análisis filogenéticos disponibles indican que algunos géneros no son monofiléticos y que la riqueza del grupo esta subestimada. Uno de los géneros que presenta ambos problemas es el género de ciervos pequeños y patas cortas Pudu. Con base en la clasificación actual, éste incluye dos especies, Pudu mephistophiles distribuido en Perú, Ecuador y Colombia y P. puda distribuido en el sur de Chile y áreas cercanas de Argentina. Este estudio mediante análisis morfológicos cualitativo y cuantitativo y la evaluación de la variación genética, muestra que el concepto actual de P. mephistophiles engloba a dos especies distintas. La forma típica se distribuye al norte de la Depresión de Huancabamba desde el extremo norte de Perú hacia el norte (Ecuador y Colombia), mientras que la segunda se distribuye al sur de la Depresión de Huancabamba y es endémica de Perú. Como no hay nombre disponible para esta última, aquí la nominamos y describimos formalmente. Esta es la primera especie viviente de cérvido descrita en el siglo XXI y la primera del Nuevo Mundo en más de 60 años. Además, como el pudú del sur (la especie tipo de Pudu) no es hermano de las dos especies de pudú del norte, revalidamos el género Pudella para colocar a las dos últimas especies.

The monogeneric family Calomyscidae includes the brush-tailed mice, genus Calomyscus, which have a Palearctic distribution ranging from the Hindu Kush Mountains in western Pakistan to the eastern Mediterranean region. Zagros Mountains—stretching from northwest to south of Iran—was assumed for long as the range of a single species, Calomyscus bailwardi; however, recent studies revealed considerable heterogeneities among the geographical populations presumably referring to the persistence of undescribed diversity. One such group from the western Zagros Mountains has recently been recognized as C. behzadi Akbarirad, Dezhman, Aliabadian, Siahsarvie, Shafaeipour, and Mirshamsi, 2021. Using molecular, morphometric, geometric morphometric, and karyotypic data, we examine the divergence of 2 additional groups from western Iran and name these as new species. The first of these species is distributed in the northern Zagros and western Alborz Mountains in northwestern Iran was recovered as the sister species to C. urartensis from the South Caucuses. The second species from a single locality in the central Zagros Mountains was clustered closely with C. grandis from the western Alborz Mountains. Morphologic analyses, karyological features, and genetic distances disentangled these 2 new species from their sister species.

The genus Ctenomys (Rodentia: Hystricomorpha) includes an impressive diversity of species, all of which have evolved in southern South America. The number of recognized species is currently approaching 70. During the last few decades, taxonomic revisions and new field collections have resulted in both the description of new species and the synonymization of others, suggesting that much of the alpha taxonomy of Ctenomys remains unresolved, particularly when considering the vast areas of distribution that are still unsampled. Both phylogeographic patterns and the fossil record suggest that the Andean Cordillera has played a critical role in the diversification of the genus. Building upon recent, intensive field sampling in the Andean and pre-Andean regions of southern Mendoza Province, I integrated molecular and morphological data to evaluate the taxonomic status of populations of Ctenomys in this region. These analyses revealed a taxonomically-diverse Ctenomys assemblage within which here I provide the description for a new species. Available data indicate that this new species is endemic to southern portions of Mendoza Province, a geographic region that represents the confluence of 3 lineages ‘magellanicus,’ ‘maulinus,’ and ‘mendocinus,’ and that it is thus an area of particular importance for the conservation of these rodents.

El género Ctenomys (Rodentia: Hystricomorpha) incluye una impresionante diversidad de especies, las cuales han evolucionado en el sur de América del Sur. El número de especies reconocidas se acerca actualmente a las 70. Durante las últimas décadas, las revisiones taxonómicas y nuevas colecciones de campo han resultado tanto en la descripción de nuevas especies como en la sinonimia de otras, lo que sugiere que gran parte de la taxonomía alfa de Ctenomys sigue sin resolverse, particularmente cuando se consideran las vastas áreas de la distribución que aún no están muestreadas. Tanto los patrones filogeográficos como el registro fósil sugieren que la Cordillera de los Andes ha jugado un papel fundamental en la diversificación del género. Sobre la base de muestreos de campo intensivos recientes en las regiones Andina y pre-Andina del sur de la Provincia de Mendoza, integré datos moleculares y morfológicos para evaluar el estado taxonómico de las poblaciones de Ctenomys en esta región. Estos análisis revelaron un ensamble de Ctenomys taxonómicamente diverso del cual aquí proporciono la descripción de una nueva especie. Los datos disponibles indican que esta nueva especie es endémica del sur de la provincia de Mendoza, región geográfica que representa la confluencia de 3 linajes del género ‘magellanicus,’ ‘maulinus,’ y ‘mendocinus’ y que, por lo tanto, es un área de particular importancia para la conservación de estos roedores.

Home range and home range overlap can be used to describe use of space and movement of wildlife. During the last years, advancements in technology have greatly improved our understanding of animal movement, especially among large herbivores. Wild ungulate abundance and distribution have increased in temperate areas. Moreover, their diseases—including sarcoptic mange in the Iberian Ibex (Capra pyrenaica)—have become a cause of concern for livestock, public health, and wildlife conservation. In this study, we first reviewed existing literature on the home range of species in the genus Capra. We then analyzed data from 52 GPS-GSM-collared Iberian ibexes, of which 33 were healthy and 19 were affected by sarcoptic mange from 3 different populations in the southeastern Iberian Peninsula to analyze: (1) differences in size and characteristics of home ranges obtained by the 3 most commonly used methodologies—minimum convex polygon, kernel density estimation, and Brownian bridges movement models (BBMMs); and (2) the impact of endemic sarcoptic mange on Iberian Ibex home range. The literature review revealed that available information on spatial behavior of Capra spp. was based only on 3 species, including the Iberian Ibex, estimated through a diversity of methods which made it difficult to compare results. We found positive correlations among the different home range estimation methods in the Iberian Ibex, with BBMMs proving to be the most accurate. This study is the first to use BBMMs for estimating home range in this species, and it revealed a marked seasonal behavior in spatial use, although sarcoptic mange smoothed such seasonal pattern. The seasonal overlaps obtained suggest that core areas of the Iberian Ibex change within wider home range areas, which are ecological parameters relevant to identifying key areas for species management and conservation.

Sympatric animals may consume diets of differing breadths as a strategy to reduce competition. Studying patterns of dietary breadth in extinct taxa is difficult because available data are generally limited to morphology. Dental topographic analysis (DTA) is useful for comparing occlusal morphology and allows for examination of dietary adaptations in extinct taxa. What remains unknown is how dental morphology, quantified using DTA, covaries with dietary breadth. The niche variation hypothesis (NVH) posits that taxa with broader ecological niches will be characterized by greater variability in morphology relative to specialized taxa. Therefore, we predict that taxa with greater dietary breadth will have more varied dental morphology compared to specialists as a result of the molar morphology of specialists being under greater genetic control relative to generalists, with specialists requiring teeth specially adapted to efficiently process a smaller range of food sources. We measured curvature, complexity, and relief of the M₂ of 3 pairs of closely related euarchontan mammals (primates and treeshrews), with each taxon within a pair categorized as a generalist or specialist. Our results indicate that generalists do not consistently show greater variability in dental morphology compared to specialists among primates, but that atelids and treeshrews do generally follow the predictions of the NVH, with the caveat that our treeshrew sample is small. This suggests that while dietary specialists may be under greater genetic constraint with respect to their molar topography, a link between dietary breadth and dental form is not clear. Our study demonstrates that variation in dental topography does not necessarily reflect dietary breadth and highlights the fact that it is difficult to categorize even the most specialized primates (i.e. bamboo lemurs) as “dietary specialists.”

Los animales simpátricos pueden consumir dietas de diferentes amplitudes como estrategia para reducir la competición. Es difícil estudiar los patrones de amplitud dietética en taxones extintos debido a que los datos disponibles generalmente están limitados tan sólo a morfología. El análisis topográfico dental (DTA; dental topographic analysis) es útil para comparar morfologías oclusales y permite examinar las adaptaciones dietéticas en taxones extintos. Lo que aún permanece sin saber es cómo la morfología dental, cuantificada con el uso de DTA, covaría con el rango dietético. La hipótesis de variación de nicho (NVH; niche variation hypothesis) plantea que taxones con nichos ecológicos más amplios se caracterizarán por tener una mayor variabilidad morfológica en comparación con taxones más especializados. Por eso, predecimos que los taxones con una mayor amplitud dietética tendrán una morfología dental más variada comparada con especialistas como resultado de que la morfología molar de los especialistas esté bajo mayor control genético que la de los generalistas, dado que los especialistas requieren dientes especialmente adaptados para procesar eficientemente una menor amplitud de alimentos. Medimos la curvatura, la complejidad y el relieve del M2 de tres pares de Euarchontas evolutivamente cercanos (primates y tupayas) y simpátricos, con cada taxón en cada par categorizado como generalista o especialista. Nuestros resultados indican que los generalistas no muestran, consistentemente, mayor variabilidad en la morfología dental en comparación con los especialistas dentro de los primates, aunque los atélidos y las tupayas generalmente sí que siguen las predicciones de la NVH, aunque admitiendo que nuestra muestra de tupayas es pequeña. Esto sugiere que mientras que puede ser que los especialistas dietéticos estén bajo una mayor restricción genética con respecto a su topografía molar, la conexión entre amplitud dietética y forma dental no es clara. Nuestro estudio demuestra que la variación en topografía dental no se refleja necesariamente en amplitud dietética y recalca el hecho de que es difícil categorizar incluso los primates más especializados (por ejemplo, los lémures del bambú) como “especialistas dietéticos.”

Diurnal flight activity in otherwise strictly nocturnal bats has typically been linked to random disturbance from day roosts, an urgent need to balance food shortage caused by adverse weather during nighttime, or the absence of diurnal predators. However, migration may be another reason why bats fly during daylight, at least in some areas. Using community-science data collection, we obtained more than 500 records of over 15,000 bats displaying diurnal flight activity, suggesting that it is relatively common in Central Europe. The vast majority of sightings were of common noctules (Nyctalus noctula), with most records concentrated in spring and autumn. The seasonal dynamics of diurnal flights exactly coincided with migratory periods, and directional movements in autumn—when diurnal activity was most frequent and included highest numbers of observed bats—suggest that the behavior may ultimately be linked to migration ecology. The highest frequency of diurnal flights in autumn coincided with highest body mass in the studied territory, thereby refuting the hypothesis of early roost emergence due to poor body condition or decreased predation risk related to increased maneuverability. A shift from strictly nocturnal to partly diurnal activity may balance increased energetic demands imposed by migration, which is temporally synchronized with periods of cold nights when prey density is limited. Common noctule diurnal activity during the migratory period may be beneficial as they can acquire energy by foraging on daily abundant prey while saving nighttime for long endurance flights—alternatively, they may forage on the way to their migratory destination, thereby saving time. Predation risk from diurnal predators may be significantly decreased by choosing high flight altitudes, as observed particularly during autumn. We suggest that observations on the geographic distribution of diurnally flying noctules may help identify migration corridors.

Shelter is one critical aspect of an animal's habitat, providing refuge from predators and weather, protection for offspring, and aiding in physiological homeostasis. During the day, bats find shelter in roosts—spaces created under tree bark, in tree cavities, or between rocks—after spending the night searching for food. Finding a roost with a microclimate that enables bats to remain in their thermoneutral zone could reduce energetic demands or allow bats to allocate energy to other activities such as reproduction and fighting disease. We aimed to characterize the structural features and microclimate (i.e., temperature) of roosts used by male Little Brown Myotis (Myotis lucifugus) during the summer and determine whether bats select certain characteristics disproportionally to what is available at different spatial scales. During the summers of 2017 and 2018, we radio-tracked 34 male M. lucifugus in Lodgepole Pine-dominated forests. We located at least 1 roost for 20 individuals (average = 2.85 roosts/bat, range = 1 to 6). Although snags were available, most of the roosts were in rock features (86% in rocks, 14% in trees or snags). Male M. lucifugus were more likely to select rock roosts with less canopy closure that were closer to water compared to available roosts on the landscape. They also selected roosts in rock features occurring within larger areas of rock cover that had wider entrances and access to crevices that faced the sky; these roosts also had warmer microclimates relative to other locations available on the landscape. Crevices that allow the bat to bask in the sun and change locations within a roost, minimizing energy needed for active thermoregulation, could be very beneficial for individuals recovering from diseases such as white-nose syndrome. Our work indicates that rock features provide habitat for male M. lucifugus during summer; other studies have shown that bats roost in these features during autumn and winter, further supporting their importance. By protecting these important rock structures, managers can help bats meet their habitat needs throughout the year.

Los refugios son un aspecto crítico del hábitat de un animal, proporcionando protección contra los depredadores y el clima, resguardo a la descendencia, y ayudan en la homeostasis fisiológica. Durante el día, los murciélagos encuentran refugio en dormideros—espacios creados debajo de la corteza de árboles, en las cavidades de los árboles, o entre rocas—después de pasar la noche buscando comida. Encontrar un refugio con un microclima que permita a los murciélagos permanecer en su zona termoneutral podría reducir las demandas energéticas o permitir que los murciélagos asignen energía a otras actividades, como la reproducción y la lucha contra enfermedades. Nuestro objetivo fue caracterizar los atributos estructurales y el microclima (i.e., temperatura) de los dormideros utilizados por los machos de Myotis lucifugus durante el verano y determinar si los murciélagos seleccionan ciertas características desproporcionadamente a lo que está disponible en diferentes escalas espaciales. Durante los veranos de 2017 y 2018, a través de radio-telemetría, seguimos a 34 machos de M. lucifugus en bosques dominados por pinos contorta. Ubicamos al menos un dormidero para 20 individuos (promedio = 2.85 dormideros/murciélago, rango = 1 a 6). Aunque había tocones arbóreos disponibles, la mayoría de los dormideros estaban en rocas (86% en rocas, 14% en árboles o tocones). Los machos de M. lucifugus tenían más probabilidad de seleccionar dormideros en rocas con menos cobertura del dosel que estaban más cerca al agua, en comparación con los dormideros disponibles en el paisaje. También seleccionaron dormideros en rocas que ocurren dentro de áreas más grandes de cubierta rocosa, con entradas más amplias y acceso a grietas expuestas al cielo; estos dormideros también tenían microclimas más cálidos en relación con otras ubicaciones disponibles en el paisaje. Grietas que permitan al murciélago asolearse y cambiar ubicaciones dentro de un dormidero, minimizando la energía necesaria para la termorregulación activa, podrían ser muy beneficiosas para los individuos que están recuperándose de enfermedades como el síndrome de la nariz blanca. Nuestro trabajo indica que las rocas proporcionan hábitat para los machos de M. lucifugus durante el verano; otros estudios han demostrado que los murciélagos se posan en estas rocas durante el otoño y el invierno, lo que respalda aún más su importancia. Al proteger estas importantes estructuras rocosas, los manejadores de recursos naturales pueden ayudar a los murciélagos a satisfacer sus necesidades de hábitat durante todo el año.

The Tricolored Bat is an imperiled species due to white-nose syndrome. There is limited information available on roosting and foraging area use of the species to support planning and management efforts to benefit recovery in the Southeastern United States. Female tricolored bats exit hibernation and allocate energy toward disease recovery, migration, and reproduction. Providing and managing for summer habitat is 1 strategy to promote recovery. We sought to: (1) determine local- and landscape-scale factors that influence female Tricolored Bat roost selection; (2) quantify land cover use in core and overall foraging areas; and (3) define foraging area size and distances traveled by female tricolored bats in Tennessee. Bats in this study roosted in trees of variable sizes, in multiple tree species with large canopy volumes, and almost always roosted in trees with dead leaf foliage suspended in the canopy. Forest plots used by bats had trees averaging 30 cm diameter at breast height, basal areas averaging 27 m²/ha, contained multiple tree species, and comprised around a 50:50 ratio of canopy and subcanopy trees. Bats did not roost in coniferous forest areas and were only located in deciduous and mixed forest areas. Bats foraged near and directly over water, in open areas, and along forest edges. This study increases our knowledge on habitat requirements of the species in a temperate region dominated by unfragmented forests and many large water bodies and serves a baseline for management and efforts to benefit survival, reproduction, and population recovery.

El murciélago tricolor es una especie amenazada por el Síndrome de la nariz blanca. Exíste poca información sobre las áreas de refugio y forrajeo que informen los esfuerzos por la recuperación en los Estados Unidos. Al salir de la hibernación, las hembras deben distribuir su energía entre recuperarse de la enfermedad, migrar y reproducirse. La protección del hábitat veraniego es crítico para promover la recuperación de la especie. Para este trabajo, queríamos (1) determinar los factores locales y de escala del paisaje que influencien la selección de refugios; (2) cuantificar el uso del paisaje en las áreas de forrajeo; y (3) determinar las distancias máximas de los murciélagos en Tennessee. Los murciélagos usaron refugios en árboles de tamaño variable con grandes volúmenes de dosel. El sitio preferido de percha fue entre las hojas muertas aún suspendidas de las copas de los árboles. Las parcelas más utilizadas incluían: árboles con diámetros de 30cm, áreas basales de 27 m2/ha y con gran diversidad de árboles tanto en el dosel como en el subdosel. No se encontraron individuos refugiados en coníferas. Las principales áreas de forrajeo fueron sobre cuerpos de agua, en áreas abiertas y en las zonas de borde. Nuestro estudio amplía el conocimiento del hábitat veraniego en una región dominada por bosques que no están fragmentados, grandes lagos y arroyos. Esta información es clave para informar esfuerzos de manejo forestal y las estrategias de recuperación de la especie.

Individual marking techniques are critical for studying animals, especially in the wild. Current marking methods for bats (Order Chiroptera) have practical limitations and some can cause morbidity. We tested the p-Chip (p-Chip Corp.)—a miniaturized, laser light-activated microtransponder—as a prospective marking technique in a captive research colony of Big Brown Bats (Eptesicus fuscus). We assessed long-term readability and postimplantation effects of p-Chips injected subcutaneously above the second metacarpal (wing; n = 30) and the tibia (leg; n = 13 in both locations). Following implantation (Day 0), p-Chips were scanned with a hand-held ID reader (wand) on postimplantation days (PIDs) 1, 8, 15, 22, 32, 60, 74, 81, 88, 95, and over 1 year later (PID 464). For each trial, we recorded: (1) animal handling time; (2) scan time; (3) number of wand flashes; (4) p-Chip visibility; and (5) overall condition of the bat. Average scan times for p-Chips implanted in both the wing and leg increased over the duration of the study; however, the number of wand flashes decreased, suggesting that efficacy of p-Chip recording increased with user experience. Importantly, over 464 days both the visibility and readability of p-Chips in the wing remained high and superior to tags in the leg, establishing the second metacarpal as the preferred implantation site. Observed morbidity and mortality in captive bats with p-Chips was similar to baseline values for bats without these tags. Because scan efficiency on PID 464 was comparable with earlier days, this indicates that p-Chips implanted in the wing may be suitable as a long-term marking method. Our provisional results suggest that p-Chips are viable for extended field testing to see if they are suitable as an effective alternative to traditional methods to mark bats.

Las técnicas de marcaje individual son fundamentales para el estudio de los animales, especialmente en la naturaleza. Los métodos actuales de marcaje de murciélagos (Chiroptera) tienen limitaciones prácticas y algunos pueden causar morbilidad. Probamos el p-Chip (p-Chip Corp.)—un microtranspondedor miniaturizado activado por luz láser—como técnica de marcaje prospectivo en una colonia en cautiverio de murciélagos morenos (Eptesicus fuscus). Se evaluó la legibilidad a largo plazo y los efectos pos-implantación de los p-Chips inyectados subcutáneamente sobre el segundo metacarpiano (ala; n = 30) y la tibia (pata; n = 13 en ambas localizaciones). Tras la implantación (día 0), se escanearon los p-Chips con un lector de identificación manual (vara) en los días posteriores a la inyección (PID) 1, 8, 15, 22, 32, 60, 74, 81, 88, 95, y más de un año después (PID 464). En cada ensayo se registró: (1) el tiempo total de manipulación del animal; (2) el tiempo de exploración; (3) el número de destellos de proximidad del lector; (4) la visibilidad del p-Chip; y (5) el estado general del murciélago. Los promedios del tiempo de escaneado de los p-Chips implantados tanto en el ala como en la pata aumentaron a lo largo del estudio; sin embargo, el número de destellos del lector disminuyó, lo que sugiere que la eficacia del registro del p-Chip aumentó con la experiencia del usuario. A lo largo de 464 días, tanto la visibilidad como la legibilidad de los p-Chips en el ala siguieron siendo altas y superiores a las de las etiquetas en la pata, lo que estableció el segundo metacarpiano como el lugar preferido de implantación. La morbilidad y mortalidad observadas en murciélagos en cautiverio con p-Chips fue similar a los valores de referencia de los murciélagos sin estas marcas. Dado que la eficacia del escaneado en el PID 464 fue comparable a la de días anteriores, es probable que los p-Chips implantados en el ala sean adecuados como método de marcado a largo plazo. Nuestros resultados provisionales sugieren que los p-Chips son viables para pruebas de campo prolongadas como alternativa prospectiva a los métodos tradicionales de marcaje de murciélagos.