Journals
2025 EN
Despard Brecia A. · Selwyn Jason D. · Shupp Allison N.
+1 more
ABSTRACT Coral reefs are increasingly threatened by disease outbreaks, yet little is known about the genetic mechanisms underlying disease resistance. Since the 1970s, White Band Disease (WBD) has decimated the Caribbean staghorn coral Acropora cervicornis . However, 15% or more of individuals are highly disease‐resistant, and the genes controlling the production of Argonaut proteins, involved in microRNA (miRNA) post‐transcriptional gene silencing, are up‐regulated in WBD‐resistant corals. This suggests that miRNAs may be key regulators of coral immunity. In this study, we conducted an in situ disease transmission experiment with five healthy‐exposed control tanks and five WBD‐exposed tanks, each containing 50 A. cervicornis genotypes, sampled over 7 days and then sequenced miRNAs from 12 replicate genotypes, including 12 WBD‐exposed and 12 healthy‐exposed control fragments from two time points. We identified 67 bona fide miRNAs in A. cervicornis , 3 of which are differentially expressed in disease‐resistant corals. We performed a phylogenetic comparison of miRNAs across cnidarians and found greater conservation of miRNAs in more closely related taxa, including all three differentially expressed miRNAs being conserved in more than one Acropora coral. One of the three miRNAs has putative genomic targets involved in the cnidarian innate immunity. In addition, community detection coupled with over‐representation analysis of our miRNA–messenger RNA (mRNA) target network found two key unique A. cervicornis miRNAs regulating multiple important immune‐related pathways such as Toll‐like receptor pathway, endocytosis, and apoptosis. These findings highlight how multiple miRNAs may help the coral host maintain immune homeostasis in the presence of environmental stress including disease.
Journals
2025 EN
McGee Kathryn · Perlut Noah G. · Travis Steven E.
ABSTRACT Microsatellite loci in non‐coding regions of nuclear DNA provide an important tool for genetic diversity research, particularly when comparing relatedness between individuals. While microsatellites have been developed for several species within the Blackbird family ( Icteridae ), no species‐specific microsatellite primers for genetic analysis of Bobolinks ( Dolichonyx oryzivorus ) exist. Like many grassland songbirds, Bobolink populations are in decline, and accessible genetic analysis tools are therefore critical for understanding population dynamics. This paper introduces ten new, polymorphic microsatellite loci, at least eight of which should provide a reliable tool for the future study and monitoring of Bobolink genetics. These hypervariable and thus highly informative loci were amplified in 152 adult individuals from a well‐studied population in Shelburne, Vermont, USA.
Journals
2025 EN
Carlyle Cody G. · Roth James D. · Young Brent G.
+3 more
ABSTRACT Anthropogenic climate warming is triggering poleward species redistributions, highlighting the importance of understanding how species distributions and abundance vary along latitudinal gradients. Ringed seals ( Pusa hispida ) rely on sea ice as habitat during key periods of their life history and inhabit a broad latitudinal range with diverse sea‐ice conditions, making them a model species to study patterns in density along a spatial–environmental gradient. We estimated the density of ringed seals from systematic aerial surveys along a latitudinal gradient in the eastern Canadian Arctic to investigate the response of ringed seals to regional variation in sea‐ice conditions. Ringed seals exhibited similar densities at our low (58.8° N; 2017: 0.46 ± 0.11 seals/km 2 ) and intermediate latitude (72.7° N; 2016: 0.70 ± 0.14 seals/km 2 ; 2017: 0.45 ± 0.07 seals/km 2 ) regions. In contrast, observed ringed seal densities (2018: 0.05 ± 0.01 seals/km 2 ; 2019: 0.09 ± 0.01 seals/km 2 ) in the high‐latitude region (82.5° N) were an order of magnitude lower. This shift is concurrent with the transition in ice conditions from predominantly first‐year ice (85.0% concentration) at the low‐latitude region to primarily multiyear ice (86.8% concentration) at the high‐latitude region. These findings indicate that the variation in icescapes across the ringed seal's vast range likely has an influence on their density. We propose that ringed seal densities at higher latitudes are limited by multiyear ice, which is less suitable for construction of undersnow lairs and breathing holes. The shift in sea‐ice conditions may also have consequences for biological productivity that supports their diet. Our results suggest a nonuniform response of ringed seals to ongoing sea‐ice recession across the Arctic. Ringed seal densities could increase with a shift from multiyear to first‐year ice at higher latitudes and simultaneously decline with a transition from first‐year ice to open water at lower latitudes.
Journals
2025 EN
Roberson Briana J. · Perea Santiago · DeRoseBroeckert Daniel
+1 more
ABSTRACT Photoluminescence produced by excitation with ultraviolet light has been documented in an increasing number of nocturnal–crepuscular mammal species. Here, we provide a quantitative analysis to confirm visual observations of UV‐induced photoluminescence in six North American bat species. We used museum specimens to examine wavelength at peak photoluminescent emission, within and among species. We observed green photoluminescence on the wings, uropatagium, and hind limbs of all 60 museum specimens examined. Spectral scans revealed a consistent emission peak between 520 and 552 nm corresponding to the observed green color. We found no differences in wavelength between species or sexes. Wavelength was not related to specimen age, supporting the use of museum specimens for detection of photoluminescence. Our results suggest the potential for photoluminescence to be homologous in origin among the species we examined. We emphasize the need for further exploration into potential evolutionary and functional roles of photoluminescence across mammalian taxa.
Journals
2025 EN
Gerhardy Saskia P. · Delean Steven · Olds Liberty G. M.
+1 more
ABSTRACT Periphery populations can use habitat that differs significantly from core populations, as these regions often represent altered ecological pressures and resource availability. We assess the habitat use of the endangered Plains‐wanderer ( Pedionomus torquatus ), a ground‐dwelling bird, in the periphery of the species' known distribution. Grasslands are key habitats in the species' core range, but these habitats are largely absent at the periphery of their range. Between 2022 and 2024, 29 Plains‐wanderers were tracked using VHF and GPS loggers to measure fine‐scale habitat use in the western range periphery. Plains‐wanderers used habitat primarily dominated by Sclerolaena species, averaging 55% of total cover and 11 cm in height, and the remainder was composed of 40% bare ground and 5% litter. The Sclerolaena ‐dominated vegetation community used by Plains‐wanderers differed in overall composition compared to preferred habitat in the eastern core range, particularly in the absence of grasses, while the general habitat height structure and minimum required open ground remained similar to the core. This study identifies a novel vegetation association for the species, thereby extending the area of potential occupation to include a variety of open‐plains vegetation associations at the range edge. Our findings show that periphery populations of Plains‐wanderers exhibit greater ecological flexibility in habitat selection than previously recognised. As such, the long‐held notion that Plains‐wanderers are exclusively ‘grassland specialists’ should be broadened to incorporate the suitability of low forb‐like Chenopod shrublands. Localised studies of individual animal movement reveal the vegetation characteristics critical to the persistence of this threatened species at the edge of their range.
Journals
2025 EN
MehlhausenFranks Robin S. · Portugal Steven J.
ABSTRACT With the global rapid expansion of urban and developed areas, an understanding of how species adapt behaviourally and physiologically to changing environments is of ever‐increasing importance. Anthropogenic land development is of particular significance to species that traverse long distances in groups, such as migratory birds. Despite the high energetic cost of powered flight, there has been little research into how bird species adapt their flight patterns in response to changes in topography. Notably, there remains a gap in our understanding of how terrain cover impacts the energetic cost of flight. We examined several parameters describing flight and flock behaviours in three cluster flocks of homing pigeons ( Columba livia d .), including flap frequency as a proxy for energy expenditure. Each flock was flown repeatedly over a heterogeneous landscape of open, wooded, and urban habitats. We found that the birds adopted significantly slower flight and less dense flocking behaviour when traversing over woodland, while flying significantly faster with a lower flap frequency over urban areas. The causes of these trends are not immediately clear, and we discuss a range of potential explanations, including the influence habitat has on the wariness of individuals and the significance of landmarks and visual noise in aerial navigation.
Journals
2025 EN
Hu Juntao · Ren Xingyue · Barrett Rowan D. H.
+3 more
ABSTRACT Phenotypic variation is common across life history and among populations occupying different environments, yet the molecular mechanisms underlying these axes of divergence remain poorly understood. Much work has focused on gene expression as a link between genetic variation, environmental variation, and phenotypes, but post‐transcriptional processes such as alternative splicing—which affect how transcripts are assembled rather than how much of a transcript is produced—are increasingly recognized as additional modulators of plasticity and adaptation. Here, we examined gene expression and alternative splicing together in the wood frog ( Rana sylvatica ), an amphibian with a complex life cycle whose populations differ across replicated gradients of road adjacency and associated pollution. We found extensive transcriptomic differences between hatchlings and adults, with thousands of genes differentially expressed or spliced. Individuals clustered strongly by population for both expression and splicing. Differences at the habitat level were less extensive, but revealed two differentially expressed genes ( HSP70 and Gpsm2 ) and one differentially spliced gene ( Cd82 ) that consistently distinguished roadside and woodland populations. Overall, genetic differentiation between populations was low, suggesting that phenotypic and transcriptomic differences likely emerge in the presence of gene flow and reflect plastic responses. Together, these results highlight transcriptomic plasticity as an important mechanism shaping variation across both development and population differentiation.
Journals
2025 EN
Thompson Samuel G. · Portugal Steven J.
ABSTRACT Many prey species defend themselves against predators by sequestering toxins, which they advertise using conspicuous warning signals—a survival strategy termed ‘aposematism’. It is common for predators to avoid attacking aposematic prey for this reason, however, neophobia towards novel prey items may also play a part in this decision. In this study, we deployed green (cryptic‐morph) and black‐and‐yellow (aposematic‐morph) pastry caterpillar models at a study site in the UK. All models were initially palatable; however black‐and‐yellow models were manipulated with quinine in later trials to be distasteful. When both model colours were palatable, predation increased steadily but neither model type showed a survival advantage over the other. In later trials, black‐and‐yellow models defended with quinine experienced lower predation rates than palatable green models. Predator foraging strategies and implications for the effectiveness of aposematism as a survival strategy are discussed. Other potential explainers for the predation rates observed, such as dietary conservatism and the arrival of juveniles, are also highlighted.
Journals
2025 EN
DeRoseBroeckert Daniel R. · Hammond Billy R. · Castleberry Steven B.
+1 more
ABSTRACT Ultraviolet (UV) induced photoluminescence is widespread in Mammalia; however, its function(s) remain unclear. Most of the research to date has focused on the surface expression of photoluminescence (e.g., pelage), described qualitatively. Here, we report a quantitative assessment of photoluminescence of white‐tailed deer ( Odocoileus virginianus , herein deer) used for marking signposts. We analyzed 146 signposts, including 109 antler rubs on trees and 37 scent‐marking scrapes. We compared the spectra of signposts to the spectra of surrounding environmental features elicited by exposure to excitation lights peaking at 365 and 395 nm. Signposts showed significant contrast when compared to environmental backgrounds ( p < 0.001), and the resulting photoluminescence would be visible to deer based on previously described deer visual capabilities. This research is the first quantitative description of the functional use of environmental photoluminescence by a mammal and gives new perspective about how white‐tailed deer perceive their environment and communicate.
Journals
2025 EN
Nimbs Matt J. · Byrne Maria · Dalton Steven J.
+5 more
ABSTRACT Understanding the dynamics of range expanding species, particularly those that have effects on recipient reefs, is vital to inform management and conservation strategies. A rare outbreak of the tropical Crown of Thorns seastar ( Acanthaster cf. solaris ) (COTS) on a subtropical coral reef and a subsequent control program, presented the opportunity to determine the likely origins and number of recruitment events that may have generated this outbreak. The presence of both cosmopolitan and regional mitochondrial haplotypes in this outbreak population indicated larval connectivity via the poleward flowing East Australian Current (EAC) from the Great Barrier Reef (GBR) and Coral Sea. High genetic connectivity with the GBR, based on mitochondrial COI variation, where multiple COTS outbreak events have occurred through time, suggests a high risk of future outbreaks in subtropical eastern Australia. Additionally, levels of COI genetic diversity in the subtropical outbreak population are consistent with either ongoing recruitment or multiple source populations, rather than a new founder population from a single dispersal event. Outbreaks of COTS are likely to become a more frequent occurrence under future climate change scenarios as the poleward‐flowing EAC strengthens and brings warmer waters to subtropical reefs. Agencies that manage subtropical reefs should prepare and plan for future outbreak events and develop policy and management strategies for this range extending species.