bluuebunny/crossref_metadata_2025_split huggingface dataset:
Incipient sexual isolation in Laupala cerasina: Females discriminate population-level divergence in acoustic characters
Authors: Grace Jaime L. , Shaw Kerry L. 
Published: February 2016

Abstract
Sexual selection by female choice can shape the evolution of male traits within populations, since the most attractive males experience an increase in fitness through elevated mating success. Speciation by sexual selection occurs when evolution in traits and preferences within populations causes differentiation among populations, such that females in alternative populations prefer sexual signals of their own population relative to others. Differentiated traits and preferences thereby play an active role in limiting gene flow between divergent populations. The effectiveness of differentiated preferences in maintaining differentiated male signals against the homogenizing effects of gene flow across populations will be limited by both the degree to which females can discriminate against non-local males, and the breeding values of traits and preferences. Populations of the Hawaiian cricket Laupala cerasina have diverged in pulse rate, a sexually selected male signal, and female acoustic preference for pulse rate. Gene flow between neighboring populations may be reduced if migrants from sexually diverged populations experience reduced mating success. We show that females discriminate among divergent songs characteristic of neighboring populations, that differences among populations in song and preference breed true in a common environment, and that mean preferences for each population closely match the mean pulse rates. Divergence in preference was observed only between populations that also differed in song. Along with a striking ability to discriminate slight differences in song, correlated evolution of song and preference within populations could be a mechanism that promotes assortative mating among populations, thereby reducing gene flow, and leading to speciation in Laupala.
Assessing habitat quality of the mountain nyala Tragelaphus buxtoni in the Bale Mountains, Ethiopia
Authors: Evangelista Paul H. , Norman John , Swartzinki Paul 
Published: February 2016

Abstract
Populations of the endangered mountain nyala Tragelaphus buxtoni are significantly threatened by the loss of critical habitat. Population estimates are tentative, and information on the species’ distribution and available habitat is required for formulating immediate management and conservation strategies. To support management decisions and conservation priorities, we integrated information from a number of small-scale observational studies, interviews and reports from multiple sources to define habitat parameters and create a habitat quality model for mountain nyala in the Bale Mountains. For our analysis, we used the FunConn model, an expertise-based model that considers spatial relationships (i.e., patch size, distance) between the species and vegetation type, topography and disturbance to create a habitat quality surface. The habitat quality model showed that approximately 18,610 km2 (82.7% of our study area) is unsuitable or poor habitat for the mountain nyala, while 2,857 km2 (12.7%) and 1,026 km2 (4.6%) was ranked as good or optimal habitat, respectively. Our results not only reflected human induced habitat degradation, but also revealed an extensive area of intact habitat on the remote slopes of the Bale Mountain’s southern and southeastern escarpments. This study provides an example of the roles that expert knowledge can still play in modern geospatial modeling of wildlife habitat. New geospatial tools, such as the FunConn model, are readily available to wildlife managers and allow them to perform spatial analyses with minimal software, data and training requirements. This approach may be especially useful for species that are obscure to science or when field surveys are not practical.
Choosing between a rock and a hard place: Camouflage in the round-tailed horned lizard Phrynosoma modestum
Authors: Cooper William E. , Sherbrooke Wade C. 
Published: February 2016

Abstract
The round-tailed horned lizard Phrynosoma modestum is cryptically colored and resembles a small stone when it draws legs close to its body and elevates its back. We investigated effectiveness of camouflage in P. modestum and its dependence on stones by placing a lizard in one of two microhabitats (uniform sand or sand with surface rocks approximately the same size as lizards). An observer who knew which microhabitat contained the lizard was asked to locate the lizard visually. Latency to detection was longer and probability of no detection within 60 s was higher for lizards on rock background than on bare sand. In arenas where lizards could choose to occupy rock or bare sand, much higher proportions selected rocky backgrounds throughout the day; at night all lizards slept among stones. A unique posture gives P. modestum a rounded appearance similar to many natural stones. Lizards occasionally adopted the posture, but none did so in response to a nearby experimenter. Stimuli that elicit the posture are unknown. That P. modestum is better camouflaged among rocks than on bare sand and prefers to occupy rocky areas suggests that special resemblance to rocks (masquerade) enhances camouflage attributable to coloration and immobility.
What makes a cry a cry? A review of infant distress vocalizations
Authors: Lingle Susan , Wyman Megan T. , Kotrba Radim , Teichroeb Lisa J. , Romanow Cora A. 
Published: February 2016

Abstract
In contrast to the cries of human infants, sounds made by non-human infants in different stressful behavioral contexts (hunger or physical discomfort, isolation, capture by humans or predators) are usually treated as distinct types of vocalizations. However, if distress vocalizations produced by different species and in different contexts share a common motivational state and associated neurochemical pathways, we can expect them to share a common acoustic structure and adaptive function, showing only limited variation that corresponds to the infant’s level of arousal. Based on this premise, we review the acoustic structure and adaptive function of two types of distress calls, those given when infants were isolated from their mothers (isolation calls) or captured by humans (capture calls). We conducted a within-context comparison examining the two call types across a diverse selection of mammalian species and other vertebrate groups, followed by a comparison of how acoustic structure and function differs between these contexts. In addition, we assessed acoustic traits that are critical to the response of caregivers. Across vertebrate species, distress vocalizations produced in these two behavioral contexts tend to be tonal with a simple chevron, flat or descending pattern of frequency modulation. Reports that both isolation and capture calls of vertebrate infants serve to attract care-givers are universal, and the fundamental frequency of infant vocalizations is often critical to this response. The results of our review are consistent with the hypothesis that differences in the acoustic structure of isolation and capture distress vocalizations reflect differences in arousal, and not discrete functions. The similarity in acoustic structure and caregiver response observed across vertebrates adds support to the hypothesis that the production and processing of distress vocalizations are part of a highly-conserved system of social vocal behaviour in vertebrates. Bioacoustic research may move forward by recognizing the commonality among different forms of infant solicitations that attract caregivers, and the commonality of these solicitations with vocalizations that attract conspecifics in still other behavioral contexts.
Who’s your neighbor? Acoustic cues to individual identity in red squirrel Tamiasciurus hudsonicus rattle calls
Authors: Digweed Shannon M. , Rendall Drew , Imbeau Teana 
Published: February 2016

Abstract
North American red squirrels Tamiasciurus hudsonicus often produce a loud territorial rattle call when conspecifics enter or invade a territory. Previous playback experiments suggest that the territorial rattle call may indicate an invader’s identity as squirrels responded more intensely to calls played from strangers than to calls played from neighbors. This dear-enemy effect is well known in a variety of bird and mammal species and functions to reduce aggressive interactions between known neighbors. However, although previous experiments on red squirrels suggest some form of individual differentiation and thus recognition, detailed acoustic analysis of potential acoustic cues in rattle calls have not been conducted. If calls function to aid in conspecific identification in order to mitigate aggressive territorial interactions, we would expect that individual recognition cues would be acoustically represented. Our work provides a detailed analysis of acoustic cues to identity within rattle calls. A total of 225 calls across 32 individual squirrels from Sheep River Provincial Park, Kananaskis, AB, Canada, were analyzed with discriminant function analysis for potential acoustic cues to individual identity. Initial analysis of all individuals revealed a reliable acoustic differentiation across individuals. A more detailed analysis of clusters of neighboring squirrels was performed and results again indicated a statistically significant likelihood that calls were assigned correctly to specific squirrels (55%-75% correctly assigned); in other words squirrels have distinct voices that should allow for individual identification and discrimination by conspecifics.
Ultraviolet reflection enhances the risk of predation in a vertebrate
Authors: Modarressie Ricarda , Rick Ingolf P. , Bakker Theo C. M. 
Published: February 2016

Abstract
Many animals are sensitive to ultraviolet light and also possess UV-reflective regions on their body surface. Individuals reflecting UV have been shown to be preferred during social interactions such as mate choice or shoaling decisions. However, whether those body UV-reflections enhance also the conspicuousness to UV-sensitive predators and therefore entail costs for its bearer is less well documented. Two size-matched three-spined sticklebacks Gasterosteus aculeatus, one enclosed in a UV-transmitting (UV+) and another in a UV-blocking (UV-) chamber, were simultaneously presented to individual brown trout Salmo trutta. “yearlings”. Brown trout of this age are sensitive to the UV part of the electromagnetic spectrum and are natural predators of three-spined sticklebacks. The stickleback that was attacked first as well as the subsequent number of attacks was recorded. Sticklebacks enclosed in the UV-transmitting chamber were attacked first significantly more often compared to sticklebacks enclosed in the UV-blocking chamber. Control experiments using neutral density filters revealed that this was more likely due to UV having an influence on hue perception rather than brightness discrimination. The difference in attack probability corresponded to the difference in chromatic contrasts between sticklebacks and the experimental background calculated for both the UV+ and UVconditions in a physiological model of trout colour vision. UV reflections seem to be costly by enhancing the risk of predation due to an increased conspicuousness of prey. This is the first study in a vertebrate, to our knowledge, demonstrating direct predation risk due to UV wavelengths.
Using potential distributions to explore environmental correlates of bat species richness in southern Africa: Effects of model selection and taxonomy
Authors: Schoeman M. Corrie , Cotterill F. P. D. (Woody) , Taylor Peter J. , Monadjem Ara 
Published: February 2016

Abstract
We tested the prediction that at coarse spatial scales, variables associated with climate, energy, and productivity hypotheses should be better predictor(s) of bat species richness than those associated with environmental heterogeneity. Distribution ranges of 64 bat species were estimated with niche-based models informed by 3629 verified museum specimens. The influence of environmental correlates on bat richness was assessed using ordinary least squares regression (OLS), simultaneous autoregressive models (SAR), conditional autoregressive models (CAR), spatial eigenvector-based filtering models (SEVM), and Classification and Regression Trees (CART). To test the assumption of stationarity, Geographically Weighted Regression (GWR) was used. Bat species richness was highest in the eastern parts of southern Africa, particularly in central Zimbabwe and along the western border of Mozambique. We found support for the predictions of both the habitat heterogeneity and climate/productivity/energy hypotheses, and as we expected, support varied among bat families and model selection. Richness patterns and predictors of Miniopteridae and Pteropodidae clearly differed from those of other bat families. Altitude range was the only independent variable that was significant in all models and it was most often the best predictor of bat richness. Standard coefficients of SAR and CAR models were similar to those of OLS models, while those of SEVM models differed. Although GWR indicated that the assumption of stationarity was violated, the CART analysis corroborated the findings of the curve-fitting models. Our results identify where additional data on current species ranges, and future conservation action and ecological work are needed.
Phenotypic plasticity of labile traits in the wild
Authors: Brommer Jon E. 
Published: February 2016

Abstract
Individual-based studies allow quantification of phenotypic plasticity in behavioural, life-history and other labile traits. The study of phenotypic plasticity in the wild can shed new light on the ultimate objectives (1) whether plasticity itself can evolve or is constrained by its genetic architecture, and (2) whether plasticity is associated to other traits, including fitness (selection). I describe the main statistical approach for how repeated records of individuals and a description of the environment (E) allow quantification of variation in plasticity across individuals (IxE) and genotypes (GxE) in wild populations. Based on a literature review of life-history and behavioural studies on plasticity in the wild, I discuss the present state of the two objectives listed above. Few studies have quantified GxE of labile traits in wild populations, and it is likely that power to detect statistically significant GxE is lacking. Apart from the issue of whether it is heritable, plasticity tends to correlate with average trait expression (not fully supported by the few genetic estimates available) and may thus be evolutionary constrained in this way. Individual-specific estimates of plasticity tend to be related to other traits of the individual (including fitness), but these analyses may be anti-conservative because they predominantly concern stats-on-stats. Despite the increased interest in plasticity in wild populations, the putative lack of power to detect GxE in such populations hinders achieving general insights. I discuss possible steps to invigorate the field by moving away from simply testing for presence of GxE to analyses that ‘scale up’ to population level processes and by the development of new behavioural theory to identify quantitative genetic parameters which can be estimated.
The measurement of sexual selection on females and males
Authors: Fritzsche Karoline , Booksmythe Isobel 
Published: February 2016

Abstract
As in any field of research, the study of sexual selection is subject to ongoing debate over definitions and interpretations of the fundamental concepts involved. These arguments generally promote progress, as they highlight areas where current explanations are incomplete. Here we briefly review two ongoing discussions in the sexual selection literature. First, the definition of sexual selection has received renewed interest in light of increasing research effort into when and how it operates in females. Second, how best to measure sexual selection is an ongoing subject of debate; in practice, recognition that the appropriate measures depend on the focus of the specific study, and that multiple measures should be employed wherever possible, seems to provide the most informative approach. The wide scope of recent empirical work in these and related areas, with the application of new techniques and approaches, reflects that the field of sexual selection is being constantly expanded and enriched.
Hybridization and genome evolution II: Mechanisms of species divergence and their effects on evolution in hybrids
Authors: Bailey Richard I. , Eroukhmanoff Fabrice , Sætre Glenn-Peter 
Published: February 2016

Abstract
Recent genomic studies have highlighted the importance of hybridization and gene exchange in evolution. We ask what factors cause variation in the impact of hybridization, through adaptation in hybrids and the likelihood of hybrid speciation. During speciation, traits that diverge due to both divergent and stabilizing selection can contribute to the buildup of reproductive isolation. Divergent directional selection in parent taxa should lead to intermediate phenotypes in hybrids, whereas stabilizing selection can also produce extreme, transgressive phenotypes when hybridization occurs. By examining existing theory and empirical data, we discuss how these effects, combined with differences between modes of divergence in the chromosomal distribution of incompatibilities, affect adaptation and speciation in hybrid populations. The result is a clear and testable set of predictions that can be used to examine hybrid adaptation and speciation. Stabilizing selection in parents increases transgression in hybrids, increasing the possibility for novel adaptation. Divergent directional selection causes intermediate hybrid phenotypes and increases their ability to evolve along the direction of parental differentiation. Stabilizing selection biases incompatibilities towards autosomes, leading to reduced sexual correlations in trait values and reduced pleiotropy in hybrids, and hence increased freedom in the direction of evolution. Directional selection causes a bias towards sex-linked incompatibilities, with the opposite consequences. Divergence by directional selection leads to greater dominance effects than stabilizing selection, with major but variable impacts on hybrid evolution.
The influence of terrain age and altitude on the arthropod communities found on recently deglaciated terrain
Authors: Franzén Markus , Dieker Petra 
Published: February 2016

Abstract
Climate warming has been more pronounced in the Arctic than elsewhere, resulting in a recent rapid glacial retreat. Over 85% of the Ålmajallojekna glacier has disappeared over the last 115 years and it is one of the fastest retreating glaciers in Sweden. In 2011 and 2012, at 18 sites in the vicinity of the remaining glacier network, we sampled arthropods and related the species richness, abundance and proportion of herbivores to altitude (ranging from 824 to 1, 524 m.a.s.l.) and the age of the site (ranging from 0 to &gt;115 years). Temperature was measured at six sites and the average annual air temperature ranged from -3.7°C to 1.1°C. In total, we recorded 3, 705 arthropods from 117 species in nine different taxonomic groups. The most abundant and species-rich group was Coleoptera (1, 381 individuals, 41 species) followed by Araneae (1, 050 individuals, 15 species) and Mac-rolepidoptera (732 individuals, 17 species). Only at lower altitudes did the abundance and species richness of arthropods increase with increasing age of the site. The results were consistent among the studied taxonomic groups and when controlling for sampling intensity using two different approaches. The proportion of herbivores decreased with increasing age of the site and with increasing altitude. Clearly, altitude appears more important than the age of the site and, at higher altitudes, abundance, species richness and herbivory are low.
Avian genetic ecotoxicology: DNA of the canary in a coalmine
Authors: Bonisoli-Alquati Andrea 
Published: February 2016

Abstract
Genotoxic chemicals, through damage and alteration of the genetic material of wild organisms, pose significant threats to the persistence of wild animal populations. Their damaging effects can ultimately impair the health of the ecosystem and its provision of services to human society. Bird species are good candidates for the role of sentinels of the effects of genotox-ins, thanks to (i) the diversity of their ecological niches, (ii) their ubiquity across environments, (iii) their conspicuousness, abundance and approachability, together with (iv) their well-known life histories and the availability of historical data series. Avian diversity increases the likelihood that adequate model species be available for monitoring genotoxicants and assessing their impact. This paper reviews the methods utilized by genetic ecotoxicological studies of wild birds, highlighting their benefits and shortcomings. It also summarizes the genetic ecotoxicological studies so far conducted. In spite of a paucity of studies, several classes of genotoxicants have already been investigated across a variety of species and environments, thus supporting the versatility of birds as monitors of genotoxic contamination. Future technical advancements and applications are suggested, with particular reference to the analysis of mutational events, gene expression and methylation patterns. Finally, I argue that the development of avian genetic ecotoxicology will contribute to the understanding of natural variation in the underlying machinery for coping with DNA damage and oxidative stress, both of which are increasingly recognized as proximate factors in the evolution of life history adaptations.
The role of aggression in range expansion and biological invasions
Authors: Hudina Sandra , Hock Karlo , žganec Krešimir 
Published: February 2016

Abstract
Traits that aid in the invasion process should exhibit a gradient across the expansion range in response to changing selection pressures. Aggression has been repeatedly associated with invasion success in many taxa, as it may help invaders to wrestle the resources from other species which enhances their success in a novel environment. However, aggression primarily allows individuals to overcome conspecific rivals, providing advantages in competition over resources. Agonistic prowess could therefore increase fitness at both ends of the expansion gradient. Here we review the role of aggression in range expansion of invasive species, and its potential role as a driver of range expansion. We analyze how these different mechanisms could affect trait variation in expanding and invasive populations. Specifically, we look at how aggression could help dilate the edges of a population through niche competition, as well as lead to exclusion from the center (i.e. areas of high population density) by the conspe-cifics. Both of these processes will result in a characteristic spatial distribution of phenotypes related to aggression that could provide insights into the ecological pressures and dynamics of expanding populations, potentially providing clues to their success as niche competitors and invasive species.