bluuebunny/crossref_metadata_2025_split huggingface dataset:
What is the sound of fear? Behavioral responses of white-crowned sparrows Zonotrichia leucophrys to synthesized nonlinear acoustic phenomena
Authors: Blesdoe Ellen K. , Blumstein Daniel T. 
Published: February 2016

Abstract
Fear and anxiety may be adaptive responses to life-threatening situations, and animals may communicate fear to others vocally. A fundamental understanding of fear inducing sounds is important for both wildlife conservation and management because it helps us understand how to design repellents and also how (and why) animals may be negatively impacted by anthropogenic sounds. Nonlinear phenomena—sounds produced by the desynchronization of vibrations in a sound production system—are commonly found in stress-induced animal vocalizations, such as in alarm calls, mobbing calls, and fear screams. There are several functional hypotheses for these nonlinear phenomena. One specific hypothesis is the unpredictability hypothesis, which suggests that because nonlinear phenomena are more variable and somewhat unpredictable, animals are less likely to habituate to them. Animals should, therefore, have a prolonged response to sounds with nonlinear phenomena than sounds without them. Most of the studies involving nonlinear phenomena have used mammalian subjects and conspecific stimuli. Our study focused on white-crowned sparrows (Zonotrichia leucophrys ssp. oriantha) and used synthesized acoustic stimuli to investigate behavioral responses to stimuli with and without nonlinear phenomena. We predicted that birds would be less relaxed after hearing a stimulus with a nonlinear component. We calculated the difference from baseline of proportion of time spent in relaxed behaviors and performed pair-wise comparisons between a pure tone control stimulus and each of three experimental stimuli, including a frequency jump up, a frequency jump down, and white noise. These comparisons showed that in the 30‒60 s after the playback experiment, birds were significantly less relaxed after hearing noise or an abrupt frequency jump down an octave but not an abrupt frequency jump up an octave or a pure tone. Nonlinear phenomena, therefore, may be generally arousing to animals and may explain why these acoustic properties are commonly found in animal signals associated with fear [Current Zoology 60 (4): 534–541, 2014].
An integrative view of the signaling phenotype: Dynamic links between signals, physiology, behavior and social context
Authors: Vitousek Maren N. , Zonana David M. , Safran Rebecca J. 
Published: February 2016

Abstract
Signal traits are often linked with the physiological state and behavior of their bearer. Direct examination of the causal links among these variables has provided substantial insight into the information content of signals, and into the costs and benefits of signal expression. Yet recent empirical work suggests that the social context in which signals are developed and displayed can play a major role not only in how signals are received, but also in coordinating and mediating the signaling phenotype itself. Here we review both well-established and emerging evidence for direct feedbacks among an individual’s physiological state, behavior, and signal elaboration. We then describe an integrative view of signaling that takes into account the bidirectional relationships among components of phenotype and the social context in which signals are developed and displayed. Integrating dynamic feedback between context and phenotype within models of the evolution and maintenance of signals may yield insights into how signals evolve, how signaling phenotypes are coordinated and maintained on ecological and evolutionary time scales, and how static signals continue to convey relevant phenotypic information about their bearer through time.
Endocrine correlates of mate choice and promiscuity in females of a socially monogamous avian mating system with alternative male reproductive phenotypes
Authors: Schwabl Hubert , Lindsay Willow R. , Barron Douglas G. , Webster Michael S. 
Published: February 2016

Abstract
While our understanding of male reproductive strategies is informed by extensive investigations into endocrine mechanisms, the proximate mechanisms by which females compete for mates and adjust reproduction to social environment remains enigmatic. We set out to uncover endocrine correlates of mate choice, social environment, and reproductive investment in female red-backed fairy-wrens Malurus melanocephalus. In this socially monogamous, yet highly sexually promiscuous species, females experience discrete variation in the phenotype of their mates, which vary in both plumage signals and level of paternal care, and in the composition of their breeding groups, which consist of either the pair alone or with an additional cooperative auxiliary; female investment varies according to these social parameters. We found that androgen, estrogen, and glucorticoid levels varied with reproductive stage, with highest androgen and estrogen concentrations during nest construction and highest corticosterone concentrations during the pre-breeding stage. These stage-dependent patterns did not vary with male phenotype or auxiliary presence, though androgen levels during pre-breeding mate selection were lower in females obtaining red/black mates than those obtaining brown mates. We found no evidence that androgen, estrogen, or corticosterone levels during the fertile period were related to extra-pair young (EPY) frequency. This study demonstrates clear changes in steroid levels with reproductive stage, though it found little support for variation with social environment. We suggest hormonal responsiveness to social factors may be physiologically constrained in ways that are bypassed through exogenous hormone manipulations.
Are genetically distinct lizard species able to hybridize? A review
Authors: Jančúchová-Lásková Jitka , Landová Eva , Frynta Daniel 
Published: February 2016

Abstract
Animal species are delimited by reproductive isolation mechanisms (RIMs). Postzygotic RIMs are mainly products of genetic differences and thus their strength increases with elapsed divergence time. The relationship between postzygotic reproductive isolation and genetic divergence, however, differs considerably among major clades of vertebrates. We reviewed the available literature providing empirical evidence of natural and/or experimental hybridization between distinct species of lizards (squamates except snakes). We found that hybridization events are widely distributed among nearly all major lizard clades. The majority of research focuses on parthenogenetic species and/or polyploid hybrids in families Lacertidae, Teiidae and Gekkonidae. Homoploid bisexual hybrids are mainly reported within Lacertidae and Iguania groups. As a proxy of genetic divergence of the hybridizing taxa we adopted nucleotide sequence distance (HKY85) of mitochondrial cyt b gene. The upper limit of genetic divergence was similar with regard to both parthenogenetic and bisexual hybrids. Maximum values of these distances between hybridizing species of lizards approached 18%?21%, which is comparable to or even exceeds the corresponding values reported for other principal clades of vertebrates. In spite of this, F1 hybrids are typically at least partially fertile in lizards and thus genetic in-trogression between highly divergent species is possible. The relationship between the genetic distance and hybrid fertility was not found.
Cross inhibition improves activity selection when switching incurs time costs
Authors: Marshall James A R , Favreau-Peigné Angélique , Fromhage Lutz , Mcnamara John M , Meah Lianne F S , Houston Alasdair I 
Published: February 2016

Abstract
We consider a behavioural model of an animal choosing between two activities, based on positive feedback, and examine the effect of introducing cross inhibition between the motivations for the two activities. While cross-inhibition has previously been included in models of decision making, the question of what benefit it may provide to an animal’s activity selection behaviour has not previously been studied. In neuroscience and in collective behaviour cross-inhibition, and other equivalent means of coupling evidence-accumulating pathways, have been shown to approximate statistically-optimal decision-making and to adaptively break deadlock, thereby improving decision performance. Switching between activities is an ongoing decision process yet here we also find that cross-inhibition robustly improves its efficiency, by reducing the frequency of costly switches between behaviours.
Convergent evolution of brain morphology and communication modalities in lizards
Authors: Robinson Christopher D. , Patton Michael S. , Andre Brittney M. , Johnson Michele A. 
Published: February 2016

Abstract
Animals communicate information within their environments via visual, chemical, auditory, and/or tactile modalities. The use of each modalityis generally linked to particular brain regions, but it is not yet known whether the cellular morphology of neurons in these regions has evolved in association with the relative use of a modality.We investigated relationships between the behavioral use of communication modalities and neural morphologies in six lizard species. Two of these species (Anolis carolinensis and Leiocephalus carinatus) primarily use visual signals to communicate with conspecifics and detect potential prey, and two (Aspidoscelis gularis and Scincella lateralis) communicate and forage primarily using chemical signals. Two other species (Hemidactylus turcicus and Sceloporus olivaceus) use both visual and chemical signals. For each species, we performed behavioral observations and quantified rates of visual and chemical behaviors. We then cryosectioned brain tissues from 9–10 males of each species and measured the soma size and density of neurons in two brain regions associated with visual behaviors (the lateral geniculate nucleus and the nucleus rotundus) and one region associated with chemical behaviors (the nucleus sphericus). With analyses conducted in a phylogenetic context, we found that species that performed higher rates of visual displays had a denser lateral geniculate nucleus, and species that used a higher proportion of chemical displays had larger somas in the nucleus sphericus. These relationships suggest that neural morphologies in the brain have evolved convergently in species with similar communication behaviors.
Evolution of a flexible rule for foraging that copes with environmental variation
Authors: Higginson Andrew D. , Fawcett Tim W. , Houston Alasdair I. 
Published: February 2016

Abstract
Models of adaptive behaviour typically assume that animals behave as though they have highly complex, detailed strategies for making decisions. In reality, selection favours the optimal balance between the costs and benefits of complexity. Here we investigate this trade-off for an animal that has to decide whether or not to forage for food – and so how much energy reserves to store – depending on the food availability in its environment. We evolve a decision rule that controls the target reserve level for different ranges of food availability, but where increasing complexity is costly in that metabolic rate increases with the sensitivity of the rule. The evolved rule tends to be much less complex than the optimal strategy but performs almost as well, while being less costly to implement. It achieves this by being highly sensitive to changing food availability at low food abundance – where it provides a close fit to the optimal strategy – but insensitive when food is plentiful. When food availability is high, the target reserve level that evolves is much higher than under the optimal strategy, which has implications for our understanding of obesity. Our work highlights the important principle of generalisability of simple decision-making mechanisms, which enables animals to respond reasonably well to conditions not directly experienced by themselves or their ancestors.
Temperature effect on the sensitivity of the copepod Eucyclops serrulatus (Crustacea, Copepoda, Cyclopoida) to agricultural pollutants in the hyporheic zone
Authors: Lorenzo Tiziana DI , Di Marzio Walter D. , Cifoni Marco , Fiasca Barbara , Baratti M. , Sáenz Maria E. , Galassi Diana M.P. 
Published: February 2016

Abstract
The sensitivity of freshwater invertebrates to agricultural pollutants is supposed to increase with rising temperature due to global warming. The aim of this study was to measure the effect of temperature on the lethal toxicity of ammonia-N, the herbicide Imazamox and the mixture of the two chemicals, in the adults and the juveniles of a population of the copepod Eucyclops serrulatus. This is a widely distributed species found in surface waters, in transitional habitats between surface water and groundwater, and in genuine groundwater environments. We tested the sensitivity by short-term bioassays (96 h) at 15°C and 18°C, respectively. Our results highlighted the following: (1) increasing temperature affected the sensitivity of the adults to ammonia-N and of the juveniles to the mixture, all of which were more sensitive to its detrimental effects at 18°C; (2) the juvenile stages were more sensitive than the adults to all toxicants, and (3) for all combinations of chemicals and temperatures, the effects were synergistic and approximately one order of magnitude greater than those expected according to a concentration addition model when comparing the LC50 for each chemical in the mixture with the LC50s of chemicals individually assayed. Overall, in a context of global change, ammonia-N and mixtures of agricultural pollutants may affect the survival rate of species that spend a part or the whole life-cycle in the hyporheic habitat, with detrimental effects to biodiversity and ecosystem services provided by the hyporheic biota.
Impacts of climate change on the ecotoxicology of chemical contaminants in estuarine organisms
Authors: Delorenzo Marie E. 
Published: February 2016

Abstract
Global climate change effects will vary geographically, and effects on estuaries should be independently considered. This review of the impacts of climate change on the ecotoxicology of chemical contaminants aims to summarize responses that are specific to estuarine species. Estuarine organisms are uniquely adapted to large fluctuations in temperature, salinity, oxygen, and pH, and yet future changes in climate may make them more susceptible to chemical contaminants. Recent research has highlighted the interactive effects of chemical and nonchemical stressors on chemical uptake, metabolism, and organism survival. Assessments have revealed that the nature of the interaction between climate variables and chemical pollution will depend on estuarine species and life stage, duration and timing of exposure, prior stressor exposure, and contaminant class. A need for further research to elucidate mechanisms of toxicity under different abiotic conditions and to incorporate climate change factors into toxicity testing was identified. These efforts will improve environmental risk assessment of chemical contaminants and management capabilities under changing climate conditions.
Forecasting the impacts of chemical pollution and climate change interactions on the health of wildlife
Authors: Noyes Pamela D. , Lema Sean C. 
Published: February 2016

Abstract
Global climate change is impacting organisms, biological communities and ecosystems around the world. While most research has focused on characterizing how the climate is changing, including modeling future climatic conditions and predicting the impacts of these conditions on biodiversity, it is also the case that climate change is altering the environmental impacts of chemical pollution. Future climate conditions are expected to influence both the worldwide distribution of chemicals and the toxicological consequences of chemical exposures to organisms. Many of the environmental changes associated with a warming global climate (e.g., increased average – and possibly extreme – temperatures; intense periods of drier and wetter conditions; reduced ocean pH; altered salinity dynamics in estuaries) have the potential to enhance organism susceptibility to chemical toxicity. Additionally, chemical exposures themselves may impair the ability of organisms to cope with the changing environmental conditions of the shifting climate. Such reciprocity in the interactions between climate change and chemicals illustrates the complexity inherent in predicting the toxicological consequences of chemical exposures under future climate scenarios. Here, we summarize what is currently known about the potential reciprocal effects of climate change and chemical toxicity on wildlife, and depict current approaches and ongoing challenges for incorporating climate effects into chemical testing and assessment. Given the rapid pace of new man-made chemistries, the development of accurate and rapid methods to evaluate multiple chemical and non-chemical stressors in an ecologically relevant context will be critical to understanding toxic and endocrine-disrupting effects of chemical pollutants under future climate scenarios.
Color change in a marine isopod is adaptive in reducing predation
Authors: Hultgren Kristin M. , Mittelstaedt Hannah 
Published: February 2016

Abstract
Although background matching is a common form of camouflage across a wide diversity of animals, there has been surprisingly little experimental work testing the fitness consequences of this camouflage strategy, especially in marine ecosystems. In this study, we tested whether color camouflage enhances survival of the intertidal marine isopod Pentidotea (Idotea) wosnesenskii, quantified patterns of camouflage in different algal habitats, and examined how algal diet affected color change and growth using laboratory assays. In the field, isopods collected from two differently colored algal habitats (the brown alga Fucus distichus and the red alga Odonthalia floccosa) matched the color of their respective algal habitats, and also differed significantly in body size: smaller red isopods were found on red algae, while larger brown isopods were found on brown algae. Predation experiments demonstrated these color differences had fitness benefits: brown isopods that matched their brown algae habitats survived at higher rates than red unmatched isopods. Surprisingly, despite the propensity of isopods to match their algal habitats, algal diet had no effect on color change in color change experiments. Instead, isopods in all treatments turned browner, matching the color of the algal habitat that many isopods are found on as adults. In summary, our data supported our hypothesis that background matching serves an adaptive function in reducing predation, with important evolutionary implications for explaining the wide variation in color change mechanisms in idoteid isopods.
Estimating the geographic range of a threatened shark in a data-poor region: Cetorhinus maximus in the South Atlantic Ocean
Authors: Lucifora Luis O. , Barbini Santiago A. , Di Giácomo Edgardo E. , Waessle Juan A. , Figueroa Daniel E. 
Published: February 2016

Abstract
The distribution of the planktivorous basking shark Cetorhinus maximus is influenced by zooplankton abundance at small scales and temperature at medium scales in the North Atlantic. Here, we estimate the distribution of basking sharks on South Atlantic continental shelves, and the relative importance of chlorophyll concentration, as a proxy for zooplankton abundance, and temperature in determining habitat suitability for basking sharks at large scales. We used maximum entropy (MaxEnt) and maximum likelihood (MaxLike) species distribution modelling to test three hypotheses: the distribution of basking sharks is determined by (1) temperature, (2) chlorophyll concentration, or (3) both chlorophyll and temperature, while considering other factors, such as oxygen and salinity. Off South America, basking shark habitat included subtropical, temperate and cool-temperate waters between approximately 20°S and 55°S. Off Africa, basking shark habitat was limited to cool-temperate waters off Namibia and southern South Africa. MaxLike models had a better fit than MaxEnt models. The best model included minimum chlorophyll concentration, dissolved oxygen concentration, and sea surface temperature range, supporting hypothesis 3. However, of all variables included in the best model, minimum chlorophyll concentration had the highest influence on basking shark distribution. Unlike the North Atlantic distribution, the South Atlantic distribution of basking sharks includes subtropical and cool-temperate waters. This difference is explained by high minimum chlorophyll concentration off southern Brazil as compared to North Atlantic subtropical areas. Observations in other regions of the world support this conclusion. The highest habitat suitability for basking sharks is located close to nearshore areas that experience high anthropogenic impact.
An Audience of One: Behaviorally Targeted Ads as Implied Social Labels
Authors: Summers Christopher A. , Smith Robert W. , Reczek Rebecca Walker 
Published: February 2016

Abstract
“Behavioral targeting” is an Internet-based targeting strategy that delivers digital ads to individuals based on their online behavior (e.g., search, shopping). This research explores the unique ways in which consumers respond to ads using this type of targeting (vs. to ads that use more traditional forms of targeting), demonstrating that a behaviorally targeted ad can act as a social label even when it contains no explicit labeling information. Instead, when consumers recognize that the marketer has made an inference about their identity in order to serve them the ad, the ad itself functions as an implied social label. Across four studies, behaviorally targeted ads lead consumers to make adjustments to their self-perceptions to match the implied label; these self-perceptions then impact behavior including purchase intentions for the advertised product and other behaviors related to the implied label. Importantly, these effects only hold when the label is plausibly connected to consumers’ prior behavior (i.e., when the targeting is at least moderately accurate).