Providing outdoor recreational opportunities to people and protecting wildlife are dual goals of many land managers. However, recreation is associated with negative effects on wildlife, ranging from ...increased stress hormones1,2 to shifts in habitat use3,4,5 to lowered reproductive success.6,7 Noise from recreational activities can be far reaching and have similar negative effects on wildlife, yet the impacts of these auditory encounters are less studied and are often unobservable. We designed a field-based experiment to both isolate and quantify the effects of recreation noise on several mammal species and test the effects of different recreation types and group sizes. Animals entering our sampling arrays triggered cameras to record video and broadcast recreation noise from speakers ∼20 m away. Our design allowed us to observe and classify behaviors of wildlife as they were exposed to acoustic stimuli. We found wildlife were 3.1–4.7 times more likely to flee and were vigilant for 2.2–3.0 times longer upon hearing recreation noise compared with controls (natural sounds and no noise). Wildlife abundance at our sampling arrays was 1.5 times lower the week following recreation noise deployments. Noise from larger groups of vocal hikers and mountain bikers caused the highest probability of fleeing (6–8 times more likely to flee). Elk were the most sensitive species to recreation noise, and large carnivores were the least sensitive. Our findings indicate that recreation noise alone caused anti-predator responses in wildlife, and as outdoor recreation continues to increase in popularity and geographic extent,8,9 noise from recreation may result in degraded or indirect wildlife habitat loss.
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•Noise from human recreation may have far-reaching effects on wildlife•We experimentally tested the effect of human recreation noises on wildlife•Recreation noise, without any human presence, caused anti-predator responses•Species’ sensitivity varied, but large vocal groups caused the strongest responses
Noise from recreational activities can be far reaching and have negative effects on wildlife, yet the impacts of these auditory encounters are often unobservable. Zeller et al. design an experiment to isolate the effect of recreation noise and test recreation type, group size, and vocalization presence on terrestrial wildlife.
Olfaction is an essential sensory modality for insects and their olfactory environment is mostly made up of plant-emitted volatiles. The terrestrial vegetation produces an amazing diversity of ...volatile compounds, which are then transported, mixed, and degraded in the atmosphere. Each insect species expresses a set of olfactory receptors that bind part of the volatile compounds present in its habitat. Insect odorscapes are thus defined as species-specific olfactory spaces, dependent on the local habitat, and dynamic in time. Manipulations of pest-insect odorscapes are a promising approach to answer the strong demand for pesticide-free plant-protection strategies. Moreover, understanding their olfactory environment becomes a major concern in the context of global change and environmental stresses to insect populations. A considerable amount of information is available on the identity of volatiles mediating biotic interactions that involve insects. However, in the large body of research devoted to understanding how insects use olfaction to locate resources, an integrative vision of the olfactory environment has rarely been reached. This article aims to better apprehend the nature of the insect odorscape and its importance to insect behavioral ecology by reviewing the literature specific to different disciplines from plant ecophysiology to insect neuroethology. First, we discuss the determinants of odorscape composition, from the production of volatiles by plants (section "Plant Metabolism and Volatile Emissions") to their filtering during detection by the olfactory system of insects (section "Insect Olfaction: How Volatile Plant Compounds Are Encoded and Integrated by the Olfactory System"). We then summarize the physical and chemical processes by which volatile chemicals distribute in space (section "Transportation of Volatile Plant Compounds and Spatial Aspects of the Odorscape") and time (section "Temporal Aspects: The Dynamics of the Odorscape") in the atmosphere. The following sections consider the ecological importance of background odors in odorscapes and how insects adapt to their olfactory environment. Habitat provides an odor background and a sensory context that modulate the responses of insects to pheromones and other olfactory signals (section "Ecological Importance of Odorscapes"). In addition, insects do not respond inflexibly to single elements in their odorscape but integrate several components of their environment (section "Plasticity and Adaptation to Complex and Variable Odorscapes"). We finally discuss existing methods of odorscape manipulation for sustainable pest insect control and potential future developments in the context of agroecology (section "Odorscapes in Plant Protection and Agroecology").
As humans increasingly utilize sensitive coastal areas, diving seabirds like the marbled murrelet
Brachyramphus marmoratus
face a unique combination of exposure to pervasive anthropogenic sound and ...acoustically mediated disturbances in terrestrial and marine environments. Despite its threatened status, the sound sensitivities and sensory ecology of this species are unknown, limiting any predictions of the frequencies or sound levels that may induce acoustic impacts. In this study, we measured electrophysiological aerial hearing thresholds for 10 wild individuals captured, sedated, examined inside a field-deployed anechoic chamber and subsequently released. Auditory responses were detected across a 0.5 to 6 kHz frequency range. The median auditory threshold was lowest at 2 kHz (33 dB), while hearing was generally sensitive between 0.75 and 3.8 kHz.
B. marmoratus
thresholds were elevated compared to other studied alcid species. In-air sensitivities were used to provide an initial prediction of underwater hearing thresholds. To further explore the auditory sensory ecology of this solitary-nesting species, hearing data were also compared to short-term recordings (5 d) of the aerial soundscape of a marbled murrelet nesting habitat. The soundscape contained both abiotic and biotic sounds that contributed to broadband sound levels of 46-55 dB re: 20 µPa rms (0.2-10 kHz). This comparatively quiet habitat enabled relatively frequent detection of anthropogenic sounds within the soundscape. Energy from this acoustic pollution consistently overlapped marbled murrelet sound sensitivities, indicating that the species is susceptible to disturbance from a range of noise types.
Biological coloration presents a canvas for the study of ecological and evolutionary processes. Enduring interest in colour‐based phenotypes has driven, and been driven by, improved techniques for ...quantifying colour patterns in ever‐more relevant ways, yet the need for flexible, open frameworks for data processing and analysis persists.
Here we introduce pavo 2, the latest iteration of the r package pavo. This release represents the extensive refinement and expansion of existing methods, as well as a suite of new tools for the cohesive analysis of the spectral and (now) spatial structure of colour patterns and perception. At its core, the package retains a broad focus on (a) the organization and processing of spectral and spatial data, and tools for the alternating (b) visualization, and (c) analysis of data. Significantly, pavo 2 introduces image‐analysis capabilities, providing a cohesive workflow for the comprehensive analysis of colour patterns.
We demonstrate the utility of pavo with a brief example centred on mimicry in Heliconius butterflies. Drawing on visual modelling, adjacency, and boundary strength analyses, we show that the combined spectral (colour and luminance) and spatial (pattern element distribution and boundary salience) features of putative models and mimics are closely aligned.
pavo 2 offers a flexible and reproducible environment for the analysis of colour, with renewed potential to assist researchers in answering fundamental questions in sensory ecology and evolution.
Summary
Recent technical and methodological advances have led to a dramatic increase in the use of spectrometry to quantify reflectance properties of biological materials, as well as models to ...determine how these colours are perceived by animals, providing important insights into ecological and evolutionary aspects of animal visual communication.
Despite this growing interest, a unified cross‐platform framework for analysing and visualizing spectral data has not been available. We introduce pavo, an R package that facilitates the organization, visualization and analysis of spectral data in a cohesive framework. pavo is highly flexible, allowing users to (a) organize and manipulate data from a variety of sources, (b) visualize data using R's state‐of‐the‐art graphics capabilities and (c) analyse data using spectral curve shape properties and visual system modelling for a broad range of taxa.
In this paper, we present a summary of the functions implemented in pavo and how they integrate in a workflow to explore and analyse spectral data. We also present an exact solution for the calculation of colour volume overlap in colourspace, thus expanding previously published methodologies.
As an example of pavo's capabilities, we compare the colour patterns of three African glossy starling species, two of which have diverged very recently. We demonstrate how both colour vision models and direct spectral measurement analysis can be used to describe colour attributes and differences between these species. Different approaches to visual models and several plotting capabilities exemplify the package's versatility and streamlined workflow.
pavo provides a cohesive environment for handling spectral data and addressing complex sensory ecology questions, while integrating with R's modular core for a broader and comprehensive analytical framework, automated management of spectral data and reproducible workflows for colour analysis.
Animals moving through the world are surrounded by potential information. But the components of this rich array that they extract will depend on current behavioral requirements and the animal's own ...sensory apparatus. Here, we consider the types of information available to social hymenopteran insects, with a specific focus on ants. This topic has a long history and much is known about how ants and other insects use idiothetic information, sky compasses, visual cues, and odor trails. Recent research has highlighted how insects use other sensory information for navigation, such as the olfactory cues provided by the environment. These cues are harder to understand because they submit less easily to anthropomorphic analysis. Here, we take an ecological approach, considering first what information is available to insects, then how different cues might interact, and finally we discuss potential neural correlates of these behaviors.
When one thinks of airborne organisms, spiders do not usually come to mind. However, these wingless arthropods have been found 4 km up in the sky 1, dispersing hundreds of kilometers 2. To disperse, ...spiders “balloon,” whereby they climb to the top of a prominence, let out silk, and float away. The prevailing view is that drag forces from light wind allow spiders to become airborne 3, yet ballooning mechanisms are not fully explained by current aerodynamic models 4, 5. The global atmospheric electric circuit and the resulting atmospheric potential gradient (APG) 6 provide an additional force that has been proposed to explain ballooning 7. Here, we test the hypothesis that electric fields (e-fields) commensurate with the APG can be detected by spiders and are sufficient to stimulate ballooning. We find that the presence of a vertical e-field elicits ballooning behavior and takeoff in spiders. We also investigate the mechanical response of putative sensory receivers in response to both e-field and air-flow stimuli, showing that spider mechanosensory hairs are mechanically activated by weak e-fields. Altogether, the evidence gathered reveals an electric driving force that is sufficient for ballooning. These results also suggest that the APG, as additional meteorological information, can reveal the auspicious time to engage in ballooning. We propose that atmospheric electricity adds key information to our understanding and predictive capability of the ecologically important mass migration patterns of arthropod fauna 8.
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•Spiders detect electric fields at levels found under natural atmospheric conditions•Ballooning behavior is triggered by such electric fields•Trichobothria mechanically respond to such electric fields, as well as to air flow•Electric field and air flow stimuli elicit distinct displacements of trichobothria
Morley and Robert show that spiders can detect electric fields and respond to this stimulus by attempting to balloon. They conclude that atmospheric electrostatics could provide forces sufficient for dispersal by ballooning in spiders and that hair-shaped sensors are putative electroreceptors.
Because most plants rely on animals for pollination, insights from animal sensory ecology and behavior are essential for understanding the evolution of flowers. In this review, we compare and ...contrast three main types of pollinator responses to floral signals – receiver bias, ‘adaptive’ innate preferences, and associative learning – and discuss how they can shape selection on floral signals. We show that pollinator-mediated selection on floral signals can be strong and that the molecular bases of floral signal variation are often surprisingly simple. These new empirical and conceptual insights into pollinator-mediated evolution provide a framework for understanding patterns of both convergent (pollination syndromes) and advergent (floral mimicry) floral signal evolution.
Because habitats present different costs and benefits in contexts ranging from foraging to mating to predator avoidance, decisions about habitat use likely involve significant trade-offs across ...behavioural contexts. We examine this possibility in Schizocosa floridana, a cursorial wolf spider whose habitat consists of multiple substrates, including oak and pine litter, and sand. However, S. floridana restricts its use of habitat to oak litter. Substrate environments vary significantly in the degree to which they transmit visual and vibratory information. Previous work found that oak litter best transmits the substrate-borne vibrations that are critical to mating communication. However, oak litter may reduce the availability of visual information, which is known to be important for prey capture in other wolf spider species. Here, we test the relationship between substrate and prey capture efficiency in S. floridana. We examine substrate use in a foraging context via two laboratory-based experiments to (1) assess differences in prey capture efficiency among the three most common substrates in the field and to (2) determine which sensory modalities are involved in prey capture. We found that prey capture rates were highest on sand despite the fact that sand is the least used substrate by S. floridana in the wild. We also found no conclusive evidence that either the visual or the vibratory sensory modalities are critical for prey capture. Our results thus suggest that strict habitat specialization such as that exhibited by S. floridana is beneficial in some ecological contexts but costly in others.
•Schizocosa floridana wolf spiders restrict their habitat use to oak litter.•Spiders catch prey more efficiently on sand than on oak litter.•Sand transmits substrate-borne vibrations poorly.•Loss of vibratory or visual sensory information does not impede prey capture.
Predators and prey exist in persistent conflict that often hinges on deception-the transmission of misleading or manipulative signals-as a means for survival. Deceptive traits are widespread across ...taxa and sensory systems, representing an evolutionarily successful and common strategy. Moreover, the highly conserved nature of the major sensory systems often extends these traits past single species predator-prey interactions toward a broader set of perceivers. As such, deceptive traits can provide a unique window into the capabilities, constraints and commonalities across divergent and phylogenetically-related perceivers. Researchers have studied deceptive traits for centuries, but a unified framework for categorizing different types of post-detection deception in predator-prey conflict still holds potential to inform future research. We suggest that deceptive traits can be distinguished by their effect on object formation processes. Perceptual objects are composed of physical attributes (what) and spatial (where) information. Deceptive traits that operate after object formation can therefore influence the perception and processing of either or both of these axes. We build upon previous work using a perceiver perspective approach to delineate deceptive traits by whether they closely match the sensory information of another object or create a discrepancy between perception and reality by exploiting the sensory shortcuts and perceptual biases of their perceiver. We then further divide this second category, sensory illusions, into traits that distort object characteristics along either the what or where axes, and those that create the perception of whole novel objects, integrating the what/where axes. Using predator-prey examples, we detail each step in this framework and propose future avenues for research. We suggest that this framework will help organize the many forms of deceptive traits and help generate predictions about selective forces that have driven animal form and behavior across evolutionary time.
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