Effects of Low-Level Artificial Light at Night on Kentucky Bluegrass and Introduced Herbivore

Increasing evidence suggests that artificial light at night (ALAN) can negatively impact organisms. However, most studies examine the impacts of ALAN on a single species or under high levels of artificial light that are infrequent or unrealistic in urban environments. We currently have little information on how low levels of artificial light emanating from urban skyglow affect plants and their interactions with herbivores. We examined how low levels of ALAN affect grass and insects, including growth rate, photosynthesis, and stomatal conductance in grass, and foraging behavior and survival in crickets. We compared growth and leaf-level gas exchange of Kentucky Bluegrass (Poa pratensis) under low-levels of ALAN (0.3 lux) and starlight conditions (night light at 0.001 lux). Furthermore, each light treatment was divided into treatments with and without house crickets (Acheta domesticus). Without crickets present, bluegrass grown under artificial light at night for three weeks grew taller than plants grown under natural night light levels. Once crickets were introduced at the end of week three, grass height decreased resulting in no measurable effects of light treatment. There were no measurable differences in grass physiology among treatments. Our results indicate that low levels of light resulting from skyglow affect plant growth initially. However, with herbivory, ALAN effects on grass may be inconsequential. Gaining an understanding of how ALAN affects plant-insect interactions is critical to predicting ecological and evolutionary consequences of anthropogenic disturbance

Why conservation biology can benefit from sensory ecology

Global expansion of human activities is associated with the introduction of novel stimuli, such as anthropogenic noise, artificial lights and chemical agents. Progress in documenting the ecological effects of sensory pollutants is weakened by sparse knowledge of the mechanisms underlying these effects. This severely limits our capacity to devise mitigation measures. Here, we integrate knowledge of animal sensory ecology, physiology and life history to articulate three perceptual mechanisms—masking, distracting and misleading—that clearly explain how and why anthropogenic sensory pollutants impact organisms. We then link these three mechanisms to ecological consequences and discuss their implications for conservation. We argue that this framework can reveal the presence of ‘sensory danger zones’, hotspots of conservation concern where sensory pollutants overlap in space and time with an organism’s activity, and foster development of strategic interventions to mitigate the impact of sensory pollutants. Future research that applies this framework will provide critical insight to preserve the natural sensory world

Enlightening Butterfly Conservation Efforts: The Importance of Natural Lighting for Butterfly Behavioral Ecology and Conservation

Light is arguably the most important abiotic factor for living organisms. Organisms evolved under specific lighting conditions and their behavior, physiology, and ecology are inexorably linked to light. Understanding light effects on biology could not be more important as present anthropogenic effects are greatly changing the light environments in which animals exist. The two biggest anthropogenic contributors changing light environments are: (1) anthropogenic lighting at night (i.e., light pollution); and (2) deforestation and the built environment. I highlight light importance for butterfly behavior, physiology, and ecology and stress the importance of including light as a conservation factor for conserving butterfly biodiversity. This review focuses on four parts: (1) Introducing the nature and extent of light. (2) Visual and non-visual light reception in butterflies. (3) Implications of unnatural lighting for butterflies across several different behavioral and ecological contexts. (4). Future directions for quantifying the threat of unnatural lighting on butterflies and simple approaches to mitigate unnatural light impacts on butterflies. I urge future research to include light as a factor and end with the hopeful thought that controlling many unnatural light conditions is simply done by flipping a switch

Anartia Clay Model Attack Data

These are the attack data for all of the models placed in the field. Each model belongs to a group of three different models. This text file lists each model and if it was not attacked (NA), missing (which were censored), and if they were attacked by an avian predator (Avian)

Data from: Keeping the band together: evidence for false boundary disruptive coloration in a butterfly

There is a recent surge of evidence supporting disruptive coloration, in which patterns break up the animal's outline through false edges or boundaries, increasing survival in animals by reducing predator detection and/or preventing recognition. Though research has demonstrated that false edges are successful for reducing predation of prey, research into the role of internal false boundaries (i.e., stripes and bands) in reducing predation remains warranted. Many animals, have stripes and bands that may function disruptively. Here we test the possible disruptive function of wing band patterning in a butterfly, Anartia fatima, using artificial paper and plasticine models in Panama. We manipulated the band so that one model type had the band shifted to the wing margin (non-disruptive treatment) and another model had a discontinuous band located on the wing margin (discontinuous edge treatment). We kept the natural wing pattern to represent the false boundary treatment. Across all treatment groups, we standardized the area of color and used avian visual models to confirm a match between manipulated and natural wing colors. False boundary models had higher survival than either the discontinuous edge model or the non-disruptive model. There was no survival difference between the discontinuous edge model and the non-disruptive model. Our results demonstrate the importance of wing bands in reducing predation on butterflies and show that markings set in from the wing margin can reduce predation more effectively than marginal bands and discontinuous marginal patterns. This study demonstrates an adaptive benefit of having stripes and bands

Anartia model spectra graph

Here are the average reflectance spectra for the color patches of the models. Each average was from several models and natural butterflies

Peripheral eye dimensions in Longwing (Heliconius) butterflies vary with body size and sex but not light environment nor mimicry ring

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Mate detection in a territorial butterfly—the effect of background and luminance contrast

Many animals search for potential mates or prey using a perch-and-sally strategy. The success of such a strategy will depend on factors that affect the observer's ability to detect a passing resource item. Intrinsic factors (e.g., eye structure and physiology) have received much recent attention, but less is known about effects on object detection in nature and extrinsic factors such as size, coloration, and speed of a passing object and the background against which the object is viewed. Here, we examine how background affects the detection of butterfly models by perched males of the butterfly Asterocampa leilia in the field. We test the hypothesis that male choice of perch site in nature will influence the contrast between the object and background against which it is viewed and that this will influence success in detecting the object. We also test the effect of contrast by manipulating the brightness of the object and presenting butterfly models of different reflectance (ranging from black to white). We found an effect of model luminance, with dark models being most likely to elicit a response regardless of background. Further, there was an effect of background type with models viewed against blue sky eliciting the highest response. Perceived luminance contrast correlates to behavior; highly contrasting objects are more frequently detected. This study expands our understanding of visual system performance and has implications for our understanding of the behavior and evolutionary ecology of perching species

Mate detection in a territorial butterfly-the effect of background and luminance contrast

Many animals search for potential mates or prey using a perch-and-sally strategy. The success of such a strategy will depend on factors that affect the observer's ability to detect a passing resource item. Intrinsic factors (e.g., eye structure and physiology) have received much recent attention, but less is known about effects on object detection in nature and extrinsic factors such as size, coloration, and speed of a passing object and the background against which the object is viewed. Here, we examine how background affects the detection of butterfly models by perched males of the butterfly Asterocampa leilia in the field. We test the hypothesis that male choice of perch site in nature will influence the contrast between the object and background against which it is viewed and that this will influence success in detecting the object. We also test the effect of contrast by manipulating the brightness of the object and presenting butterfly models of different reflectance (ranging from black to white). We found an effect of model luminance, with dark models being most likely to elicit a response regardless of background. Further, there was an effect of background type with models viewed against blue sky eliciting the highest response. Perceived luminance contrast correlates to behavior; highly contrasting objects are more frequently detected. This study expands our understanding of visual system performance and has implications for our understanding of the behavior and evolutionary ecology of perching species

Flight morphology, compound eye structure and dispersal in the bog and the cranberry fritillary butterflies: an inter- and intraspecific comparison

Understanding dispersal is of prime importance in conservation and population biology. Individual traits related to motion and navigation during dispersal may differ: (1) among species differing in habitat distribution, which in turn, may lead to interspecific differences in the potential for and costs of dispersal, (2) among populations of a species that experiences different levels of habitat fragmentation; (3) among individuals differing in their dispersal strategy and (4) between the sexes due to sexual differences in behaviour and dispersal tendencies. In butterflies, the visual system plays a central role in dispersal, but exactly how the visual system is related to dispersal has received far less attention than flight morphology. We studied two butterfly species to explore the relationships between flight and eye morphology, and dispersal. We predicted interspecific, intraspecific and intersexual differences for both flight and eye morphology relative to i) species-specific habitat distribution, ii) variation in dispersal strategy within each species and iii) behavioural differences between sexes. However, we did not investigate for potential population differences. We found: (1) sexual differences that presumably reflect different demands on both male and female visual and flight systems, (2) a higher wing loading (i.e. a proxy for flight performance), larger eyes and larger facet sizes in the frontal and lateral region of the eye (i.e. better navigation capacities) in the species inhabiting naturally fragmented habitat compared to the species inhabiting rather continuous habitat, and (3) larger facets in the frontal region in dispersers compared to residents within a species. Hence, dispersers may have similar locomotory capacity but potentially better navigation capacity. Dispersal ecology and evolution have attracted much attention, but there are still significant gaps in our understanding of the mechanisms of dispersal. Unfortunately, for many species we lack detailed information on the role of behavioural, morphological and physiological traits for dispersal. Our novel study supports the existence of inter- and intra-specific evolutionary responses in both motion and navigation capacities (i.e. flight and eye morphology) linked to dispersal