Justin Boyles

Southern Illinois University Carbondale | SIU · School of Biological Sciences

Populations wax and wane over time in response to an organism's interactions with abiotic and biotic forces. Numerous studies demonstrate that fluctuations in local populations can lead to shifts in relative population densities across the geographic range of a species over time. Fewer studies attempt to disentangle the causes of such shifts. Over...

Manipulation of microclimates in caves and mines has gained renewed interest as a conservation and management strategy for populations of hibernating bats devastated by white‐nose syndrome (WNS). WNS creates an energy imbalance for hibernating bats and ultimately leads to starvation, so some researchers and management agencies suggest modifying hib...

As researchers, teachers, and practitioners we often encounter young professionals and lay adults who do not understand basics of mammalian body temperature regulation. Often their single solid piece of knowledge is that some vertebrates (mammals and birds) are warm-blooded and some (fish, amphibians, and reptile) are cold-blooded, which is incorre...

White-nose syndrome has killed millions of bats, yet both the origins and infection strategy of the causative fungus, Pseudogymnoascus destructans, remain elusive. We provide evidence for a novel hypothesis that P. destructans emerged from plant-associated fungi and retained invasion strategies affiliated with fungal pathogens of plants. We demonst...

Disease results from interactions among the host, pathogen, and environment. Inoculation trials can quantify interactions among these players and explain aspects of disease ecology to inform management in variable and dynamic natural environments. White-nose Syndrome, a disease caused by the fungal pathogen, Pseudogymnoascus destructans ( Pd ), has...

Hibernators adjust the expression of torpor behaviourally and physiologically to balance the benefits of energy conservation in hibernation against the physiological and ecological costs. Small fat-storing species, like many cave-hibernating bats, have long been thought to be highly constrained in their expression of hibernation because they must s...

There is increasing recognition that rather than being fully homeothermic, most endotherms display some degree of flexibility in body temperature. However, the degree to which this occurs varies widely from the relatively strict homeothermy in species, such as humans to the dramatic seasonal hibernation seen in Holarctic ground squirrels, to many p...

Environmental and biotic pressures impose homeostatic costs on all organisms. The energetic costs of maintaining high body temperatures (Tb) render endotherms sensitive to pressures that increase foraging costs. In response, some mammals become more heterothermic to conserve energy. We measured Tb in banner-tailed kangaroo rats (Dipodomys spectabil...

Energy conservation has long been a focal point in hibernation research. A long-standing assumption is that ambient temperature (Ta) largely defines the rate of energy expenditure because of well-known relationships between Ta, metabolic rate, and frequency of arousal from torpor. Body condition and humidity also affect energy expenditure but are u...

Winter is a time of fascinating changes in biology for cave-hibernating bats, but it is also a time of vulnerability. Unsurprisingly, assessments of winter habitat for these mammals and how it can be managed have been a focus of many researchers involved with the North American Society for Bat Research over the last 50 years. Over this time, a para...

The first radiotelemetry study of bats was published in 1967, nearly coinciding with the first meeting in 1970 of bat biologists that evolved into the North American Society for Bat Research. Thus, NASBR provides a useful lens to assess the maturation of how this technology has been used in bat research. Researchers may view this developmental proc...

The global SARS-CoV-2 pandemic and the role of bats in zoonotic spillover have renewed interest in the flight-as-fever hypothesis, which posits that high body temperatures experienced by bats during flight contribute to their high viral tolerance. We argue that flight-as-fever is unlikely to explain why bats harbor more viruses than other mammals o...

Hibernation has received considerable attention from physiologists and natural historians, but theoretical and ecological treatments of hibernation are rarer. There is ample recent evidence that costs associated with hibernation affect the degree to which hibernation is expressed in nature, but we currently lack a quantitative framework under which...

Macrophysiological analyses are useful to predict current and future range limits and improve our understanding of endotherm macroecology, but such analyses too often rely on oversimplifications of endothermic thermoregulatory and energetic physiology, which lessens their applicability. We detail some of the major issues with macrophysiological ana...

Conservation of rare and declining species requires reliable information about life‐history traits and population growth characteristics. Unfortunately, long‐term studies necessary to obtain such data are often difficult or impossible for species of concern. In such cases, data that can be collected during limited capture events can serve as valuab...

Artificial lights may be altering interactions between bats and moth prey. According to the allotonic frequency hypothesis (AFH), eared moths are generally unavailable as prey for syntonic bats (i.e., bats that use echolocation frequencies between 20 and 50 kHz within the hearing range of eared moths) due to the moths’ ability to detect syntonic ba...

Plasma metabolite concentrations can be used to understand nutritional status and foraging behavior across ecological contexts including prehibernation fattening, migration refueling, and variation in foraging habitat quality. Generally, high plasma concentrations of the ketone β-hydroxybutyrate, a product of fat catabolism, indicate fasting, while...

Researchers commonly measure body, orifice, or skin temperature (collectively referred to as body temperature [Tb] herein) of endothermic animals in biomedical, physiological, evolutionary, and ecological studies. However, comparing Tb among species or placing a single study in context is challenging because there is no single, standard method to d...

The effects of animal homeostatic function on ecological interactions have not been well-integrated into community ecology. Animals mediate environmental change and stressors through homeostatic shifts in physiology and behavior, which likely shape ecological interactions and plant communities. Animal responses to stressors can alter their habitat...

Global light pollution threatens to disturb numerous wildlife species, but impacts of artificial light will likely vary among species within a community. Thus, artificial lights may change the environment in such a way as to create winners and losers as some species benefit while others do not. Insectivorous bats are nocturnal and a good model to t...

Over the last century the temporal and spatial distribution of light on Earth has been drastically altered by human activity. Despite mounting evidence of detrimental effects of light pollution on organisms and their trophic interactions, the extent to which light pollution threatens biodiversity on a global scale remains unclear. We assessed the s...

Dietary studies have long shown that insectivorous bats do not often consume mosquitoes, despite cosmopolitan distribution and occasional ubiquity of mosquitoes (Culicidae). The apparent avoidance of mosquitoes relative to availability may relate to their small size, as bats may have difficulties detecting and capturing mosquitoes or they may not r...

While some bats cover long distances during migration, moving thousands of kilometers, most migratory bats are considered regional migrants, thought to move relatively short distances (< 500 km) between hibernacula and maternity sites. However, behavior can vary considerably among species and our understanding of these movements has largely been li...

Light pollution has been increasing around the globe and threatens to disturb natural rhythms of wildlife species. Artificial light impacts the behaviour of insectivorous bats in numerous ways, including foraging behaviour, which may in turn lead to altered prey selection. In a manipulative field experiment, we collected faecal samples from six spe...

Variation in environmental conditions during larval life stages can shape development during critical windows and have lasting effects on the adult organism. Changes in larval developmental rates in response to environmental conditions, for example, can trade-off with growth to determine body size and condition at metamorphosis, which can affect ad...

Documenting variation in thermoregulatory patterns across phylogenetically and geographically diverse taxa is key to understanding the evolution of endothermy and heterothermy in birds and mammals. We recorded body temperature (Tb) in free-ranging desert hedgehogs (Paraechinus aethiopicus) across three seasons in the deserts of Saudi Arabia. Modal...

Management of caves where bats hibernate generally consists of limiting access by humans. This management strategy was successful in the 20th century, when the main conservation concern for most cavernicolous bats species was disturbance during hibernation. However, the conservation landscape of the 21st century is different. Currently, the most pr...

Hibernation has long been known to be an energy bottleneck for temperate-zone bats. As such, considerable research effort has been expended to understand the physiological ecology of bat hibernation and the microclimates necessary for successful hibernation. Still, few long-term datasets of microclimate in bat hibernacula are available, and most de...

Significance Bats are thought to provide valuable services to agriculture by suppressing crop pests, but their ecological role in agricultural systems remains unclear. We implemented a unique field experiment to assess the ecological and economic effect of bats in corn agriculture and found that bats initiated strong and surprising ecological inter...

Land-use changes are a leading cause of biodiversity loss and ecosystem service degradation worldwide, but these changes do not affect all organisms equally. Understanding factors influencing resistance to environmental change is vital for informed conservation. In particular, dietary generalists may withstand environmental change better than speci...

Pseudogymnoascus destructans (Pd) is the causative fungal agent of white-nose syndrome (WNS), an emerging fungal-borne epizootic. WNS is responsible for a catastrophic decline of hibernating bats in North America, yet we have limited understanding of the physiological interactions between pathogen and host. Pd severely damages wings and tail membra...

For better or worse, “publish or perish” has become a driving ethos in academic research. Search committees, tenure committees, and administrators evaluate researchers on both quantity and quality of papers they publish. However, proliferation of journals has led to numerous possible publication outlets, even in relatively narrow subdisciplines, so...

Artificial night lighting threatens to disrupt strongly conserved light‐dependent processes in animals and may have cascading effects on ecosystems as species interactions become altered. Insectivorous bats and their prey have been involved in a nocturnal, co‐evolutionary arms race for millions of years. Lights may interfere with anti‐bat defensive...

AimThe ability of endotherms to physiologically regulate body temperature (Tb) is presumed to be important in the adaptive radiation of birds and mammals. Recently, attention has shifted towards determining the extent and energetic significance of Tb variation documented in an ever-expanding list of species. Thus, we provide the first global synthe...

Bats are among the most economically important nondomesticated mammals in the world. They are well-known pollinators and seed dispersers, but crop pest suppression is probably the most valuable ecosystem service provided by bats. Scientific literature and popular media often include reports of crop pests in the diet of bats and anecdotal or extrapo...

White-nose syndrome (WNS) is an emergent disease estimated to have killed over five million North American bats. Caused by the psychrophilic fungus Geomyces destructans, WNS specifically affects bats during hibernation. We describe temperature-dependent growth performance and morphology for six independent isolates of G. destructans from North Amer...

Mathematical formulas of the seven functions used for analyses. (DOCX)

Descriptive statistics and parameter values for best-fit functions of each isolate. (DOCX)

Maintaining a high and constant body temperature (T b) is thought to enhance performance in endotherms, but such a thermoregulatory pattern is energetically expensive. Thus, some variation in T b is probably universal among endotherms, and several recent attempts have been made to generalize the factors that should cause this variation. Two factors...

Maintaining a high and constant body temperature (T(b) ) is often viewed as a fundamental benefit of endothermy, but variation in T(b) is likely the norm rather than an exception among endotherms. Thus, attempts to elucidate which factors cause T(b) of endotherms to deviate away from the T(b) that maximizes performance are becoming more common. One...

White-nose syndrome (WNS) has caused recent catastrophic declines among multiple species of bats in eastern North America. The disease's name derives from a visually apparent white growth of the newly discovered fungus Geomyces destructans on the skin (including the muzzle) of hibernating bats. Colonization of skin by this fungus is associated with...

Example body temperature data for male and female Damaraland mole-rats (Fukomys damarensis) recorded during summer and winter in the Kalahari Desert, South Africa. (XLSX)

Body temperature (T(b)) is an important physiological component that affects endotherms from the cellular to whole organism level, but measurements of T(b) in the field have been noticeably skewed towards heterothermic species and seasonal comparisons are largely lacking. Thus, we investigated patterns of T(b) patterns in a homeothermic, free-rangi...

We measured body temperature (T(b)) in free-ranging individuals of two species of elephant shrews, namely western rock elephant shrews (Elephantulus rupestris) and Cape rock elephant shrews (E. edwardii), during winter in a winter-rainfall region of western South Africa. These syntopic species have similar ecologies and morphologies and thus potent...

White-nose syndrome (WNS) has caused alarming declines of North American bat populations in the 5 years since its discovery. Affected bats appear to starve during hibernation, possibly because of disruption of normal cycles of torpor and arousal. The importance of hydration state and evaporative water loss (EWL) for influencing the duration of torp...

Xylem sap pH (pH(X)) is critical in determining the quantity of inorganic carbon dissolved in xylem solution from gaseous [CO2] measurements. Studies of internal carbon transport have generally assumed that pH(X) derived from stems and twigs is similar and that pH(X) remains constant through time; however, no empirical studies have investigated the...

We appreciate the comments by Fisher and Naidoo regarding our recent effort to provide a first estimate of how much the disappearance of bats could cost the agricultural industry in the United States. Their critique focuses on the fact that variation in agricultural and ecological systems across the

Climate change is one of the major issues facing natural populations and thus a focus of recent research has been to predict the responses of organisms to these changes. Models are becoming more complex and now commonly include physiological traits of the organisms of interest. However, endothermic species have received less attention than have ect...

Many studies have shown that endotherms become more heterothermic when the costs of thermoregulation are high and/or when limited energy availability constrains thermoregulatory capacity. However, the roles of many ecological variables, including constraints on foraging opportunities and/or success, remain largely unknown. To test the prediction th...

Populations of hibernating bats in the northeastern USA are being decimated by white-nose syndrome (WNS). Although the ultimate cause of death is unknown, one possibility is the premature depletion of fat reserves. The immune system is suppressed during hibernation. Although an elevated body temperature (T b) may facilitate an immune response, it a...

Insectivorous bat populations, adversely impacted by white-nose syndrome and wind turbines, may be worth billions of dollars to North American agriculture.

Methods. A Word document containing details of Methods.

White-nose syndrome (WNS) is causing unprecedented declines in several species of North American bats. The characteristic lesions of WNS are caused by the fungus Geomyces destructans, which erodes and replaces the living skin of bats while they hibernate. It is unknown how this infection kills the bats. We review here the unique physiological impor...

A major focus in the study of endothermic thermoregulation has been the description of thermoregulatory patterns used by various species and/or populations. Compared with ectotherms, relatively few attempts have been made to study the thermoregulation of endotherms in an adaptive framework. We believe that one of the main factors limiting this area...