The effect of artificial light on male breeding-season behaviour in green frogs, Rana clamitans melanota
Canadian Journal of Zoology
Abstract
Artificial night lighting (or ecological light pollution) is only now gaining attention as a source of long-term effects on the ecology of both diurnal and nocturnal animals. The limited data available clearly indicate that artificial light can affect physiology and behaviour of animals, leading to ecological consequences at the population, community, and ecosystem levels. Aquatic ecosystems may be particularly vulnerable to such effects, and nocturnally breeding animals such as frogs may be especially affected. To address this potential, we quantify the effects of artificial light on calling and movement behaviour in a rural population of male green frogs (Rana clamitans melanota (Rafinesque, 1820)) during the breeding season. When exposed to artificial light, frogs produced fewer advertisement calls and moved more frequently than under ambient light conditions. Results clearly demonstrate that male green frog behaviour is affected by the presence of artificial light in a manner that has the potential to reduce recruitment rates and thus affect population dynamics.
... A more immediate effect of ALAN could be linked to foraging behavior, which may have both positive and negative outcomes (Baker & Richardson, 2006;Frank, 2006), depending on the species and context (Iasiello & Colombelli-N egrel, 2024). For example, interactions with fisheries or cargo vessels can vary significantly across different species (Dupuis et al., 2021;Montevecchi, 2023). ...
Artificial light at night (ALAN) has global impacts on animals, often negative, yet its effects in polar regions remains largely underexplored. These regions experience prolonged darkness during the polar night, while human activity and artificial lighting are rapidly increasing. In this study, we analyzed a decade of citizen science data on light‐sensitive seabird occurrences in Longyearbyen, a High‐Arctic port settlement, to examine the impact of environmental factors including ALAN during polar night. Our investigation incorporated remote sensing data on nighttime lights levels, sea ice presence, and air temperature measurements from local meteorological station. Our findings reveal that artificial light may potentially impact seabird diversity in this region, with overall diversity decreasing alongside light intensity. However, the relationship between artificial light and seabird diversity was not uniformly negative; individual species exhibited varied responses. We also detected a correlation between artificial light and air temperature, emphasizing the complexity of environmental interactions. Notably, the piscivorous Black Guillemot (Cepphus grylle), the dominant species in Longyearbyen during the polar night, showed increased contribution in the local seabird assemblage with higher light levels. In contrast, the zooplanktivorous Little Auk (Alle alle) exhibited reduced contribution with higher light intensity and increased presence with higher air temperatures. We hypothesize that these differing responses are closely tied to the distinct dietary habits, varying sensitivity to artificial light due to individual adaptations, and overall ecological flexibility of these species, underscoring the need for further research. This study, which uniquely combines citizen science with remote sensing data, represents the first effort to systematically assess the effects of artificial lighting on seabirds during the polar night. The findings underscore the potential importance of this issue for seabird conservation in polar regions.
... Artificial nighttime lighting disrupts the natural light-dark cycle and interrupts diurnal patterns, particularly in urban ecological networks. This disruption affects the normal reproduction [33], growth, and physiology of animals [34], as well as their nocturnal travel patterns [35,36], leading to changes in population size. The selection of resistance factors in this study included land use type, night lighting, building height, distance from roads, elevation, corrected surface undulation, and water network density. ...
The acceleration of urbanization has resulted in varying degrees of impact on the stability and health of high-density urban ecosystems. Building urban ecological networks is crucial for safeguarding biodiversity and sustaining ecosystem vitality. In this study, the city of Foshan was selected as the study area, which is a prime representative of a high-density water network city. Additionally, a morphological spatial pattern analysis was employed to identify the ecological source. We built an ecological resistance surface using geographic, natural, and behavioral elements, adjusting it based on the density of the water network and the building height. Following this, the circuit theoretical model was utilized to create an ecological network by identifying ecological corridors. There were three key findings. First, the ecological network consisted of 30 ecological source sites and 53 ecological corridors, and 103 ecological “pinch points” and 193 ecological barrier points were identified. Second, the ecological sources were predominantly situated in the southwestern and northern parts of Foshan City. Meanwhile, the suburbs of Foshan City contained the primary ecological barrier points, mainly stemming from new construction sites, while the key ecological “pinch points” were concentrated at river junctions. The third outcome was the recommendations to (a) boost the connectivity of the ecological network in the suburbs, (b) improve the connection of the water network in urban areas, and (c) focus on enhancing landscape connectivity. The objective was to develop approaches for optimizing urban ecological networks, leading to better connectivity and improved ecological network quality.
... A change of 40 min in their arrival time may not have a significant impact on their time budget or reproductive success, but an increase in vigilance could delay their return to their nest and reduce the time they have to perform other behaviours. This both aligns and contrasts with studies in other birds and mammals showing an increase in vigilance (Yorzinski et al. 2015, Zhang et al. 2020 and change in activity patterns (Bird et al. 2004, Baker & Richardson 2006, Russ et al. 2015 under artificially illuminated conditions. Repeated exposure to artificial lights may reduce the time some individuals spend performing other important behaviours, such as self-care behaviours, parental care or resting, which combined with other pressures from their environment could reduce their fitness over time (Chace & Walsh 2006, Samia et al. 2015, Vincze et al. 2016. ...
Coastal developments are ever‐expanding and increasing the use of artificial lights within marine environments. Yet there is conflicting research on the impact of artificial lights on seabirds. Here, we experimentally investigated the impacts of artificial white lights on the behaviours (arrival time, group size, number of groups and vigilance) of breeding Little Penguins Eudyptula minor . Little Penguins are central‐place foragers that spend daylight hours foraging at sea and return to their breeding colony after sunset to attend to their chicks or relieve their incubating partners. We exposed Little Penguins returning to their colony at night to either (1) a self‐sustaining white LED floodlight or (2) a control system with a decoy light turned ‘off’. We used two different landing sites (site 1, site 2) that differed in landscape characteristics to assess whether behavioural responses to light were site‐specific. Little Penguins arrived in larger groups at the landing site 2. Regardless of site, we observed fewer groups that arrived earlier when the light was ‘on’. The effects of artificial light (or ‘lack of artificial light’) on the vigilance of Little Penguins were site‐specific, with Little Penguins spending proportionally more time in vigilance when the light was ‘off’ at site 2 compared with site 1. Our results support the idea that artificial lights produced from coastal developments can alter penguin behaviours, but that the effects of artificial lights can be context‐dependent and need to be assessed on a case‐by‐case basis.
... In certain species of frogs, artificial light at night can affect mating behavior, including the calling behavior and movement of male frogs (Baker and Richardson 2006), mate selection by female frogs (Rand et al. 1997), and nest locations (Tárano 1998). Some of this behavior is believed to result from avoidance of predation in illuminated areas. ...
Outdoor lighting at night is considered essential to modern human life. It allows us to safely extend our daytime activities into the night hours. Without proper precautions, the addition of artificial light at night can change the natural night sky conditions and affect scenic, historic, cultural, scientific, recreational,
and ecological values that depend on darkness and dark night skies. The mission of the Bureau of Land Management (BLM) is to sustain the health, diversity, and productivity of the public lands for the use and enjoyment of present and future generations. BLM-managed lands provide differing types of activities, developments, and visitor services that include outdoor lighting where appropriate to provide for worker and visitor safety, security, and enjoyment. Due to growing public concern and research available about light pollution, this technical note provides a set of best practices for outdoor lighting. The information comes from research and practical experience published by industry and other sources and provides knowledge on the relationships between dark night skies and scenic, historic, cultural, scientific, recreational, and ecological values. This technical note provides an easy reference for a variety of ways the BLM can protect night skies and dark environments by reducing or avoiding sources of light pollution from BLM-managed lands to maintain visible clarity of night skies and ensure a healthful dark environment for wildlife and people.
... Given the importance of light as a source of both energy and information for wildlife (Gaston et al., 2012), ALAN can have diverse consequences for wildlife. For example, ALAN may alter hormone levels (Alaasam et al., 2018;Russart and Nelson, 2018), accelerate development (Dananay and Benard, 2018), alter behavior (Baker and Richardson, 2006;Touzot et al., 2020), and change activity patterns (May et al., 2019;Miner et al., 2021;Ouyang et al., 2017). The variety and extent of these impacts on wildlife makes ALAN a pollutant of growing concern, especially considering the presence of nighttime lighting has expanded rapidly in recent years (Kyba et al., 2023). ...
Artificial light at night (ALAN) is a global pollutant of rising concern. While alterations to natural day-night cycles caused by ALAN can affect a variety of traits, the broader fitness and ecological implications of these ALAN-induced shifts remain unclear. This study evaluated the interactive effects of ALAN and background color on traits that have important implications for predator-prey interactions and fitness: crypsis, background adaptation efficacy, and growth. Using three amphibian species as our models, we discovered that: (1) Exposure to ALAN reduced the ability for some species to match their backgrounds (background adaptation efficacy), (2) Crypsis and background adaptation efficacy were enhanced when tadpoles were exposed to dark backgrounds only, emphasizing the importance of environmental context when evaluating the effects of ALAN, (3) ALAN and background color have a combined effect on a common metric of fitness (growth), and (4) Effects of ALAN were not generalizable across amphibian species, supporting calls for more studies that utilize a diversity of species. Notably, to our knowledge, we found the first evidence that ALAN can diminish background adaptation efficacy in an amphibian species (American toad tadpoles). Collectively, our study joins others in highlighting the complex effects of ALAN on wildlife and underscores the challenges of generalizing ALAN's effect across species, emphasizing the need for a greater diversity of species and approaches used in ALAN research.
Unprecedented rates of urbanisation cause detrimental impacts on the natural environment. Two of the most prominent and ubiquitous urban stressors are artificial light at night (ALAN) and the urban heat island (UHI) effect. Individually, these two stressors have a wide array of effects on physiological, behavioural, and life-history traits of organisms. However, stressors rarely work in isolation, and the potential interactions of ALAN and elevated temperatures on organismal life-history traits, particularly with respect to sexual signalling and reproduction, are not well understood. Here, in a fully factorial design, we manipulated intensities of ALAN exposure (simulating urban light pollution) and/or developmental rearing temperatures (simulating UHI effects) to explore the consequences for juvenile development, survival, sexual signalling, and mating behaviour of the Pacific field cricket, Teleogryllus oceanicus. Our data revealed significant effects of temperature on key life-history traits. Crickets reared under elevated temperatures had higher mortality; reduced adult longevity, altered sexual signalling and male attractiveness. In isolation, ALAN had very limited impacts, reducing male juvenile development time. Similarly, both stressors acting in concert also had little impact; ALAN reduced female developmental duration when reared at control temperatures, but not elevated temperatures. These data suggest very limited effects of combined stressors in this species, while elevated temperatures, consistent with urban heat island effects, had equivocal effects on life-history traits, reducing survival, but potentially increasing male fitness. Our data highlight the complexity of urban stressors on wildlife behaviour and fitness. Understanding these processes is essential as both ALAN and temperature are predicted to intensify.
Light is an environmental factor that is extrinsic to animals themselves and that exerts a profound influence on the regulation of circadian, neurohormonal, metabolic, and neurobehavioral systems of all animals, including research animals. These widespread biologic effects of light are mediated by distinct photoreceptors—rods and cones that comprise the conventional visual system and melanopsin-containing intrinsically photosensitive retinal ganglion cells (ipRGCs) of the nonvisual system that interact with the rods and cones. The rods and cones of the visual system, along with the ipRGCs of the nonvisual system, are species distinct in terms of opsins and opsin concentrations and interact with one another to provide vision and regulate circadian rhythms of neurohormonal and neurobehavioral responses to light. Here, we review a brief history of lighting technologies, the nature of light and circadian rhythms, our present understanding of mammalian photoreception, and current industry practices and standards. We also consider the implications of light for vivarium measurement, production, and technological application and provide simple recommendations on artificial lighting for use by regulatory authorities, lighting manufacturers, designers, engineers, researchers, and research animal care staff that ensure best practices for optimizing animal health and well-being and, ultimately, improving scientific outcomes.
Objective
Artificial light at night (ALAN) is one of the most pervasive and rapidly expanding sources of anthropogenic pollution. Aquatic ecosystems may be especially vulnerable to the effects of ALAN due to their disproportionate exposure to anthropogenic pressures. However, research on mechanisms of response to ALAN by aquatic species remains sparse. Our research investigated the extent to which ALAN influences the nocturnal feeding efficiency of Bluegill Lepomis macrochirus .
Methods
Using an array of outdoor mesocosm tanks, we assigned juvenile Bluegill to five nighttime lighting treatments (control dark, 1 lx, 4 lx, 12 lx, and intermittent 12 lx). We conducted weekly nighttime feeding trials for 6 weeks to assess four prey capture variables, including capture efficiency (the effectiveness of prey strikes), capture rate (the number of prey items captured), strike rate (the frequency of prey strikes), and latency (time elapsed before the first prey strike).
Result
The steady lighting treatments, which were selected based on nighttime urban light intensities we previously measured in the field, had no apparent effect on any of the prey capture variables. However, flashing high‐intensity lights (intended to mimic the effect of passing car headlights on a busy highway) had a significant negative effect on capture rate and strike rate, thereby inhibiting the ability of fish to strike at and capture prey.
Conclusion
Our results demonstrate the potential for light pollution (especially flashing or intermittent lights) to interfere with the foraging behavior of this ecologically and economically important sportfish.
The natural environment can be negatively impacted by a variety of human activities, including the production of artificial light at night. Recent studies suggest that pollution from anthropogenic light alters animal behavior. Despite being highly nocturnal, little attention has been given to anurans and the effects artificial light at night has on their behavior. This study investigated whether artificial light influenced male call site selection in east Texas anurans. Ambient light levels were quantified at five sites that varied in urbanization and artificial light levels. Calling males were located and ambient light was then measured at the male's call location. Light levels at those call locations were compared to the general light environment as measured at random locations in the area. There was a consistent pattern where males at the brightest sites called from locations darker than the general light environment. However, male call locations at the brightest sites were generally brighter than those at the darker sites suggesting that, while male anurans avoid illuminated areas for calling, males in more urbanized populations may be unable to do so. As such, male anurans at sites with higher light pollution may experience a form of habitat loss where preferred darker habitat is not available.
Astronomers consider light pollution to be a growing problem, however few studies have addressed potential effects of light pollution on wildlife. Sunlight is believed to initiate song in many bird species. If light initiates song, then light pollution may be influencing avian song behavior at a population level. This hypothesis predicts that birds breeding in areas with large amounts of artificial light will begin singing earlier in the day than birds in areas with little artificial light. Birds in highly illuminated areas might begin singing earlier than did birds in those same areas in previous years when artificial light levels were known to be, or were presumably, lower. Also, birds should begin singing earlier within a site on brightly lit nights. In 2002 and 2003 I documented initiation of morning song by breeding American Robins (Turdus migratorius) in areas with differing intensity of artificial nocturnal light. I compared my observations among sites and against historical studies. Robin populations in areas with large amounts of artificial light frequently began their morning chorus during true night. Chorus initiation time, relative to civil twilight, was positively correlated with amount of artificial light present during true night. Robin choruses in areas with little, or presumably little, artificial light have almost never begun during true night, instead appearing to track the onset of civil twilight. Proliferation of artificial nocturnal light may be strongly affecting singing behavior of American Robins at a population level.
Field studies were conducted on factor affecting embryo mortality in bullfrogs, Rana catesbeiana, in 1975 and 1976 at the E. S. George Reserve of the University of Michigan. Larger @V produced significantly larger clutches than smaller @V (6000 to >20,000). Older @V produced 2 clutches each year with 2nd clutches containing significantly fewer eggs than 1st clutches. Egg size appeared to be unrelated to @V size; however, 2nd clutches contained significantly smaller eggs than initial clutches for all @V @V. Embryo mortality depended on @V choice of oviposition sites. Such sites were controlled by territorial @M @M. Larger @M @M controlled oviposition sites that had significantly lower embryo mortality than the sites of smaller @M @M. Sources of embryo mortality included developmental abnormalities and predation. Choice of oviposition sites included: (a) advance of areas with high water temperatures (>32 degrees C) that result in increased developmental abnormalities and (b) preference for areas that increase embryo survival by increasing developmental rate and/or decreasing efficiency of predation on embryos by the leech. Macrobdella decora.
Vertebrate rod photoreceptors adjust their sensitivity as they adapt during exposure to steady light. Light adaptation prevents the rod from saturating and significantly extends its dynamic range. We examined the time course of the onset of light adaptation in bullfrog rods and compared it with the projected onset of feedback reactions thought to underlie light adaptation on the molecular level. We found that adaptation developed in two distinct temporal phases: (1) a fast phase that operated within seconds after the onset of illumination, which is consistent with most previous reports of a 1–2-s time constant for the onset of adaptation; and (2) a slow phase that engaged over tens of seconds of continuous illumination. The fast phase desensitized the rods as much as 80-fold, and was observed at every light intensity tested. The slow phase was observed only at light intensities that suppressed more than half of the dark current. It provided an additional sensitivity loss of up to 40-fold before the rod saturated. Thus, rods achieved a total degree of adaptation of ∼3,000-fold. Although the fast adaptation is likely to originate from the well characterized Ca2+-dependent feedback mechanisms regulating the activities of several phototransduction cascade components, the molecular mechanism underlying slow adaptation is unclear. We tested the hypothesis that the slow adaptation phase is mediated by cGMP dissociation from noncatalytic binding sites on the cGMP phosphodiesterase, which has been shown to reduce the lifetime of activated phosphodiesterase in vitro. Although cGMP dissociated from the noncatalytic binding sites in intact rods with kinetics approximating that for the slow adaptation phase, this hypothesis was ruled out because the intensity of light required for cGMP dissociation far exceeded that required to evoke the slow phase. Other possible mechanisms are discussed.
Foraging behavior is responsive to changes in predation risk; increased illumination reduces foraging in open areas without cover. Foraging behavior is also affected by resource enrichments. Differences among species in habitat selection are correlated with specific abilities to detect and avoid predators. The least vulnerable species, Dipodomys deserti, foraged heavily in the open and was largely unaffected by treatments; the other species of kangaroo rats and kangaroo mice (D. merriami, D. microps, and Microdipodops pallidus) also prefer the open, but responded to both risk and resource manipulations; highly vulnerable Peromyscus maniculatus was restricted to bushes, even under the best of circumstances; Perognathus longimembris was displaced from preferred microhabitats by the presence of kangaroo rats. Predation risk provides an axis along which habitat segregation occurs. -from Author