Welcome to the Dark Side: Partial Nighttime Illumination Affects Night-and Daytime Foraging Behavior of a Small Mammal

Abstract

Differences in natural light conditions caused by changes in moonlight are known to affect perceived predation risk in many nocturnal prey species. As artificial light at night (ALAN) is steadily increasing in space and intensity, it has the potential to change movement and foraging behavior of many species as it might increase perceived predation risk and mask natural light cycles. We investigated if partial nighttime illumination leads to changes in foraging behavior during the night and the subsequent day in a small mammal and whether these changes are related to animal personalities. We subjected bank voles to partial nighttime illumination in a foraging landscape under laboratory conditions and in large grassland enclosures under near natural conditions. We measured giving-up density of food in illuminated and dark artificial seed patches and video recorded the movement of animals. While animals reduced number of visits to illuminated seed patches at night, they increased visits to these patches at the following day compared to dark seed patches. Overall, bold individuals had lower giving-up densities than shy individuals but this difference increased at day in formerly illuminated seed patches. Small mammals thus showed carry-over effects on daytime foraging behavior due to ALAN, i.e., nocturnal illumination has the potential to affect intra- and interspecific interactions during both night and day with possible changes in personality structure within populations and altered predator-prey dynamics.

The moon’s influence on the activity of tropical forest mammals

“…The influence of natural and artificial light is an increasingly important topic in wildlife conservation and ecosystem functioning (Gaston et al 2017, Hirt et al 2023). Yet we still know too little about the implications of artificial light on the activity of mammals (Hoffmann et al 2022). The prevalence of lunar phobia in our study suggests there may be more losers than winners when illumination increases in tropical forests.…”

Insect communities under skyglow: diffuse night-time illuminance induces spatio-temporal shifts in movement and predation

“…Light pollution has been shown to have widespread effects on movement behaviours across several spatial scales, such as migration [19][20][21] and dispersal [22,23], as well as local movements within and between habitats [24][25][26][27]. These effects can be diverse [8]; for instance, at local scales there is evidence of reduced [28][29][30][31] as well as increased movement activity [32] in response to ALAN, which may be induced by the elevated risk or facilitation of predation, respectively.…”

Dark roads aid movement but increase mortality of a generalist herbivore in the American Southwest

“…Artificial nightlight is a significant environmental cue that might affect these perceived trade‐offs. Numerous studies have shown that artificial nightlight can influence wildlife behaviors and movements, for example, by impacting their foraging and hunting strategies (Bennie et al, 2015; Ditmer, Stoner, Francis, et al, 2021; Hoffmann et al, 2022; Shier et al, 2020), movement and migration paths (Bliss‐Ketchum et al, 2016; Cabrera‐Cruz et al, 2018), vigilance behaviors (Yorzinski et al, 2015), physiological stress levels (Bedrosian et al, 2011; Ouyang et al, 2017), and energy budgeting (Touzot et al, 2019). Both increasing and ubiquitous, artificial nightlight emanates from sky glow, headlights, streetlamps, homes, and businesses and disturbs natural light regimes worldwide (Gaston, 2018; Gaston et al, 2014; Kyba et al, 2017; Sánchez de Miguel et al, 2022).…”