Light, flight and the night: effect of ambient light and moon phase on flight activity of pteropodid bats

TY - JOUR

T1 - Light, flight and the night

T2 - effect of ambient light and moon phase on flight activity of pteropodid bats

AU - Murugavel, Baheerathan

AU - Kelber, Almut

AU - Somanathan, Hema

PY - 2021

Y1 - 2021

N2 - Fruit-feeding pteropodid bats roost under varying light conditions. Some roost in trees with high exposure to daylight (> 1000 lx), while others roost in dark caves (< 0.1 lx). To understand the effect of ambient light intensity and moon phase on flight activity, we examined flight times across five lunar cycles in three pteropodid species whose roosts differ in daylight exposure. We found significant interspecific differences in flight emergence and termination times. All species initiated flights after sunset but Rousettus leschenaultii, which typically roosts in caves, delayed emergence (40 ± 11 min) more than the two tree-roosting species Pteropus giganteus (16 ± 6 min) and Cynopterus sphinx (19 ± 7 min). R. leschenaultii terminated flights earlier (30 ± 7 min before sunrise) than P. giganteus (11 ± 11 min) and C. sphinx (16 ± 10 min). All individuals from P. giganteus and C. sphinx roosts emerged within less than an hour, while emergence times were more spread out in the R. leschenaultii colony. Peak emergence times differed across moon phases in the cave-roosting R. leschenaultii but not in the other species. Flight activity in R. leschenaultii is restricted to comparatively lower light levels than the tree-roosting species. The observed interspecific differences suggest that bat species, sharing same landscapes may respond differently to light pollution.

AB - Fruit-feeding pteropodid bats roost under varying light conditions. Some roost in trees with high exposure to daylight (> 1000 lx), while others roost in dark caves (< 0.1 lx). To understand the effect of ambient light intensity and moon phase on flight activity, we examined flight times across five lunar cycles in three pteropodid species whose roosts differ in daylight exposure. We found significant interspecific differences in flight emergence and termination times. All species initiated flights after sunset but Rousettus leschenaultii, which typically roosts in caves, delayed emergence (40 ± 11 min) more than the two tree-roosting species Pteropus giganteus (16 ± 6 min) and Cynopterus sphinx (19 ± 7 min). R. leschenaultii terminated flights earlier (30 ± 7 min before sunrise) than P. giganteus (11 ± 11 min) and C. sphinx (16 ± 10 min). All individuals from P. giganteus and C. sphinx roosts emerged within less than an hour, while emergence times were more spread out in the R. leschenaultii colony. Peak emergence times differed across moon phases in the cave-roosting R. leschenaultii but not in the other species. Flight activity in R. leschenaultii is restricted to comparatively lower light levels than the tree-roosting species. The observed interspecific differences suggest that bat species, sharing same landscapes may respond differently to light pollution.

KW - Ambient light

KW - Flight activity

KW - Moon phases

KW - Pteropodids

KW - Twilight zones

U2 - 10.1007/s00359-020-01461-3

DO - 10.1007/s00359-020-01461-3

M3 - Article

AN - SCOPUS:85100487290

VL - 207

SP - 59

EP - 68

JO - Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology

JF - Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology

SN - 1432-1351

IS - 1

ER -