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

Research output: Contribution to journalArticle

Abstract

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.

Details

Authors
Organisations
External organisations
  • Indian Institute of Science Education and Research, Thiruvananthapuram
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Zoology

Keywords

  • Ambient light, Flight activity, Moon phases, Pteropodids, Twilight zones
Original languageEnglish
JournalJournal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology
Publication statusE-pub ahead of print - 2021 Feb 3
Publication categoryResearch
Peer-reviewedYes