Thermoregulation and diurnal roost selection of boreal bats during pre-hibernation period

Kati Marie Suominen, Niclas R. Fritzén, Mari Aas Fjelldal, Anna Sofia Blomberg, Minna Johanna Katariina Viljamaa, Thomas M. Lilley

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Living in a seasonal environment poses challenges for small mammals, such as bats, relianton insects as their primary food source. Bats may adeptly navigate these energetic challenges by reducing their metabolism and body temperature, entering a state of torpor. Particularly during the winter, bats remain torpid for extended periods but are dependent on sufficient energy reserves to survive until spring. With the onset of autumn and declining temperature, bats face the challenge of building their fat deposits during a time of decreasing food availability. Bats may therefore transition to cooler roosts to initiate torpor, thereby reducing energy expenditure. However, little is still known about torpor use or roost selection by bats in autumn. This study explores the factors influencing roost selection and the use and duration of torpor in two bat species during this critical transition period between the breeding and overwintering season. We show that date in autumn is a stronger driver of torpor use than prevailing ambient temperature, indicating that there are other temporal changes (e.g. insect availability, individual body mass) affecting torpor use than solely day-to-day temperature conditions. We also show that bats employ specific strategies in which they first increase daytime torpor use before also increasing the use of night-
time torpor during the pre-hibernation fattening period, most likely to facilitate rapid fat accumulation. Notably, bats commenced night-time torpor use after spending entire days in torpor. These findings underscore the dynamic nature of torpor and the energy-saving strategies employed during the crucial pre-hibernation period, marking the transition from summer to winter
Original languageEnglish
Article numbere10827
JournalOikos
Number of pages11
ISSN0030-1299
DOIs
Publication statusPublished - 5 Dec 2024
MoE publication typeA1 Journal article-refereed

Fields of Science

  • 1181 Ecology, evolutionary biology
  • Autumn
  • Bats
  • Boreal zone
  • Pre-hibernation fattening
  • Seasonality
  • Torpor

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