Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2025 Jul:131:104168.
doi: 10.1016/j.jtherbio.2025.104168. Epub 2025 Jun 13.

Food restricted southern blossom bats (Syconycteris australis) reduce energy use and body temperature

Sharon L McGavin  1 , Zenon J Czenze  2 , Gerhard Körtner  2 , Chris B Wacker  2 , Fritz Geiser  2
Affiliations
Free article

Food restricted southern blossom bats (Syconycteris australis) reduce energy use and body temperature

Sharon L McGavin et al. J Therm Biol. 2025 Jul.
Free article

Abstract

The southern blossom bat (Syconycteris australis) is a small (∼18 g), solitary, tree roosting pteropodid, which forages on nectar, pollen, and small fruits. In Australia, the distribution of S. australis extends along the eastern coast from the tropics to subtropical northern New South Wales (NSW). In NSW, Banksia spp. are an important food source for the species. S. australis can lower metabolic rate (MR) and body temperature (Tb) in a controlled manner to save energy and combat short-term food shortage. While it is known that in S. australis torpor use may vary by season, specifically how ambient temperature (Ta) and food availability influence torpor induction is not understood. Our study therefore aimed to provide the first quantitative examination of the relationships between food availability/restriction, Ta, Tb, and energy expenditure in captive male S. australis. To this end, the relationship between Ta (17-37 °C) and diet ('fed'/'unfed') to subcutaneous temperature (Tsub) and MR was examined using flow-through respirometry (in S. australis Tsub is normally within 0.6 °C of Tb). At Ta < 25 °C, mean resting MR and Tsub were consistently lower in 'unfed' compared with 'fed' S. australis. Below the thermoneutral zone (i.e. below Ta ∼30 °C), the effect of Ta on Tsub depended on food availability, with Tsub decreasing at 0.25 × Ta in 'unfed' bats but at only 0.05 × Ta in 'fed' bats. In contrast, above the thermoneutral zone, Tsub rapidly increased with Ta regardless of feeding treatment (at 0.9 × Ta in 'fed' and 1.0 × Ta in 'unfed' bats). The results demonstrate that under a mild thermal challenge, food availability, rather than Ta, is fundamental in determining whether S. australis reduces MR and Tb. The ability for regulated Tb reductions in response to food restriction is likely crucial for survival of S. australis.

Keywords: Food availability; Megabat; Metabolic rate; Nectarivorous; Torpor.

PubMed Disclaimer

Conflict of interest statement

Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

LinkOut - more resources