Can bats sense smoke during deep torpor?

Area of Science:

• Animal Physiology
• Ecology
• Conservation Biology

Background:

• Torpor is an energy-saving strategy for animals, but it can impair responses to external stimuli.
• Escaping threats like fire is critical for survival, especially for flying animals like bats.
• Understanding how torpid bats react to environmental cues is vital for their conservation.

Purpose of the Study:

• To determine if torpid bats can sense smoke.
• To investigate the temperature-dependency of torpid bats' reaction time, respiration rate (RR), and heart rate (HR) to smoke.
• To assess the implications for fire management strategies.

Main Methods:

• Quantified RR and HR of captive Australian tree-roosting bats (Nyctophilus gouldi) in torpor.
• Exposed bats to smoke from Eucalyptus spp. leaves at ambient temperatures (T_a) ranging from 11°C to 23°C.
• Measured reaction times and physiological responses to smoke introduction.

Main Results:

• Bats at lower T_a (<15°C) exhibited significantly longer reaction times (28-fold increase) to smoke compared to those at higher T_a.
• Lower T_a bats returned to torpor more swiftly post-exposure but did not always resume steady-state torpor.
• Bats at all tested temperatures responded to smoke, indicating sensory perception even in deep torpor.

Conclusions:

• Torpid bats can detect smoke, but their ability to respond is temperature-dependent.
• Lower ambient temperatures impair bats' rapid escape responses to fire cues, posing risks during winter fire management.
• Conservation efforts and fire management practices should consider the thermal sensitivity of torpid bats' responses to environmental threats.