Torpor use during gestation and lactation in a primate

Area of Science:

• Physiology
• Zoology
• Ecology

Background:

• Torpor is an energy-saving strategy for endotherms facing energetic challenges.
• Reproduction typically requires high energy expenditure, making torpor use seem incompatible with offspring development.

Purpose of the Study:

• To investigate if heterothermic primates utilize torpor during gestation and lactation to cope with food scarcity.
• To assess the energetic consequences of torpor use during reproduction in female grey mouse lemurs (Microcebus murinus).

Main Methods:

• Reproductive female grey mouse lemurs were subjected to varying degrees of food restriction (0%, 40%, 80%).
• Torpor was monitored using daily skin temperature profiles.
• Energetic outcomes were evaluated by measuring changes in body mass.

Main Results:

• Food shortage induced torpor during late gestation, with severity correlating to restriction level.
• During lactation, 80% food restriction led to increased torpor frequency and depth, prioritizing maternal energy saving.
• Despite torpor, 80% restriction resulted in maternal mass loss and impaired pup growth.

Conclusions:

• This study presents the first evidence of torpor use in a heterothermic primate during reproduction to mitigate food shortages.
• While torpor offers physiological flexibility, it was insufficient to fully compensate for extreme nutritional deficits during lactation.
• This adaptive capacity likely evolved in response to Madagascar's fluctuating, climate-driven food availability.