Khrushchova A.M., Vasilieva N.Yu., Shekarova O.N., Vasilieva N.A., Rogovin K.A. 2023. Daily torpor in Campbell s hamster (Phodopus campbelli Thomas, 1905) Proximate backgrounds and ultimate fitness consequences // Russian J. Theriol. Vol.22. No.1. P.32–43 [in English].
Anastasia M. Khrushchova [cricetulus@yandex.ru], Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Leninsky prospect 33, Moscow 119071, Russia; Nina Yu. Vasilieva [nyv1@yandex.ru], Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Leninsky prospect 33, Moscow 119071, Russia; Olga N. Shekarova [shekar@mail.ru], Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Leninsky prospect 33, Moscow 119071, Russia; Nina A. Vasilieva [ninavasilieva@gmail.com], Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Leninsky prospect 33, Moscow 119071, Russia; Konstantin A. Rogovin [krogovin@yandex.ru], Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Leninsky prospect 33, Moscow 119071, Russia.
doi: 10.15298/rusjtheriol.22.1.04
ABSTRACT. In 68 pairs of Campbell’s hamster (Phodopus campbelli Thomas, 1905) caged outdoors, under natural day length and temperature, we considered ambient temperatures, body mass and its change as proximate factors of torpor bouts. The ultimate effects of daily torpor were assessed by the mortality of animals and the number of litters born. Both sexes showed daily torpor irregularly from November 2010 to January 2011 with a maximum in December; 37% of males and 39% of females did not show any torpor at all. There was no link between torpor episodes and low ambient temperatures during the whole winter, when considering the total winter period, however, we did find a significant link between ambient temperature and torpor use in December. Daily torpor in Campbell’s hamsters we studied seems not to be an obligate, strictly deterministic physiological response to critical body condition when the body reserves are close to exhaustion. Among males, we observed a tendency towards a positive correlation of the number of torpor bouts on the initial body mass in September. The body mass loss from September to December was positively correlated to September’s body mass. Torpor pattern did not affect the hamsters’ survival and the number of litters born. We conclude that our results do not indicate daily torpor in Campbell’s hamster as an obligate life history adaptation, which should unconditionally enhance ultimate fitness consequences.
KEY WORDS: daily torpor, heterothermia, Campbell’s hamster, Phodopus campbelli, winter biology.