SUMMER TORPOR IN AFRICAN WOODLAND DORMICE GRAPHIURUS-MURINUS (MYOXIDAE, GRAPHIURINAE)

We determined the effect of food availability (presence/absence) and a mbient temperature (25/10 degrees C) on daily energy expenditure and t he use of activity and torpor in summer-acclimated captive Graphiurus murinus. Daily energy expenditure declined logarithmically with durati on of food deprivation at a mean rate of 11 and 31% per day at 25 and 10 degrees C, respectively. The incidence of torpor in the presence of food at 25 degrees C was low (one in seven individuals) and increased on a single day's exposure to 10 degrees C and with duration of food deprivation. Use of torpor was highest during the day, varied between individuals, and torpor bouts of greater than 24 h duration were not n oted. With food deprivation, individuals at 25 degrees C initially res ponded by reducing activity but remained euthermic while the same indi viduals at 10 degrees C responded by increasing their use of torpor du ring the light period; this difference in response probably reflects a difference in the relative energetic benefits of torpor at different temperatures.