Body Mass in Wild Microcebus murinus over the Dry Season

Abstract

The main aim of this field study was to compare adult male and female grey mouse lemurs (Microcebus murinus) with respect to body size, seasonal changes in body mass, onset of reproductive activity and sex ratio of captured animals. M. murinus was studied in the dry deciduous forest of western Madagascar. The lemurs were trapped in capture/recapture sessions during the dry season of 1993 (August, September, October). In order to verify results of studies in captivity concerning body mass and rank order among males, distribution patterns and body mass of males and females were examined. The results of this study indicate that rank in males is related to body mass and testes size, rather than determined by body size. Heavier males occurred closer to females, possibly facilitating access to breeding opportunities. There was no sexual dimorphism in body size. Differences between the sexes in seasonal changes in body mass, and in numbers of each sex caught, indicate that males and females have different activity patterns during the dry period, when food availability is restricted.

Mating system ofMicrocebus murinus

“…In males length and width of one testis were measured. Testis size was maximal during the mating season in October [Fietz, 1998;Schmid & Kappeler, 1998]. Therefore, analysis of relative testis size are based on these data from October.…”

“…Former studies have shown, that even though sexes exhibit independent variations in body mass across seasons [Fietz, 1998;Petter-Rousseaux, 1980;Schmid, 1997;Schmid & Kappeler, 1998], M. murinus lacks sexual size dimorphism concerning various body measurements such as length and width of head and ear, length of body, tail, hindfoot, and canine length [Fietz, 1998;Kappeler, 1997a;Schmid & Kappeler, 1998]. If M. murinus mates polygynously, it would be expected that it exhibits strong sexual size dimorphism, exclusive male territories, and small relative testes size [Cheverud et al, 1985;Clutton-Brock et.…”

Pair-Bonding, Female Aggression and the Evolution of Lemur Societies

“…Males apparently have larger home ranges than females, thus having more potential contacts with a variety of mates. There is so far no indication of longer-term bonding between particular animals [10][11][12]. Information on the social system of the pygmy mouse lemur (Microcebus myoxinus) [13] is not yet available.…”

Costs and Potential Benefits of Parental Care in the Nocturnal Fat-Tailed Dwarf Lemur (Cheirogaleus medius)

“…Body mass was measured to the nearest gram with a 300-gram spring balance (Pesola). Trapped individuals were weighed and head width was measured (for detailed descriptions, see Fietz [1998]). Maximum tail circumference and the tail length were measured.…”

“…In order to be able to compare the quantity of fat stored by different individuals, body condition (= body mass in grams divided by head width in millimetres; following Jenkins and Albrecht [1991] and Fietz [1998]) and tail index (= tail volume in millilitres divided by tail length in millimetres [Fietz et al, 2002]) were calculated. Data on body condition and tail index were pooled for March and April separately over all study years.…”