Sexual advertisement calls of male mouse lemurs from two neighbouring demes in a dry deciduous forest of western Madagascar were recorded during the breeding season. Demes were located about 1.5 km apart with no geographic barrier between them. They were characterised morphometrically and genotyped by RAPD fingerprinting. According to univariate and multivariate statistical analysis, demes differed neither in body measurements, nor in the banding patterns produced by RAPD fingerprinting. The acoustic pattern of the advertisement call, however, showed significant differences: Six variables of the frequency and time domain differed between the demes. Discriminant function analysis revealed that one variable, total call duration, was sufficient to classify more than 89% of the calls correctly to the corresponding deme. We postulate that these differences are comparable to dialects in birds, because demes were morphologically and genetically indistinguishable and no barrier prevented genetic exchange between them. Possible explanations for the emergence of dialects in a prosimian species are outlined.

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Nocturnal primate species are often difficult to discriminate by gross visual bodily characteristics. This is also true for the world's smallest primate taxon, the Malagasy mouse lemurs. Recent findings imply that this taxon contains sibling species that can be diagnosed noninvasively by their species-specific advertisement call. We used comparative bioacoustics in order to explore variation of this call type and to assess species status of three European colonies. Acoustic variation was compared within and between colonies as well as with known species-specific differences. It was further related to morphological and genetic variations to investigate in how far it covaries with them. Results show that acoustic and genetic differences revealed by random amplified polymorphic DNA (RAPD) fingerprinting separated colonies reliably, but were on a different level than known species-specific differences. A Mantel test showed that acoustic differences were weakly correlated to genetic, but not to morphological differences. Our study is the first to reveal that both acoustic signaling and genetics clearly establish the species status for nocturnal primate populations. It also suggests that acoustic traits change at a more obvious and rapid pace than morphology in isolated populations, and may be used as an indication of conditions that may favor the evolution of subspecies.

Continued survival of most animal species depends on population management and active protection. It is generally agreed that, in order to avoid extinction of endangered species, ex situ and in situ conservation must be developed in tandem. However, even though many recommendations have been put forward to promote the survival of captive populations, some rapidly become extinct due to loss of genetic diversity (drift effect). Genetic markers, such as random amplified polymorphic DNA (RAPD) markers, can be applied to rapid testing of many individuals. They also permit analysis of very small amounts of DNA, when small species such as mouse lemurs (Microcebus) are to be tested. Using RAPD markers, we compare genetic diversity in four captive groups of Microcebus murinus to that in a sample of 70 wild mouse lemurs. Following the principles of Mendelian inheritance, each amplified fragment of DNA may be considered as a ‘locus’ (or an amplifying site). The series of bands amplified by a particular primer in any individual is referred to as the individual’s ‘profile’. We tested 5 primers, or, in the above terms, we studied 98 different ‘loci’. Results showed that the captive groups had lost genetic information with respect to the wild sample. Among the four captive groups, the loss of genetic diversity varied according to their number of founders and/or the management of their captive reproduction. Our study of polymorphism permitted us to establish tools for the genetic management of captive breeding, and for the determination of paternity which frequently give better results than behavioural studies; and simulation of introductions or departures of individuals in one very monomorphic group permitted estimation of future increases in its genetic diversity.

HAFEN, T. AND F. WOLLNIK. Effect of lithium carbonate on activity level and circadian period in different strains of rats. PHARMACOL BIOCHEM BEHAV 49(4) [975][976][977][978][979][980][981][982][983] 1994.-Lithium, an important pharmacological agent for the treatment of manic-depressive illness in humans, is known to lengthen the circadian period in a number of different species. Recent experiments, on the other hand, suggest that pharmacological agents may affect the circadian system indirectly through an increase or decrease of activity. To explore the interaction between pharmacological and activity effects on the circadian system, lithium was administered chronically to three different strains of rats (ACI, BH, and LEW) while wheel-running activity was studied quantitatively. Two of these inbred strains (BH and LEW) show profound abnormalities in their circadian activity rhythms, namely, a reduced overall level of activity and bimodal or multimodal activity patterns. Wheel-running activity was monitored for 4 weeks under baseline conditions, followed by 3 weeks with lithium treatment (0.3% Li 2 C0 1 administered with food) and 4 weeks with normal food. Treatment with lithium (average intake per day = 3.6 ± 0.2 mg) consistently decreased both the overall level and the circadian amplitude of the activity rhythm. The free-running period r was slightly lengthened during lithium treatment, while the most dramatic effect on period was observed after lithium withdrawal. Correlation analysis, however, revealed only a small negative correlation between activity level and period length, which proved significant only for animals of the ACI strain. Our data support the traditional interpretation that lithium lengthens circadian period by a direct pharmacological effect on the circadian pacemaker rather than through indirect effects of activity feedback. to the effect that the therapeutic effect of these drugs may be based on their phase delaying effect on the circadian pacemaker. So far, the mechanisms responsible for lithium's chronopharmacological actions are not known. It has been suggested that lithium could lengthen the circadian period by a) slowing of cellular oscillators, b) by altering the coupling between multiple circadian oscillators, or c) by altering light sensitivity (17). The hypothesis that lithium may weaken the mutual interaction between multiple oscillators is especially intriguing because modifications in coupling strength could theoretically account for changes in period, as well as entrained phase, wave form, and amplitude of circadian rhythms. Circadian rhythmsThe period-lengthening effect of lithium is of special interest with respect to the hypothesis that there may be an association between the pathophysiology of affective disorders and disturbances of circadian rhythms (22,48). Several studies in humans have demonstrated that many circadian rhythms are phase advanced in depressed patients compared to controls [reviewed in (12,44,45)]. Because lithium and a few other antidepressant agents (5,47...