Non-invasive monitoring of reproductive status in wild mongoose lemurs (Eulemur mongoz)

Abstract

Endocrine profiles were investigated in wild and captive mongoose lemurs(Eulemur mongoz; Lemuridae) by analysing faecalprogestagens and oestrogens. Oestrous cycle characterization was not possible,as most females appeared to conceive during the first oestrus of the breedingseason. Conception was preceded by a pseudo-oestrus with no discernible lutealphase. Pseudo-oestrus and oestrus identification was possible by investigatingthe oestrogen : progestagen ratio. Pregnancy was reliably determinedapproximately 47 days after conception, when progestagen and oestrogenexcretion increased above breeding season concentrations. Gestation wasfurther characterized by high progestagen concentrations and a decline inoestrogen excretion 70-80 days after conception. Post partum,progestagens declined, but oestrogen excretion increased to exceed breedingseason concentrations. In the wild group, a nulliparous daughter conceivedwhile still a member of her natal group and aborted after 70-80 days ofpregnancy at which time progestagens had declined but oestrogens remainedhigh. Comparisons with other strepsirhine primates suggest that pseudo-oestrusfollowed by conception at first oestrus may be prevalent in lemurs.Gestational progesterone profiles vary between species, but a delayed increasein oestrogens during pregnancy could be common to all strepsirhines, althoughoestrogen levels during the final trimester of pregnancy differ between lemursand lorises. Methodological investigations showed that prolonged storage offaeces in ethanol is viable and that the presence of undigested vegetablematter in the faecal pellets had no effect on the interpretation of hormoneprofiles.