VARIATION IN BIRTH RATES AND BIRTH SEASONS AMONG EULEMUR RUBRIVENTER LIVING IN A SELECTIVELY LOGGED REGION OF RANOMAFANA NATIONAL PARK, MADAGASCAR |
| D. Durham Animal Behavior Graduate Group - UCD, Animal Behavior Graduate Group, Univ. of California, One Shields Ave., Davis, CA, 95616, USA |
 |
| The constraints of seasonal breeding potentially limit the ability of threatened lemur populations to stabilize or recover when poor physical condition or habitat perturbation impair reproduction during their short breeding season. From 1999-2001 I studied the reproductive performance of female red-bellied lemurs (Eulemur rubriventer) ('99-'00, n=6; '01 n=5) living within a selectively logged region of Ranomafana National Park, Madagascar. The timing and number of births varied annually. In '99, 83% of females gave birth and all births were detected between Aug 21 and Sep 14. In 2001, 100% of females gave birth, but births were distributed more widely, between Sep 11 and Oct 24. In 2000, however, only 2 females (33%) were seen with neonates; both detected "out of season" (Nov 20; Dec 4). Three cyclones hit in early 2000, giving rise to a marked increase in annual rainfall and subsequent decrease in fruit availability. The clear shift in timing of births following the cyclones of 2000 suggests the possibility of delayed estrus or a post-partum estrus following neonatal loss. This three-year distribution of births is evidence that red-bellied lemurs are not as strictly seasonal as previously suggested. Furthermore, the reported flexibility in the timing of reproduction, potentially reflecting a state-dependent reproductive strategy, could reduce the risk of local extinction by allowing this population sustain or grow under a wide variety of environmental conditions. |
|
|
