Abstract # 5906 Event # 135:

Scheduled for Sunday, September 14, 2014 03:15 PM-03:30 PM: Session 21 (Mary Gay) Oral Presentation


INFLUENCE OF ABIOTIC FACTORS ON CATHEMERAL ACTIVITY AMONG SOUTHERN BAMBOO LEMURS

T. M. Eppley1,2, J. U. Ganzhorn1 and G. Donati2
1University of Hamburg, Department of Animal Ecology and Conservation, Hamburg 20146, Germany, 2Nocturnal Primate Research Group, Oxford Brookes University, Oxford, OX3 0BP, United Kingdom
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     Although rare among primates, cathemerality (i.e., the ability to be active during the day and night) is prevalent among the strepsirrhine family of Lemuridae, potentially representing one of the earliest adaptations of the lemurid radiation. Thus far, only rigorous long-term studies involving the genera Eulemur and Lemur have been conducted, leaving nocturnal activity observations within the genera Hapalemur to remain anecdotal. Our study sought to understand whether southern bamboo lemurs (Hapalemur meridionalis) exhibited a cathemeral activity pattern in the Mandena littoral forest of south-east Madagascar, and to identify which abiotic factors may influence its occurrence. Ten adult H. meridionalis spread across four habituated social groups were captured and fitted with external radio-transmitters with an archival tag (ARC400, Advanced Telemetry Systems) that continuously recorded a proportional rate of activity every fifteen minutes throughout the duration of the study, approximately October 2012 – December 2013. While controlling for a possible influence of astronomical twilight and using a monthly diurnal-to-nocturnal activity ratio and non-parametric statistics, our results show a significant increase in nocturnal activity during nights of greater lunar luminance. Additionally, there is a significant negative correlation between nocturnal activity and increasing temperature. This research provides the first ever longitudinal study of cathemerality among the genus Hapalemur with the data conclusively supporting a diel activity pattern significantly influenced by lunarphilia and seasonality.