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IPS Conference 2006
Abstracts
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Abstract # 6:
Scheduled for Monday,
June 26, 2006
02:20 PM-02:40 PM:
Session 1 (Kuku)
Symposium
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VARYING EFFECTS OF MOONLIGHT LEVELS ON ACTIVITY BUDGET, SUBSTRATE HEIGHTS USED, AND CALLING OF LEPILEMUR LEUCOPUS AT BEZA MAHAFALY SPECIAL RESERVE, MADAGASCAR – ANTIPREDATION RESPONSES? |
L. T. Nash
Arizona State University, School Human Evolution and Social Change, Box 872402, Tempe, AZ, 85287-2402, USA |
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| Many small mammals, especially rodents, reduce activity when moonlight is brighter and experience more predation at such times. In contrast, some nocturnal primates show increased activity with more moonlight, but little is known about nocturnal lemurs. Adult Lepilemur leucopus (1 female, 6 males) were radio-tracked in riverine forest for focal follow observations across 7 months for about 50 hrs/individual. Activity budget and substrate height were assessed at 5 min point samples. Calling was measured as (1) focal’s calls as 1/0 scores within 5 min intervals, and, (2) an index of amount of calling by other Lepilemur in the focal’s vicinity. Moonlight level was measured relative to both moon phase and moon rise/set times. Activity budget did not change with moonlight level. Animals spent more time in the highest substrates during dark moon times (p<0.05). Calling by focal individuals did not change with moonlight level, but the index of calling in the focal’s vicinity was greater when the moon was bright (P<0.05). Lepilemur’s folivorous diet may constrain energy available for activity budget changes. Highest tree zones may expose animals to visual aerial predators, e.g. owls. Risks of attracting predators by calling (or moving) more during bright moon may be offset by primates’ visual ability to detect them. Moonlight effects should be studied in more nocturnal primate species. Supported by National Geographic Society and Wenner-Gren Foundation. |
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Modified: 18 December 2005
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