Meeting Abstract
P1.10 Sunday, Jan. 4 Do parasites and body condition explain variation in anti-predator vigilance? BLUMSTEIN, D.T.; CHMURA, H.E.*; WEY, T.; Univ. of California, Los Angeles; Swarthmore College; Univ. of California, Los Angeles hchmura1@swarthmore.edu
Most animals must allocate some time to anti-predator vigilance. While hundreds of studies have examined antipredator vigilance in birds and mammals, much variation in vigilance remains unexplained. Prior research in marmots indicates that anti-predator vigilance is sensitive to environmental factors such as incline and vegetation height. We examined whether internal factors might also explain variation in anti-predator vigilance. We studied yellow-bellied marmots (Marmota flaviventris), a large ground squirrel found in alpine and subalpine areas of Western North America. Adult and yearling marmots were live-trapped at Rocky Mountain Biological Laboratory (RMBL), Gunnison County, Colorado, USA during spring and summer months from 2004 to 2008 and sampled for blood, fecal and ectoparasites. Body condition was measured as the residual of a general linear model with mass as the dependent variable and age, sex, colony, year and time of season as independent variables. We quantified vigilance behavior in foraging marmots during 2 minute focal samples taken during the early morning (06:00-11:00) and late afternoon (15:00-19:00) from late April to mid-August. We fitted general linear models to explain variation in three measures of marmot vigilance. We found that increases in body condition corresponded with decreases in each measure of marmot vigilance. Marmots infected with Entamoeba, an intestinal parasite, tended to spend a greater proportion of time vigilant. By contrast, marmots infected with Eimeria, an intestinal parasite, or Trypanosoma, a blood parasite, tended to decrease average vigilance bout duration. Our results suggest that some variation in vigilance is explained by internal condition and parasites; however, substantial variation remains unexplained.
