PARENT SESSION
Poster Session 28: Mammalian Ecology.
Wednesday, August 4 Presentations from 5:00 PM to 6:30 PM, Exhibit Hall A 1.
Diet of live and mummified spotted bats in northern Arizona as indicated by stable isotopes.
Chambers, Carol, Theimer, Tad, Mikesic, David, Painter, Mikele, Doucett, Richard,
ABSTRACT- In 1995, a mummified spotted bat (Euderma maculatum) was discovered in a limestone cave (1,530 m elevation; Great Basin desertscrub vegetation) in northern Arizona. Using radiocarbon analysis, the bat was dated as 9180 ± 50 radiocarbon years old (14C years before present [B.P.]). In 2003, we retrieved 6 additional spotted bat mummies. Remains dated from <50 yrs B.P. to 2110 ± 40 yrs B.P. (approximate ages: <50, 120, 180, 300, 1450, 2110 years B.P.), indicating long-term stable use of the cave roost. We captured live spotted bats roosting in this cave (n = 8) and on the Kaibab Plateau (2500 m elevation, 35 km from the cave, n = 27). We collected hair and wing samples from mummified remains and live bats. Stable isotope signatures from live spotted bats and from the <50 yr B.P. mummified spotted bat were similar. However, mummified spotted bats >50 yrs B.P. were more enriched in carbon suggesting their diet had shifted within the past 100 years from a higher proportion of C4 plant feeding moths to C3 plant feeding moths. We hypothesize that this shift in spotted bat diet could be related to one of several causes: (1) decrease in C4 plant density, (2) increase in C3 plant density, (3) diet shift in spotted bats, (4) isotope enrichment in C3 plants > 100 yrs B.P., or (5) early in the mummification process preservation shifted the isotopic signature which then remained constant for thousands of years.
Key words: diet, stable isotopes, spotted bats, Euderma maculatum