94th ESA Annual Meeting (August 2 -- 7, 2009)

COS 99-2 - Effects of caudal autotomy on the escape behaviors of two Sceloporus lizards, S. jarrovii and S. virgatus

Thursday, August 6, 2009: 1:50 PM
Taos, Albuquerque Convention Center
Christopher R. Agard1, Michael J Cericola1, Constance Trower1, Joel Smoot2 and George Middendorf1, (1)Biology, Howard University, Washington, DC, (2)Zoology, University of Wisconsin-Madison, Madison, WI
Background/Question/Methods

On average, the ratio of tail-length (TL) to body-length (SVL) is greater in S. jarrovii than in its sympatric congener, S. virgatus, which rarely climbs, suggesting that the TL may have some role adapting S. jarrovii to scansorial life and that reduction may reduce the fitness.  Vertical run-speed (VRS) and aerial-righting success (ARS) are characteristics we assume to be positively related to survival.  To examine the effect of CA on both, we examined 1) time required for a lizard to complete a vertical route when pursued and 2) likelihood of a lizard to landing “on its feet” (ventrum down) when dropped from a supine position.  Our hypotheses were that CA would diminish the lizard’s ability to right itself and impair running ability.  We tested two treatments of both S. jarrovii and S. virgatus.

Results/Conclusions

We found that CA significantly reduced righting success in S. jarrovii, but did not affect S. virgatus.  Results for the vertical run speed analyses do not appear to show a clear effect in either species.