Meeting Abstract
P3.20 Wednesday, Jan. 6 There’s no place like home: dispersal and homing behavior of the chuckwalla in southern Nevada HAGERTY, B.E.*; TRACY, C.R.; SANDMEIER, F.; University of Nevada, Reno; University of Nevada, Reno; University of Nevada, Reno bh@biodiversity.unr.edu
Animal movement has both short-term (feeding, maintenance, predation avoidance) and long-term (inbreeding avoidance, reproduction, and survival) implications for individuals and populations. We are using inferences from genetic markers as well as homing experiments to investigate dispersal patterns and homing ability of chuckwallas (Sauromalus ater) in southern Nevada. Chuckwallas are large, saxicolous lizards that are confined to rocky outcrops. Heterogeneous habitat has likely contributed to isolation of chuckwalla populations. Evidence from mitochondrial DNA sequences suggests that chuckwallas expanded into Nevada at the end of the last pluvial period (ca. 10,000 ya), and subsequently little-to-no gene flow has occurred among patches of suitable habitat. Although unique haplotypes occur in populations on most mountain ranges in Nevada, providing evidence that dispersal and gene flow is restricted, this pattern may only be relevant for females as inferences have so far been made from maternally inherited markers. We hypothesize that females may have very limited dispersal, and that males may have a higher propensity to disperse due to their territorial behavior that includes defense of multiple females. We predicted that males would exhibit better navigational abilities during homing than would females. To test this prediction, we displaced female and male chuckwallas, which were outfitted with radio transmitters, at incrementally longer distances from their home sites. Preliminary movement data provide some support for our prediction, although individual variation in responses to displacement is high. Additionally, both sexes exhibit different strategies in response to displacement ranging from extreme searching movements to minimal movement and settlement in new suitable habitat.
