Female Reproduction in Flat-tailed Horned Lizards (Phrynosoma mcallii)

Pawlicki, Anthony

School of Natural Resources and the Environment

University of Arizona

Tucson, AZ USA


Hawkins, Allyson

University of Kent

Canterbury, UK

Goode, Matt

School of Natural Resources and the Environment

University of Arizona Tucson, AZ

We investigated reproduction in female Flat-tailed Horned Lizards (Phrynosoma mcallii) on the Barry M. Goldwater Bombing Range near Yuma, Arizona. We palpated and weighed females to determine gravidity. We affixed radio transmitters to the dorsal surface of lizards using silicone adhesive. We radio tracked individuals two to three times per day until they laid their eggs. We placed nest enclosures around nest burrows using aluminum flashing and we checked the enclosures daily until hatchlings appeared or ten weeks had passed. We radio tracked 29 individual females from mid-May until late September, three of which we tracked over two separate time periods. Sixteen individuals produced one clutch, and two individuals produced two clutches. Females moved relatively long distances prior to oviposition, which may be a dispersal mechanism leading to increased genetic diversity. Upon exiting nest burrows, females backfilled the entrance to their burrows (14 of 19 exhibited this behavior). Hatchlings emerged from nest burrows approximately six weeks after oviposition. Although we were unable to reliably determine the number of eggs laid, the number of hatchlings that emerged from nests ranged from 1-6. We will continue to examine reproduction at our study site in 2018. We plan to use a field-portable ultrasound device to obtain accurate data on number of ova. We also hope to gain a better understanding of reproductive output by determining the frequency and timing of multiple clutches. In addition to demographic and life history data, we are also examining population ecology, dispersal, and parentage using genomic analyses.