Meeting Abstract

P3.96  Saturday, Jan. 5  Using Portable Ultrasonography to Examine the Dynamics of Reproduction in Neotoma lepida in Death Valley, CA MATHIASEN, Cindy C*; MURRAY, Ian; WOLF, Blair O; SMITH, Felisa A; University of New Mexico; University of New Mexico; University of New Mexico; University of New Mexico csquared@unm.edu

Field study methodologies quantifying maternal reproductive effort in small mammals have traditionally required destructive procedures to obtain data on basic reproductive parameters such as gestational stage, in-utero litter size, and embryonic or fetal dimensions. Removal of individuals from study population necessarily alters the fundamental group structure and likely affects the very interactions that affect reproductive output. We demonstrate the utility of portable ultrasonography as a non-destructive technique for quantifying reproductive effort without altering the group structure and dynamics in a population of Neotoma lepida in Death Valley, CA. Using a SonoSite Titan portable ultrasound imaging unit we obtained in-vivo virtual measurements of reproductive parameters under strenuous field conditions. This method allows for repetitive sampling of individuals over differing times scales, and allows the progressive quantification of energy invested in a single reproductive event, within a reproductive season or throughout an individual�s lifetime. We conducted time-series ultrasound scans on live-trapped Neotoma lepida females in Death Valley, CA. Progressive scans conducted 2-4 weeks apart suggest females begin reproductive activity in late February or early March and carry litters of 1-4 pups per gestational event. Combining litter size data obtained via ultrasound scans, virtual measurements of in-vivo fetal dimensions, and differential female masses from subsequent trapping events, we demonstrate how this non-destructive technique is essential in elucidating complex interactions between body size, temperature and reproduction.