2.1 Study system, sites and collection of lizards
The Mongolian racerunner (E. argus ), a relatively small (up to
70mm snout-vent length [SVL]) oviparous lacertid lizard, is widely
distributed across China and its environs (Zhao, 1999). the Mongolian
racerunner has been reported across the north‐northeast to the south
(Jiangsu) and the west (Qinghai) of China (Zhao, 1999). Across the
Chinese borders, the Mongolian racerunner has also been reported around
the region of Lake Baikal in Russia, Mongolia, and Korea (Zhao et al.,
2011) within grassland and farmland habitats and arid and semiarid
regions (Zhao, 1999). Mongolian racerunners are widely distributed
across altitude in China (Fig. 1), ranging from sea level to ca. 3000 m
asl (Zhao et al., 1999). The Mongolian racerunner lizard populations
across China are relatively homogeneous in their genetic structure (Zhao
et al., 2011) but show significant variation in morphology, physiology,
life histories, and feeding habits across geographic gradients (Wang et
al., 2020).
We collected 432 female E. argus lizards between 2011 through
2021 from nine field locations across China, varying in altitude and
environmental conditions (Fig. 1). During our field studies from May to
July each year, we collected only non-gravid female E. arguslizards and transported them to
field stations in the study areas. We measured the snout-vent length
(SVL; ±0.01 mm) of collected female lizards in the field station
laboratory, after which we
released them at the site from where they were captured. We collected
and measured the body sizes of E. argus female lizards across
populations with altitudinal gradients ranging from 30 – 2979m above
sea level (asl), with 60 records from Shidu, 26 from Xingtai, 14 from
Jingtai, 36 from Harbin, 31 from Hebei, 25 from Liaoyang, 44 from
Chuzhou, 106 from Erdos, and 90 from
Gonghe (Table S1).