April and June, 2014. UCSC. Thermal preferences and parasites of Sceloporus occidentalis bocourtii.

We captured 77 adult (males = 47, females = 30) coast range fence lizards, Sceloporus occidentalis bocourtii (Squamata: Phrynosomatidae), at Santa Cruz County, CA, USA (36.9852, -122.0614) during two sampling campaigns in 2014. In mid April we captured 42 lizards and in early June 35 lizards. All lizards were caught using a noose and were transported to the lab facilities in a cooler. The sex of the individuals was determined by the presence of enlarged post-anal scales (Cox et al., 2005; Megía-Palma et al., 2018). Snout to vent length (SVL) of the lizards was measured with a ruler to the nearest millimeter and their mass to the nearest gram using a digital scale. A body condition index was estimated using the Scaled Mass index (SMi). This estimation accounts for the growth effect on body size as well as for the scaling relationship between mass and body length (Peig and Green, 2009; 2010), and it is calculated using the standardized major-axis of the mass on body length (following Bohonak, 2004). A second mass measurement of the lizards captured in April (N = 42) was taken 11 days post-capture. Thus, during this period, the lizards were housed individually in plastic terraria with a damp substrate of peat moss and sand, and were provided with water and food (crickets dusted with vitamins and calcium) ad libitum. The terraria were kept in an environmental chamber with a 12L:12D photoperiod provided by natural spectrum fluorescent and ultraviolet lights and a cycling thermal regime. We used one empty terrarium with substrate to register standard temperatures 24 h/day every 5 minutes during 11 days with a data logger (hobo U23-002, Onset, Cape Cod, Massachusetts, USA). We set one probe of the data logger in one corner of the cage under the heat source (i.e., 40 Watt bulb) and other probe in the opposite corner. Within two days of capture lizards were allowed to select temperatures in experimental thermal gradients (i.e., 48-25 ºC) and their body temperature was recorded every minute during the 120 minute trial (as in Paranjpe et al., 2013). Preferred temperature (Tp) was later calculated as the arithmetic mean of measured body temperatures (Pough and Gans, 1982). Standard deviations of body temperatures (SD) were also calculated. Thus, lizards with high SD have low precision of thermoregulation (Paranjpe et al., 2013). Maximum and minimum body temperatures of each individual were also registered as measures of voluntarily selected temperatures (Tmax.v, and Tmin.v). In addition to these measurements of thermal preference, we also investigated the parasitic infections of these lizards. Tick load was quantified within the first day of capture and at day 11 by the same person (RM-P). In addition, following the methods described in Megía-Palma et al. (2018), the same person (RM-P) diagnosed chronic infections by hematic (i.e., Lankesterella occidentalis) and intestinal (i.e., Acroeimeria sceloporis) coccidians only once at the beginning of the trials.本研究于2014年在美国加利福尼亚州圣克鲁斯县（坐标36.9852, -122.0614）开展两次采样活动，共捕获77只成体海岸栅栏蜥（Sceloporus occidentalis bocourtii，有鳞目Squamata、棘蜥科Phrynosomatidae），其中雄性47只、雌性30只。2014年4月中旬捕获42只，6月初捕获35只。所有个体均采用活套诱捕，并通过冷藏箱转运至实验室设施。个体性别通过肛后鳞片是否膨大进行判定（Cox等，2005；Megía-Palma等，2018）。用直尺测量个体吻肛长（Snout to Vent Length, SVL），精确至1毫米；使用电子天平称量体重，精确至1克。采用标准化质量指数（Scaled Mass Index, SMi）估算身体状况指数：该指数可校正体型生长对身体质量的影响，并考量体重与体长间的异速生长关系（Peig & Green, 2009；2010），计算时采用体重对体长的标准主轴回归方法（参照Bohonak, 2004）。对4月捕获的42只个体，在捕获后第11天开展第二次体重测量。饲养期间，所有个体均单独饲养于塑料爬宠饲养箱中，箱内铺设由泥炭藓与细沙混合制成的湿润垫料，并自由提供饮水及添加维生素与钙粉的蟋蟀作为食物。爬宠饲养箱放置于环境控制舱内，采用自然光谱荧光灯与紫外灯提供12小时光照:12小时黑暗的光周期，并设置周期性温度变化制度。本研究使用一只铺设有相同垫料的空爬宠饲养箱，通过数据记录仪（hobo U23-002，Onset公司，美国马萨诸塞州科德角）连续11天、每5分钟记录一次箱内温度，实现24小时不间断监测；记录仪的两个探头分别放置于爬宠箱热源（即40瓦灯泡）下方的角落，以及对角的另一角落。 捕获后两天内，将蜥蜴放置于48~25℃的实验温度梯度箱中允许其自主选择体温，并在120分钟的实验过程中每分钟记录一次个体体温（参照Paranjpe等，2013）。后续以所有实测体温的算术平均值计算偏好体温（Preferred Temperature, Tp）（Pough & Gans, 1982），同时计算体温的标准差（Standard Deviation, SD）：标准差越高，代表个体的体温调节精度越低（Paranjpe等，2013）。此外还记录每只个体的最高与最低自主选择体温，分别记为Tmax.v与Tmin.v。除上述体温偏好相关测量外，本研究同时对蜥蜴的寄生虫感染情况开展了调查：由同一研究者（RM-P）分别在捕获当日及第11天对蜱虫寄生负荷进行计数；参照Megía-Palma等（2018）的方法，该研究者（RM-P）仅在实验开始时对个体的血液寄生性球虫（Lankesterella occidentalis）与肠道寄生性球虫（Acroeimeria sceloporis）的慢性感染情况进行一次诊断。