Data from: Developmental timing of extreme temperature events (heat waves) disrupts host-parasitoid interactions

The current study consisted of two experiments: one determining how parasitoid sensitivity to heat shock varies across ontogeny (developmental timing experiment), and the other investigating the effects of heat shock temperature and number of heat shock exposures on C. congregata survival and development early in parasitization (temperature/duration experiment). The rearing treatment was the same for both experiments (25°C±10°C), and has been determined to be non-stressful for both parasitoid and host (Moore et al., 2021). The temperature/duration experiment was conducted in January—April, 2018, and the developmental timing experiment took place in October—December, 2018. Organisms were housed in climate control chambers (Percival Scientific 36VL) under 14L/10D hour light cycle. An open container of water was placed in each chamber to prevent desiccation of organisms or artificial diet (Moore et al., 2020). Newly hatched caterpillars were reared on an artificial diet in communal petri dishes until the molt to the 3rd instar. On the day of the molt to 3rd instar (day 0), caterpillars were assigned a unique ID, allocated to a heat shock treatment, weighed, parasitized, and housed individually in small petri dishes. Caterpillars were parasitized by exposing individual caterpillars to a colony of adult wasps, and observing until an oviposition event of >2-3 seconds occurred. The development timing experiment consisted of three heat shock treatments and one control. The heat shock regime was the same for all treatments: three days at 31°C±11°C (daily maximum of 42°C). Recent work has shown that a single exposure to this heat wave regime does not reduce survival, development time or pupal mass of unparasitized M. sexta regardless of developmental stage (Kingsolver et al., 2021). The treatments differed in the developmental stage of the parasitoid larvae at which they experienced the heat shock temperatures (recall that caterpillars in all treatments were parasitized). Early Heat Shock started on day 0 of the 3rd instar, the same day as oviposition; the Middle Heat Shock treatment started 5 days after oviposition (when the majority of C. congregata eggs have hatched); the Late Heat Shock started on day 1 of the host 5th instar (when the majority of C. congregata larvae have molted to the 2nd instar), which ranged from 8-12 days after oviposition. Sample sizes for each treatment ranged from 30-60 parasitized M. sexta caterpillars (see SOM). Individuals in heat shock treatments were transferred to the heat shock chamber at least 2 hours before the DMT, and were removed at 4-5pm on the last day of the heat shock treatment. Parasitized hosts in the control treatment remained in the rearing temperature throughout development. The temperature/duration experiment consisted of a 2x4 factorial design plus one control treatment for a total of 9 treatment combinations. All M. sexta caterpillars were parasitized for this experiment. Parasitized M. sexta were exposed to one of two fluctuating heat shock temperatures, one with a daily maximum temperature of 40°C (30°C±10°C) and the other with a DMT of 42°C (31°C±11°C). Both temperature treatments ramped continuously between 2-hour periods at the high and low temperatures in a 24-hour cycle. Parasitized M. sexta were placed in a heat shock treatment on the same day as oviposition, at least 2 hours before the daily maximum temperature. Experimental insects remained in the heat shock treatments for 1, 2, 3, or 4 days (i.e. they experienced the DMT 1-4 times). Caterpillars were removed from the heat shock treatment at 4 pm – 5pm on the day of their last heat shock, and then returned to the 25°C±10°C rearing treatment. Parasitized hosts in the control treatment remained in the rearing temperature throughout development. The data has been cleaned to remove most erroneous values, though some data cleaning is also required in the R scripts provided. Dates have been converted to Julian day, and life history metrics have been calculated.本研究包含两项实验：其一旨在探明寄生性天敌（parasitoid）对热激（heat shock）的敏感性如何随个体发育（ontogeny）进程变化，即发育时序实验（developmental timing experiment）；其二则探究热激温度与热激次数对寄生早期的C. congregata存活与发育的影响，即温度/时长实验（temperature/duration experiment）。 两项实验的饲养条件完全一致：饲养温度为25℃±10℃，且已有研究证实该温度对寄生性天敌与宿主均无胁迫效应（Moore等，2021）。温度/时长实验于2018年1—4月开展，发育时序实验则于2018年10—12月进行。 所有供试生物均饲养于Percival Scientific 36VL型人工气候箱中，光照周期设置为14小时光照/10小时黑暗。每个气候箱内均放置敞口水盆，以防止供试生物与人工饲料失水干燥（Moore等，2020）。 初孵幼虫以人工饲料为食，于共用培养皿中饲养至蜕皮进入3龄。在蜕皮进入3龄当日（记为第0天），研究人员为幼虫分配唯一标识、分组至不同热激处理组、称量体重、进行寄生处理，并将其单独饲养于小型培养皿中。 寄生处理方式为：将单头幼虫置于成年寄生蜂种群中，持续观察直至寄生蜂完成时长超过2~3秒的产卵行为。发育时序实验包含3个热激处理组与1个对照组。所有处理组的热激方案完全一致：在31℃±11℃的条件下处理3天（每日最高温度为42℃）。 已有最新研究表明，无论发育阶段如何，单次暴露于该热激周期均不会降低未被寄生的烟草天蛾（Manduca sexta, M. sexta）的存活率、发育时长与蛹重（Kingsolver等，2021）。各处理组的差异仅在于寄生性天敌幼虫遭遇热激的发育阶段不同（需注意：所有处理组的幼虫均已完成寄生）。 早期热激组始于3龄第0天，即寄生产卵当日；中期热激组始于产卵后5天（此时绝大多数C. congregata卵已孵化）；晚期热激组始于宿主5龄第1天（此时绝大多数C. congregata幼虫已蜕皮进入2龄），该时间点介于产卵后8~12天之间。各处理组的样本量为30~60头被寄生的烟草天蛾幼虫（详见补充材料SOM）。 热激处理组的个体需在每日最高温度（daily maximum temperature, DMT）至少2小时前转移至热激箱，并于热激处理最后一天的16:00~17:00移出热激箱。对照组的被寄生宿主在整个发育过程中均保留于标准饲养温度环境中。 温度/时长实验采用2×4因子设计，外加1个对照组，总计9种处理组合。本实验中的所有烟草天蛾幼虫均完成寄生处理。被寄生的烟草天蛾幼虫将接受两种波动式热激温度处理之一：一种每日最高温度为40℃（温度范围30℃±10℃），另一种每日最高温度为42℃（温度范围31℃±11℃）。 两种热激温度处理均采用24小时周期的连续变温模式，每2小时在高低温阈值间完成一次梯度转换。被寄生的烟草天蛾幼虫于产卵当日、每日最高温度出现前至少2小时被置入热激处理环境中。供试昆虫将在热激处理环境中停留1、2、3或4天（即分别经历1~4次每日最高温度热激）。 幼虫将在末次热激当日的16:00~17:00移出热激环境，随后放回25℃±10℃的标准饲养环境中。对照组的被寄生宿主在整个发育过程中均保留于标准饲养温度环境中。 本数据集已完成清洗以剔除绝大多数异常值，但仍需在附带的R脚本中完成部分数据清洗工作。所有日期已转换为儒略日，且生活史相关指标均已计算完成。