Data from: Prolonged Diapause in Mormon Crickets: Embryonic Responses to Three Measures of Time

Mormon cricket eggs can remain diapausing in soil for multiple years without forming an embryo. I investigated whether embryonic development was dependent on the number of annual cycles since the egg was laid, duration of the summer period (forcing), or duration of the winter period (chilling). This was a lab experiment conducted at the ARS Northern Plains Agricultural Laboratory in Sidney Montana on two populations: Arizona (AZ, 36.5018 N, 112.1405 W, 2592 m above sea level) and Wyoming (WY, 44.4644 N, 107.4592 W, 2653 m a.s.l). The timing of Mormon cricket egg development was measured for each sibling group (designated mating pairs in the header row) within a population. Hence eggs within sibling groups are considered independent observations, and each sibling group was ultimately analyzed separately. Each sibling group was split into three treatments: 2cycle, 3cycle, and 4cycle (designated 2, 3, and 4 in the data), named for the number of seasonal cycles completed within a 60 week period. Two-cycle is best described as 15 weeks of winter, 3 weeks of spring, 10 weeks of summer, and 2 weeks of autumn; three-cycle is 6 weeks of winter, 2 weeks of spring, 10 weeks of summer, and 2 weeks of autumn; and four-cycle is 6 weeks of winter, 2 weeks of spring, and 5 weeks of summer, and 2 weeks of autumn. For 2cycle and 3cycle, eggs were screened for development in the final two weeks of each cycle (the autumn period), and the developed eggs were separated from the undeveloped eggs. Half-developed eggs (or ‘middies’) were also separated from the undeveloped eggs to follow the completion of their development separately. Initially, eggs in 4cycle were also screened in each ‘autumn’ period, but the embryos were unable to complete development in a single screening. Therefore, we were able to screen 4cycle every other autumn period. For each egg in the sibling group, we tracked the timing of the fate of each egg: either fully developed (and thus ready to enter winter and hatch the following spring), discard (due to being flat, black, or invaded by fungus), broken, mia (or missing in action when accidentally lost), or right censored (for the few eggs in a sibling group that still remained undeveloped at the end of the experiment). Any middies that were found hatched were assumed to have completed development in the prior summer. For some mating pairs, we also collected a few eggs and fixed them, which killed the eggs, but cleared the chorion so that we could review their developmental stages (fate=fixed). The treatments were applied for approximately 10 calendar years starting in 2013 when the eggs were collected and ending in 2023. The timing of the fate of each egg was calculated in three ways: 1) the number of warm periods that the egg had experienced (designated ‘wp’ in the header row), the number of weeks of chill time that the egg had experienced prior to its fate (designated ‘winter chill’), and the number of weeks of warm period that the egg had experienced when its fate was determined (designated ‘summer weeks’ although it also includes the 2 weeks of autumn).

摩门蟋蟀的卵可以在土壤中进入休眠状态多年而不形成胚胎。本研究旨在探究胚胎发育是否依赖于自卵产出以来的年度周期次数、夏季期间（诱导）的持续时间，或冬季期间（冷却）的持续时间。该实验在位于蒙大拿州西德的美国农业研究服务局北部平原农业实验室进行，研究对象为两个种群：亚利桑那州（AZ，北纬36.5018，西经112.1405，海拔2592米）和怀俄明州（WY，北纬44.4644，西经107.4592，海拔2653米）。对每个种群中每个同胞组（标题行中指定的交配对）的摩门蟋蟀卵发育时间进行了测量。因此，同胞组内的卵被视为独立的观测值，每个同胞组最终均单独进行分析。每个同胞组被分为三个处理组：2周期、3周期和4周期（数据中分别标记为2、3和4），其命名基于在60周期间完成的季节周期数。2周期可描述为15周的冬季、3周的春季、10周的夏季和2周的秋季；3周期为6周的冬季、2周的春季、10周的夏季和2周的秋季；4周期为6周的冬季、2周的春季、5周的夏季和2周的秋季。对于2周期和3周期，在每个周期的最后两周（秋季）对卵进行发育筛选，并将发育的卵与未发育的卵分离。半发育的卵（或称‘中途发育卵’）也从中分离出来，以单独追踪其发育完成。最初，4周期的卵也在每个‘秋季’期间进行筛选，但由于胚胎无法在单次筛选中完成发育，因此我们只能每隔一个秋季进行4周期的筛选。对于同胞组中的每个卵，我们追踪了每个卵的命运时间：完全发育（因此准备好进入冬季并在次年春天孵化）、废弃（由于扁平、变黑或被真菌侵入）、破碎、失踪（或因意外丢失而无法找到）或右截断（对于同胞组中少数仍未发育至实验结束的卵）。任何发现的已孵化中途发育卵均假定已在先前夏季完成发育。对于某些交配对，我们还收集了一些卵并对其进行固定，以杀死卵并清除卵壳，以便我们能够检查其发育阶段（命运=固定）。处理从2013年开始，当年收集卵，至2023年结束，大约持续了10个日历年。每个卵的命运时间以三种方式计算：1）卵经历的温暖期次数（标题行中标记为‘wp’），在卵的命运之前经历的冷却周数（标记为‘冬季冷却’），以及当确定卵的命运时卵经历的温暖周数（尽管它也包括了2周的秋季，标记为‘夏季周数’）。