Abstract. In environments where animals have a high probability of encountering temperatures close to their thermal limits, animals with the capacity to minimize the chances of encountering these temperatures will be advantaged. We investigated the physiological and behavioral mechanisms used by flat rock spiders, Morebilus plagusius, to avoid encountering lethal or sub-lethal temperatures on sandstone outcrops by measuring their critical thermal maximum (CT Max ) in spring and summer and quantifying their retreat rock use. Morebilus plagusius has a high CT Max , which acclimatizes seasonally (spring CT Max : 48.38 6 0.28C; summer CT Max : 49.68 6 0.38C). By measuring the operative temperatures available to spiders underneath rocks in spring and summer and quantifying retreat rock use by adult spiders we found that random use of rocks by spiders would frequently expose them to temperatures above their thermal tolerances, especially in summer. Spiders non-randomly used rocks as diurnal retreats, with rocks with a large area and a rock substratum being positively correlated with M. plagusius occupancy. Rocks large in area provided cooler daytime shelters than exfoliated rocks with smaller area. Morebilus plagusius uses both physiological and behavioral mechanisms for avoiding lethal temperatures, and neither physiological nor behavioral mechanisms alone are enough to mitigate the increased probability of encountering lethal temperatures in summer. Our results highlight the importance of an integrative approach, incorporating behavioral, ecological and physiological mechanisms in accessing how animals avoid lethal temperatures in thermally extreme environments.

Written, invigilated examinations are valued for their reliability, economy and academic integrity. Nevertheless, examinations are problematic. Final, summative examinations can disadvantage students who experience assessment anxiety, and students may not receive useable feedback. An alternative is the two-stage examination, where a traditional examination is followed by a group examination with similar questions. Students gain peer feedback on their examination performance, and can meaningfully apply this feedback. Use of this format in tertiary STEM education in universities has indicated that students prefer the format, although it has been little studied in Australia. Furthermore, its effects on reducing stress and fostering deeper learning are not well understood. The COVID-19 pandemic and switch to online learning has provided us with an opportunity to review our assessment practices and has led to a new willingness to test different examination formats. Here we provide a narrative review of the results of previous studies on two-stage examinations and, based on this and our experience teaching in large-cohort introductory biology courses at an Australian university, we propose a formula for employing them in this context.