High-Throughput Assays of Critical Thermal Limits in Insects

Integrating GWAS and Transcriptomics to Identify the Molecular Underpinnings of Thermal Stress Responses in Drosophila melanogaster

“…To assess CT min , we used a vertical jacketed column (modified from Huey et al, 1992) connected to a temperature-controlled fluid bath, and the temperature was monitored inside the column with a type T thermocouple (Supplementary Figure 1A). For detailed assembly instructions for the jacketed column, see Awde et al (2020). For each line, ∼20 males and ∼20 females were combined in the column and submitted to the following thermal program:…”

Validating the automation of different measures of high temperature tolerance of small terrestrial insects

“…We took a two-pronged approach to validate our technique of measuring critical thermal limits: 1) we used species with well-characterized thermal biology, and 2) we directly compare to the manually scored methods across both static and dynamic thermal assays. While, the idea is similar to previous methods suggested for aquatic or terrestrial ectotherms (Burton, Zeis et al 2018, Awde, Fowler et al 2020), we are the first to validate the automated method by comparing UTLs across several treatments using manually scored assays. Furthermore, we verified the generation of activity profiles during heat assays needed for automated analysis on a number of different taxa including rather docile organisms such as woodlice and millipedes (see Fig.…”

“…While we used a commercial tracking software (Ethovision XT, Noldus, Wageningen, The Netherlands), our method does not rely on this particular software (see e.g. Awde, Fowler et al 2020) and can be applied to any software that can generate data on distance per unit time. Third, in addition to the endpoint used (cessation of movement), the collected data contain other potentially interesting information.…”

“…Several earlier studies have used manual scoring of video recordings (Woods and Bonnecaze 2006, Hazell, Pedersen et al 2008, MacLean, Higgins et al 2016, Awde, Fowler et al 2020). However, none of the previous studies validated their assays against manually scored assays.…”

“…Burton, Zeis et al (2018) described a method for automated temperature tolerance of aquatic ectotherms, based on behavioral (movement) tracking of video recordings. Similarly, Awde, Fowler et al (2020) described methods for scoring of cold knock-down (in a knock-down tube) and heat knock-down assays based on semi-automation. While all of the above these are examples of generating phenotypic data that rely less on real time observations, it is not clear how comparable these are to the traditional assays based on real time observations, i.e.…”