Thermal tolerance of western corn rootworm: critical thermal limits, knock-down resistance, and chill coma recovery

Authors: Roeder, Karl; Daniels, Jesse

Submitted to: Journal of Thermal Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/13/2022
Publication Date: 9/17/2022
Citation: Roeder, K.A., Daniels, J.D. 2022. Thermal tolerance of western corn rootworm: critical thermal limits, knock-down resistance, and chill coma recovery. Journal of Thermal Biology. 109. Article 103338. https://doi.org/10.1016/j.jtherbio.2022.103338.
DOI: https://doi.org/10.1016/j.jtherbio.2022.103338

Interpretive Summary: Western corn rootworm are an economically important crop pest with estimates of damage and control approximating over $1 billion annually. Despite an abundance of research devoted to studying rootworm biology, key aspects on how they tolerate hot and cold temperatures are still lacking. Here we address this knowledge gap for the first time by measuring multiple thermal traits. On average, rootworm could tolerate temperatures between 2.5°C to 43.0°C with survival decreasing as temperatures approached these lower and upper limits. Combined, our results present the first composite picture of different thermal traits for western corn rootworm, which will be vital for predicting their survival and potential spread under future climate change scenarios.

Technical Abstract: Western corn rootworm, Diabrotica virgifera virgifera, is one of the most economically important crop pests in the world with estimates of damage and control approximating over $1 billion USD annually. Despite an abundance of research devoted to studying rootworm biology in the central Corn Belt of the United States, key aspects on their thermal ecology are still lacking. Here we address this knowledge gap by measuring critical thermal limits, knock-down resistance, and chill coma recovery. In doing so, we also address methodological questions surrounding measurements of thermal tolerance using a variety of dynamic and static thermal assays. The average critical thermal maxima across all trials was 43.0°C, while the average critical thermal minima was 2.5°C. Critical thermal limits were relatively invariant across all treatments except at faster ramping rates. Knock-down resistance decreased with increasing temperature as survival dropped from 100% at 39°C to 0% within 10 minutes at 44°C. Recovery from chill coma increased 1.62 minutes for each hour of exposure at 0°C, while survival decreased by 50% after only 24 hours. Combined, our results present the first composite picture of different thermal traits for western corn rootworm, which will be vital for predicting their survival and potential spread under future climate change scenarios.