Fig. 2.

Recently experienced environmental temperatures alter the thermosensory preferences of environmentally motile S. stercoralis iL3s. A. Left: S. stercoralis iL3s initially cultured at 23°C and then shifted to 15°C for 2 h show a dramatic increase in positive thermotaxis when placed at ∼22°C in a 20–33°C thermal gradient. Right: S. stercoralis iL3s initially cultured at 23°C and then shifted to 37°C for 2 h show a slight decrease in positive thermotaxis when placed at ∼30°C in a 21–33°C thermal gradient. ****p < 0.0001, two-way ANOVA with Tukey's post-test. Graphs depict medians and interquartile ranges. In some cases, error bars are too small to be visible. Figure modified from Bryant et al. (2018) with permission (Bryant et al., 2018). B. Model showing the possible temperature-driven movements of iL3s that have recently experienced cooler environmental temperatures. iL3s primarily display positive thermotaxis, which may direct them toward potential hosts. Ethologically, this scenario may arise in the late evening or early morning, when environmental temperatures are low and hosts are active. iL3s are not drawn to scale. C. Model showing the possible temperature-driven movements of iL3s that have recently experienced warmer environmental temperatures. iL3s engage in both positive and negative thermotaxis, which may direct some iL3s toward hosts and some deeper in the soil, where temperatures are cooler. Ethologically, this scenario may arise in the daytime, when environmental temperatures are highest. iL3s are not drawn to scale.