Fig. 3

Median and distribution of mean hypopharyngeal gland (HPG) acinus size (µm) of workers that prematurely exited the hive as well as their age-matched and forager control counterparts. For all three panels, HPG acinus size is shown in orange for age-matched control bees, magenta for forager-aged control bees, and teal for prematurely exiting bees. Kruskal–Wallis tests were run to detect overall differences between means and Dunn’s tests were run for pairwise comparisons. A Mean HPG acinus size of bees in the cold stress treatment group (26 °C for 24 h) was significantly lower for prematurely exiting bees compared to their age-matched counterparts (p < 0.0001), but similarly sized compared to the forager controls (p = 0.588). B Mean acinus size for bees in the heat stress treatment group (39 °C for 24 h) was significantly lower for prematurely exiting bees compared to their age-matched counterparts (p < 0.00001), but similarly sized compared to the forager controls (p = 0.576). C Mean acinus size for bees in the Varroa mite parasitization group was significantly lower for prematurely exiting bees compared to their age-matched counterparts (p < 0.00001), but similarly sized compared to the forager controls (p = 0.135). Asterisks (“***”) above brackets represent statistically significant differences between groups (at p < 0.001), and “n.s.” indicates no significant differences between groups. Sample sizes: A age-matched control: 50, forager control: 25, premature exit: 25; B age-matched control: 29, forager control: 12, premature exit: 22; C age-matched control: 57, forager control: 21, premature exit: 61