Reproductive quality of honey bee (Apis mellifera) drones in East Texas

Recent declines in honey bee (Apis mellifera) colonies have led researchers to investigate the biological and environmental factors affecting the reproductive health of honey bee queens and drones. Analysis of sperm quality serves as an effective measure of drone reproductive fitness. This experiment investigated the variability in drone sperm quality within and between apiaries around Brazos County, East Texas. Drones were collected from 3-4 colonies in each of 15 different apiaries. Sperm samples were obtained from all sexually mature individuals by first sacrificing the drone and subsequently manipulating the aedeagus to cause the eversion of seminal fluid. The viability of spermatozoa in the seminal fluid was assessed with a dual-fluorescent stain assay using SYBR-14 and propidium iodide (PI). Stained samples were analyzed using flow cytometry and separated into two groups based on sperm viability (i.e., viable vs. non-viable) using ANOVA and Tukey’s HSD tests. We found significantly different proportions of viable and non-viable spermatozoa across apiaries, demonstrating that some colonies produce sexually mature drones of better quality than others during the reproductive season. Our results serve as a baseline for future studies on factors that affect reproductive quality of honey bees.