Hyperactive and synchronized pre-mating behavior of honey bee drones inside the nest

Abstract

Eusocial insects, such as colonies of ants, wasps, and bees, operate as an integrated collective with tasks allocated among individuals. There is a long tradition of detailed work on the female workers that carry out colony tasks. Males, however, are typically ignored, because they do not perform work, and/or they simply disperse from the natal nest. In the Western honey bee, (Apis mellifera), males (drones) live in the colony throughout their lives, but prior research focuses almost exclusively on their behavior outside of the nest (mating flights), while ignoring their in-nest behavior. To understand the in-nest behavior of drones across their entire lives, we used the BeesBook tracking system to track 192 individually-marked drones at 3 fps for 25 days. We used these trajectories to extract behavioral parameters, including how drones developed, how they moved, and where they spent their time. While drones do spend around 21 hours of their time immobile at the periphery of the nest, as expected, we also found that drones have periods of in-nest hyperactivity, in these times moving faster than even workers. This hyperactivity develops in drones after 7 days, occurs daily between 14:00 and 17:00, and is synchronized across the cohort. While active, drones move towards the nest entrance, and gaps in tag detections indicate trips outside of the nest (presumably flying to mating sites). Surprisingly, we even found this behavior on days of poor weather, when drones would not fly, suggesting that drones must inspect the daily weather themselves. While drones are typically attributed to being the lazy members of the colony, here we show that they have hyperactive bouts that surpass even worker activity. The duration, however, is short, likely to conserve energy. Drones are part of the colony’s organization, even if their role is simply to become active once daily to maximize opportunities for mating success.