The time of day matters when it comes to yellowjackets’ attacks on honey bees and lavender essential oil can deter wasps from hives

Vespula germanica wasps are natural predators of Apis mellifera bees and can also be problematic for beekeeping. We evaluated the variation in agonistic interactions between V. germanica and A. mellifera hives at two times of the day: noon, when bees exhibited activity at the hive entrance, and early in the morning, when they were not active. Aggressive interactions were 13 times higher during the morning when bees were less active. The most frequent interaction at noon involved wasps approaching the hive, while in the morning, it was frequent to observe wasps entering the hive. We also analyzed the effectiveness of lavender oil as a repellent and found it reduced aggressive interactions by approximately 75% immediately after application, with the effect lasting 48 h. The reapplication of lavender oil at the hive entrance extended its effect for 24 h. We concluded that bee activity, measured as bee traffic at the hive entrance, could be an indicator of susceptibility to wasp attacks and a key factor in this predator‒prey interaction, making hives more susceptible to V. germanica attacks in the morning. Similarly, lavender oil acts as a repellent agent, reducing the impact of wasps in the short term.