Title: Buff-tailed Bumblebees Prove Their Wrestling Skills Against Invasive Asian Hornets
Subtitle: Researchers surprised by the bumblebees’ successful defense strategy, but dismayed by the ecological impact
by [Author Name]
[Date]
In a surprising turn of events, scientists from the University of Exeter have discovered that the buff-tailed bumblebee possesses a remarkable defense strategy against invasive Asian hornets. The researchers were astonished to witness the bumblebees successfully fend off hornet attacks by using a wrestling-like technique.
Asian hornets have become a global menace, having invaded multiple continents and reached record sightings across the UK and continental Europe in 2023. These predatory insects pose a significant threat to ecosystems as they prey on various insects, including crucial pollinators like bees, disrupting the delicate balance of the natural world.
Thomas O’Shea-Wheller, one of the authors of the study, highlighted the problems caused by Asian hornets: “Hornets also consume nectar from flowers, meaning they compete directly with bees for food and harass them at flower patches via constant attacks.” Unfortunately, nature does not provide bees with insect restraining orders.
Amidst these challenges, the study revealed that the buff-tailed bumblebees, known for being among the most common social species in Europe, exhibited an unexpected ability to defend their colonies against Asian hornets. The researchers conducted their experiment in Pontevedra, Spain, placing commercially reared buff-tailed bumblebee colonies at various locations with different densities of Asian hornets.
To capture the interactions between the two species, the scientists utilized automated camera monitoring systems, which recorded over 120 hornet attacks. Remarkably, they observed that the bumblebees successfully repelled the hornets on every occasion using a novel method. When attacked while returning from foraging, the bumblebees dropped to the ground abruptly, causing the hornets to lose their grip or both insects to tumble. This unexpected tactic provided the bumblebees with an opportunity to engage in a wrestling-like struggle until the hornet gave up and retreated.
The researchers described this defense strategy as an “evolutionary coincidence” since the buff-tailed bumblebees and Asian hornets did not co-evolve. Consequently, the bumblebees theoretically should not possess a natural resistance to the hornets. Their success in fending off these invasive predators, therefore, left the scientists astounded.
However, despite their impressive defensive capabilities, the buff-tailed bumblebees ultimately succumb to the ecological impact of the Asian hornets. The researchers found that bumblebee colonies living in areas with higher densities of Asian hornets exhibited slower growth. The reasons for this phenomenon remain uncertain, but it is likely that the presence of the hornets limits the success of the bumblebee colonies.
O’Shea-Wheller explained the possible consequences: “Defending against such attacks is likely energetically costly—and when hornet abundance is high, this could be a major problem for bees out foraging.” While the hornets’ attacks at the colonies’ entrances were frequently unsuccessful, Asian hornets have been reported to prey on bumblebees elsewhere, indicating a significant threat to their population.
The study highlights both the resourcefulness of the buff-tailed bumblebees’ defense mechanism and the ongoing challenges faced by pollinators like bees due to the presence of invasive predators. Despite their valiant efforts, the bumblebees’ victories against Asian hornets come at a cost, with the hornets’ abundance potentially limiting the prosperity of the colonies.
As researchers continue to explore the complex interactions between species and the impact of invasive predators, it is crucial to develop sustainable strategies to protect and conserve essential pollinators, such as the buff-tailed bumblebees.
The study documenting these fascinating findings was published in Communications Biology.
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