The hornet holds the title of the biggest eusocial wasp. Growing to over 2 inches in length these formidable insects are a marvel to look at. Their appearance is very similar to that of a yellow jacket wasp apart from their gargantuan size. Just like honeybees and bumblebees, the hornet lives in a nest with a social structure and a queen.
Not all bees can kill hornets, European honeybee's stings are unable to puncture the hornets hard outer shell and are completely unequipped to deal with the invaders. Japanese bees have developed a method of defeating hornets by smothering them in large numbers until the hornet in question expires from heat exhaustion, effectively being lightly roasted.
The Asian hornet has been popping up regularly in the media recently. In western countries, the hornet is seen as a huge potential threat to the western honeybee. But what about the bees that have thrived and developed alongside these apparent monsters for millions of years? Let's take a deeper look at how Japanese bees kill hornets.
Just like the bees, hornets live in nests. Varying in size but consistently housing a queen and larvae these act as epicentres for daily activities. Scouts are sent to forage for food sources in the surrounding area. This consists of nectar and any other sugar-rich plant secretions. Hornets will hunt other smaller insects for food like bees, locusts and grasshoppers so they can be fed to the waiting larvae.
When the hornet lands in or close to the hive the bees within view will fan an alarm pheromone through the air alerting the rest of the hive to the threat. The honeybees will continue as if nothing is amiss but the mechanisms of the trap are being slowly wound.
The odour of rich honey is too much for the hornet scout to resist and it will move into the hive to reach the precious resources within. As the hornet enters the hive the bees will hold back goading the hornet closer. As soon as the hornet attacks all of the surrounding bees will pounce. Hundreds of bees will rush the hornet, pouncing and forming a writhing ball around it's body.
As the temperature inside the living ball rises the hornet within will begin to overheat and cook eventually expiring. Honeybees benefit from their ability to withstand temperatures two degrees Celsius higher than the hornet. There are also some bees that use the same process to suffocate the hornet under the sheer mass of bees surrounding it.
Unlike Japanese honeybees, the Western honeybees are ill-equipped to deal with these foreign invaders. Their instinct is to attack any intruders but in contrast to their normal foe, the hornets do not go down. The hornet tough outer shell is too thick to be pierced by the sting of the Western honeybee and what ensues is nothing short of a massacre.
Hornets will normally target and kill individual bees to take back to the nest. These will be fed to the ravenous larvae before developing into mature hornets. However, when several hornets are attacking a hive they can release a chemical signal that will initiate an all-out attack. Bees will no longer be collected and returned to the hive, the focus becomes purely killing.
Hornets will sting honeybees mid-air, sending them plummeting to the floor. On the ground, they use their sharp mandibles to instantly decapitate the much smaller bees. In no particular order, hornets will indiscriminately kill any bees around them, slaughtering any bees that cross their path.
Unfortunately, Asian hornets are present on our shores. The main issue is that hornets actively seek out bees as an abundant source of food but British bees are completely unprepared for the assault to come. DEFRA is currently undertaking precautions to try and avoid the widespread of Asian hornets through the extermination of nests. They may, however, be fighting a losing battle, the Asian hornet has been with us since 2004 and by the looks of it, it's here to stay.