It is rare for any species of animal to regularly kill its own in combat.
However, male Dawson’s bees, one of the world’s largest bee species, are so aggressive that they kill each other en masse in a bid to mate with females.
The bees enter a frenzy of fighting, and by the time their deadly combat is over, every male bee is either killed or has perished. The extreme behaviour, which can lead to even females being killed, is caught on film by a BBC natural history crew.
Dawson’s bees (Amegilla dawsoni) are large burrowing bees that nest in the baked soil of the Australian outback. … As a female emerges, the male bees turn on one another, competing intensely to get access to her. Bundles of male bees form, with each trying to bite and sting another to death. The result is mass murder, with whole generations of male bees wiping each other out to mate with females. This frenzy of killing has been filmed by a BBC camera crew producing the landmark natural history series Life.
Usually one male will emerge from the fighting frenzy to carry a female away to be mated. But sometimes the males are so aggressive they they kill the females they are attempting to meet. Another irony is that for most of the year, Dawson’s bees form extremely harmonious communities. That is because once the mating season is passed, all the males have either killed each other or since perished, leaving an all-female community to produce the next generation. …