Hold on to your head... A female Dawson's burrowing bee emerges very carefully from her burrow.

Credit: Terry Houston, Western Australian Museum

~ Becky Crew

Love or hate Valentine's Day, one thing we all should be grateful for is that fact that the vast majority of human courtships don't involve accidental decapitations.

Of all the courting methods in the animal kingdom, it doesn't get much more extreme than that of the Dawson's burrowing bee from Western Australia. Sure, black widow spiders often make a meal out of their post-coital partners, but at least the males got the chance to spread their genes first.

At up to 2.5 cm in length, the Dawson's burrowing bee (Amegilla dawsoni) is one of the biggest species of bees in the world. The male's thorax is covered in a rich, golden fleece, while the female sports a soft, white coat. Rather than living together in colony like other species such as honeybees, Dawson's burrowing bees are a solitary species - each one lives in its own burrow constructed in the arid clay pans (or dry rivers) of outback Western Australia.

In some areas several thousands of individuals will position their burrows in close proximity to each other, which can spell disaster when the males' highly aggressive streak kicks in at the start of the mating season.

Each year with the passing of the hibernation period, the males will emerge from their burrows, desperate to reproduce. Before the females have a chance to emerge, the larger males will engage in a brutal battle against each other, while the smaller males keep well away, patrolling the periphery of the burrow area.

When a female eventually emerges, her scent drives the larger males into a murderous frenzy, and they will bite and sting each other to death in order to get to her. Sometimes the females can find themselves caught up in the scuffle as multiple males frantically dive-bomb the same potential mate, sometimes accidentally decapitating her. About 90% of all receptive female bees are mated with immediately upon emergence, with the remainders usually picked up by the minor males on the periphery.

There aren't many species in the world that try to eliminate themselves so zealously, and you've got to feel sorry for the females that can barely emerge out of hibernation without the threat of having their heads knocked off by a bunch of males who are supposed to be courting her. But the good news for the females that survive the mating frenzy is that once things have died down, the remaining males will die, leaving a peaceful, all-female population until the next generation of young males emerge from their burrows.

As a nod to Valentine's Day this week, we have a couple of features about 'love' in the animal world, including a hitlist of the most bizarre mating rituals in the world, and an investigation into what it means to be a homosexual penguin, or dolphin, or koala.