All Hallow’s Eve will soon be upon us, so Extraordinary Animals will be looking at creatures with even more macabre and sinister behaviours than usual. We’ll be starting off proceedings with this insect, the sexton beetle.
Even if we disregard the beetle’s rather ghoulish alternate names – the burying beetle, the grave-robber beetle, the carrion beetle and so on – or even its classic orange and black Halloween colours, this insect still exhibits some morbid behaviour, especially when it comes to breeding and raising its young. Here’s how a parenting guide for burying beetles might look…
Step 1: Find a suitable corpse
Firstly, the burying beetle detects the smell of a small dead animal, perhaps a little bird or a mouse, and heads towards it. If a male discovers a corpse and there is already a female there, the two will promptly consummate their new relationship; if not, he will release a sex pheromone to attract a partner. If there are other beetles there, or they come along later on, they will fight amongst themselves (males vs. male, females vs. females) to gain control over the carcass until one pair emerges victorious.
Step 2: Hide the corpse
After working so hard to claim the animal corpse, the last thing the burying beetles want is for another animal to come along and eat it or take it away. So the beetles, living up to their name, start to bury it. They create a pit around and beneath the corpse so that it falls into this underground crypt, effectively obscuring it from view. They also coat the corpse in antibacterial and antifungal secretions (from their anuses, no less) to slow down the decaying process. Both male and female will spend some time removing feathers and fur from the corpse until it looks like a compact, featureless, de-boned lump of flesh.
Step 3: Feed the babies
The female lays her eggs on the carcass so that when they hatch a few days later, the emerging larvae can feed on its flesh. In many species, the larvae cannot tear off chunks themselves, so they rely on their parents to provide them with food. The adults partially digest the flesh first and then regurgitate it for their offspring. The young maggots may even rear up and beg for food like baby birds. After voraciously feeding on the carcass for several days, the beetle larvae will burrow into the soil and pupate, ready to emerge the next season as adults.
Step 4: Cull the babies (Optional)
The parents aren’t always so blissfully nurturing. One day, as the larvae continue begging for food, the female may suddenly grab and eat one of them. Has she finally snapped? Not quite. When the female originally laid her eggs, she could have no idea how much of the animal carcass would be lost to scavengers or even micro-organisms, but she nonetheless optimistically laid a large clutch. If food becomes scarce later on, she must cull her offspring until the balance is right to prevent all of them from being underfed. All to do with the greater good and all that.