TAMSIN MAJERUS: Male killing is caused by bacteria that live in the female ladybird, and they get into her ovaries and, and into the eggs that she produces and somehow, and we don't really know how, they kill off the embryos that are destined to become male. So when she lays her clutch of eggs, normally we expect half of those will end up being female ladybirds, the other half will be male ladybirds; but a female ladybird that has a male killer will often have a clutch of eggs where only about half of them hatch and the whole for hatch go on to become feat. So the males were killed right at the very beginning of their lifetime. it works surprisingly because the female larvae and something, which is slightly disgusting as they emerge from the egg, they need to eat something very quickly or they'll starve to death.They've got male eggs right there that aren't hatching into larvae. They eat those eggs. So they eat their dead brothers, nasty little bit of cannibalism, but -

HZ: Well, it’s pragmatic cannibalism.

TAMSIN MAJERUS: Yeah, exactly.