One day my sister was sitting in the sun, drinking tea when she noticed a large black and orange wasp laboriously dragging a rain spider across our little road. She watched as it struggled with its heavy load. Eventually it made it to the other side and onto the grass. This was even more difficult but she persevered…until suddenly a Fiscal shrike swooped down and stole the spider! The wasp scurried around for a good five minutes desperately looking for her lost booty, but alas it was gone.
What was going on here? The female spider-hunting wasp stings spiders paralyzing them. She then drags them back to her secluded nest, sometimes a distance of 10 or 15 meters over rough terrain. Once her nest is stocked she lays a single egg on each spider’s body. This ensures that when the egg hatches the larva has a ready supply of fresh food until it pupates! The size of the spider also determines the sex of the wasp that hatches. Smaller prey gives rise to male wasps, and larger prey to female wasps. In this instance the wasp was a Tachypompilus ignitis wasp and the spider a Palystes spider but there are many different Pompilidae wasps that prey on different types of spiders.
