Australian digger wasp - a predator of the plague locust

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Denis Crawford / Alamy Stock Photo
Following the swarms of Australian plague locust over the summer of 2010/11 were digger wasps (Sphex sp.) of the family Sphecidae. These large wasps dig perfectly round holes in which they place a paralysed locust. The wasp then lays an egg on or near the locust so the hatching wasp grub has ample food. Sphex wasps are very aggressive in attacking locusts and prefer female locusts as they are much larger than male locusts. Sphex are large wasps about 35 mm in length. When they sting a locust to paralyse it, the locust may involuntarily jump a meter or so into the air with the wasp clinging on. A wasp brings a paralysed locust to the burrow, leaves it on the threshold, goes inside to see if all is well, then comes back out and drags the locust in. If you move the locust a few inches away while the wasp is inside making her inspection, when she comes out of the burrow she puts the locust back at the hole, and then repeats the preparatory procedure of entering the burrow to see that everything is all right. If the locust is moved again while she is inside, once again she will move the locust back to the threshold and re-enter the burrow for a final check.
Location: Pomonal, Victoria, Australia