Stunning but ruthless
This colourful wasp lays its eggs in several different hosts, at their peril.
The breathtaking beauty of the crypt-keeper wasp (Euderus set) belies its parasitic tendencies to lay eggs in at least seven different wasp species.
It lays its eggs inside a small chamber that the gall wasp creates in live oak trees. When the crypt-keeper’s egg hatches, the larva somehow forces the other wasp to chew a small exit hole in the side of its larval chamber in a bid for freedom.
The hole is too small for the gall wasp to escape from, however, and it gets stuck. Our protagonist then feeds on the wasp’s disabled body and, once fully grown, escapes from the gall by chewing through its host’s head that’s plugging the hole.
Anna Ward and co-authors now report in the journal Biology Letters that the delightful insect attacks and alters the behaviour of at least six other wasp species across five genera, which is unusual as parasites normally have a limited host range.
The gall wasps are taxonomically diverse but form similar structures. The authors suggest therefore that the crypt-keeper’s host range is influenced by its hosts’ similar phenotypes, rendering them physically defenceless for instance, rather than its ability to manipulate its victims’ behaviour.