The wasps that tamed viruses
If you puncture the ovary of a wasp called Microplitis demolitor, viruses squirt out in vast quantities, shimmering like iridescent blue toothpaste. βItβs very beautiful, and just amazing that thereβs so much virus made in there,β says Gaelen Burke, an entomologist at the University of Georgia.
M. demolitorβ is a parasite that lays its eggs in caterpillars, and the particles in its ovaries are βdomesticatedβ viruses that have been tuned to persist harmlessly in wasps and serve their purposes. The virus particles are injected into the caterpillar through the waspβs stinger, along with the waspβs own eggs. The viruses then dump their contents into the caterpillarβs cells, delivering genes that are unlike those in a normal virus. Those genes suppress the caterpillarβs immune system and control its development, turning it into a harmless nursery for the waspβs young.
The insect world is full of species of parasitic wasps that spend their infancy eating other insects alive. And for reasons that scientists donβt fully understand, they have repeatedly adopted and tamed wild, disease-causing viruses and turned them into biological weapons. Half a dozen examples already are described, and new research hints at many more.