Evolution 2014: Aphids protect themselves from parasitoids by harboring a bacteria whose viral parasite is toxic

Andrew Smith of Drexel University spoke about a four-species interaction that could best be described as “my symbiont’s enemy is my parasitoid’s toxic enemy” scenario. Aphids can avoid being parasitized by a parasitoid wasp if they harbor particular bacterial strains. What’s interesting is that the bacteria don’t directly confer resistance to the parasitoid: instead, it is the toxin produced by the bacteriophage (virus) that infects the bacteria that repels the parasitoid wasps. Complex!