Defended Hosts are Frassheads

Last week, I told you guys that parasitoid wasps respond to H. defensa, which is a bacterial endosymbiont that protects aphids from wasps.  Next week, I’m going to talk about how H. defensa affects aphid fitness.  But first, what is the magnitude of the protective effect?  Well, it varies with the strain of H. defensa and the aphid species and probably lots of other factors, too.  But in the example that I’m going to discuss next week, aphids without H. defensa have a 38% probability of becoming mummies if they get attacked by wasps, while aphids with H. defensa only have a 4% chance of becoming mummies if they get attacked by wasps (Vorburger et al. 2013).  So, H. defensa reduces the probability of mortality after attack by 89.5%!

 

Stay tuned to see what happens to Sal and Lisa.  Are they up Frass Creek without a paddle?

Reference:

Vorburger, C., P. Ganesanandamoorthy, and M. Kwiatkowski. 2013. Comparing constitutive and induced costs of symbiont conferred resistance to parasitoids in aphids. Ecology and Evolution 3(3):706-13.