Un-nesting DNA Russian dolls
A molecular protocol has been developed in order to identify parasitoid species attacking aphids, and hyperparasitoids attacking parasitoids. The novelty of this method is that species identification relies on DNA left behind by parasitic organisms after their emergence from the aphid they have killed. In practical terms, this allows to reconstruct food webs up to five trophic levels by using easily-collectable aphid ‘mummies’.
This method has been tested with cultured aphid mummies and published in Molecular Ecology (Varennes et al., 2014). Based on this approach, an international collaboration has been set up (EU-funded APHIWEB project) to construct and compare aphid-based food webs in different globally distributed locations, and better understand how food-web biogeography can explain ecosystem functioning.