Host Plant Specialization Governed by Facultative Symbiont

Abstract

In North America and Europe, the pea aphid ( Acyrthosiphon pisum ) encompasses ecologically and genetically distinct host races, offering a model system for studies on sympatric speciation ([ 1 ][1], [ 2 ][2]). One host race lives on red clover ( Trifolium pratense ) and cannot produce offspring on