Host exploitation and fidelity in Acacia gall-invading parasites

Abstract

The form of social organization seen in the Acacia gall-inducing thrips genus, Kladothrips, is credited to the invasion pressures exerted by species of the parasitic thrips genus, Koptothrips. Critical to this conclusion is the assertion that parasite evolution is more or less in lockstep with the divergence of the hosts. Koptothrips populations are thought to specialize in invading specific Kladothrips taxa. I assessed host exploitation patterns of Koptothrips flavicornis and Koptothrips dyskritus within a single host, Kladothrips intermedius. I also investigated, using DNA sequence data, the connectivity of various Koptothrips flavicornis and Koptothrips dyskritus populations. Results from host exploitation investigations suggest that Koptothrips flavicornis and Koptothrips dyskritus exhibit different patterns when invading a common host, while genetic investigations indicate the absence of host fidelity in regions of overlapping host distribution. My study, while narrow in scope, casts some doubt on the existing model for host/parasite coevolution in this system.