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The genetic basis of host plant range in herbivores insect is poorly understood. However, it is a crucial factor when studying the coevolutionary arms race of plants and their insect herbivores. Heliothis subflexa and Heliothis virescens (Lepidoptera: Noctuidae: Heliothinea) are sister species, whose last common ancestor is thought to have been polyphagous. While H. virescens is still a highly polyphagous species, H. subflexa is a specialized species, only eating plants of the Physalis genus. The difference in host plant range makes these sister species and ideal model system to study adaptation to hostplants. I aim to identify molecular and physiological mechanisms that determine host plant range in these two species to shed new light onto the evolution of food plant spectra in insects and thereby on general molecular adaptation mechanisms to understand the determination of host plant range on a genomic level.
I use an array of approaches to answer the following questions:
1) Can H. subflexa still digest a wider array of plant toxins and vice versa can H. virescens cope with the Physalis toxins?.
2) How do expression profile of H. virescens and H. subflexa under standardized conditions compare when fed on the same secondary plant compounds?
3) What gene families and potential specific candidate genes are involved in the host plant adaptation of the two species?

HHF Image
Phylogenetic relationship of Heliothis virescens and Heliothis subflexa, simplified from Cho et al (2008). The most parsimonious approach suggests that polyphagy arose at the root of the Heliothis group within in the Heliothinea, here indicated by an arrow. Polyphagous lines are depicted as black lines and oligophagous as grey lines. Behind each species ‘O’ stands for oligophagous species and ‘P’ stands for polyphagous species.
last updated on 2014-04-03