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Although most of the insect herbivores under study in our institute feed by chewing on plant material, herbivores that suck plant fluids, such as aphids, whiteflies, thrips and leafhoppers, are a prominent group that causes enormous damage to natural and cultivated plants worldwide. We are investigating the pea aphid (Acyrthosiphon pisum), a model sucking herbivore whose genome has been fully sequenced, to understand the causes of feeding specialization on different host plants. Collectively, pea aphids feed on a range of host plants in the Legume family (Fabaceae), but host races exist that exhibit a clear preference for specific plants such alfalfa (Medicago sativa), red clover (Trifolium pratense), pea (Pisum sativum), upon which they perform better. This ecological specialization can be considered a first step towards sympatric speciation since the host fidelity of races leads to assortative mating which reduces gene flow among host races.

The specialization of pea aphids is thought to arise principally from their diet. Although phloem generally contains a high concentrations of sugars and free amino acids, as well as some macromolecules such as proteins or RNAs, a large range of secondary metabolites accumulate whose content varies with the plant species. Some legume secondary metabolites, for example saponins in alfalfa, and alkaloids in white lupine (Lupinus albus L.) have a strong influence on pea aphid performance. However, the role of host plant chemistry for the specificity of pea aphid host races has not been studied.

The aim of this project is to understand the chemistry that mediates the interactions between pea aphid host races and their host plants alfalfa (Medicago sativa), red clover (Trifolium pratense), pea (Pisum sativum) and broad bean (Vicia Faba) using LC-MS and GC‐MS based metabolomic approaches.
last updated on 2017-01-24