COMMUNITY ASSEMBLY OVER EVOLUTIONARY AND ECOLOGICAL TIMESCALES: GALLWASPS AS A MODEL SYSTEM

Biological communities often comprise characteristic sets of species found together over large geographic regions. How these communities assemble remains a fundamental question in community ecology. Do these communities assemble in a shared common origin, and then spread in parallel to occupy their final range? Or do species disperse form disparate origins, forming many similar communities independently by a process of species sorting?

This CASE studentship project will explore these alternative general hypotheses using a model system based on an introduced and invasive plant pest (the gallwasp Dryocosmus kurriphilus on chestnut) and associated parasitoid wasp natural enemies. The pest was introduced to southern Europe around 2000, and is now common in Italy and adjacent countries. Since its arrival, it has recruited more than 30 parasitoid enemies, primarily from native gallwasp communities associated with oak trees.

Julja will use population genetic markers (intron sequences, microsatellites and potentially RAD SNP markers) to discriminate between host tracking and species sorting models of community assembly for the most important parasitoids associated with Dryocosmus kuriphilus in Europe. She will embed these recent events within a wider geographic structure of the phylogeography of the same species across the Western Palaearctic, whose populations are likely to have occupied their current ranges over timescales of millions of years, rather than decades.

no-return mar13