A closer look at the spatial architecture of aphid clones

Nearly 25 years ago, Ellstrand & Roose (1987) reviewed what was known at the time of the genetic structure of clonal plant species. What is the relationship between space and clonal fitness, they asked. What is the best way for a clone to grow within its ecological neighbourhood? The pot had been stirred 10 years previously by Janzen (1977), who pointed out how little we know about the population biology of clonal organisms like dandelions and aphids. He wondered whether, like good curries, outward appearances masked common ingredients. Because in no small part of the advent of molecular ecology, we know more about clonal life histories today, particularly in plants (van Dijk 2003; Vallejo-Marin et al. 2010). Surprisingly, studies of the spatial architecture of aphid clones have been comparably rare. In this issue of Molecular Ecology, Vantaux et al. characterize the finescale distribution of the black bean aphid (Aphis fabae) and in so doing, help to fill that gap. They describe a moderate degree of intermingling between aphid clones over a growing season--A. fabae clones are ‘sticky’, but only a bit. By mixing, clones directly compete with each other as well. The results of Vantaux et al. (2011) will help to integrate evolutionary patterns in aphids with the appropriate ecological scales out of which those patterns emerge.