We are using the wealth of data in the Psyl'list database to analyse patterns of psyllid-host plant evolution.
Each species of psyllid, or jumping plant louse, feeds on a particular type of plant. Sometimes, a psyllid species feeds only on one species of plant, but more often it is limited to one genus of plant.
When plants diversify, psyllids are good at adapting to those changes: they are highly effective at tracking diversification within particular host plant groups. However, psyllids do not seem to be undergoing cospeciation with their hosts.
Using the Psyl'list database, we will analyse patterns of global psyllid-host plant associations. We can then see whether smaller patterns in particular psyllid lineages or biogeographic regions can be extrapolated across the Psylloidea.
The Psyl'list database is worldwide in scale and contains virtually all of the published host-plant associations. We are analysing this data using two methods:
When there is a close association between two species, they may branch into new species at the same time.
This is common for hosts and their parasites. As the hosts come into less contact and begin to become two different species, so the parasites also have less contact and can speciate alongside the host.