@dboeren: that'd be hard to do as well, more like a master's, PhD thesis as well, since phylogenetics is the best method for this type of study. you'd have to find multiple species, then multiple representatives of that species. Plus phylogenetic work has already been done regarding neps, we somewhat know which species are more recently derived than others.
as for capturing specific prey items, that has been done as well--albimarginata specializes in eating termites, inermis and jamban specialize in winged prey items, etc etc.