If you’re into assassin bugs- and really, who isn’t- you should check out this recent paper by Hwang & Weirauch:
The evolution of blood-feeding may thus have occurred once or twice independently among predatory assassin bugs. All prey specialists evolved from generalist ancestors, with multiple evolutionary origins of termite and ant specializations. A bark-associated life style on tree trunks is ancestral for most of the lineages of Higher Reduviidae; living on foliage has evolved at least six times independently. Reduviidae originated in the Middle Jurassic (178 Ma), but significant lineage diversification only began in the Late Cretaceous (97 Ma).
Assassin bugs are fascinating predatory insects found all over the world, and this paper is the first modern effort to synthesize this group’s life history with phylogeny. This sort of big-picture evolutionary research is increasingly common, so if you’re new to biology it’s well worth learning how to interpret studies like these.
source: Hwang WS, Weirauch C (2012) Evolutionary History of Assassin Bugs (Insecta: Hemiptera: Reduviidae): Insights from Divergence Dating and Ancestral State Reconstruction. PLoS ONE 7(9): e45523. doi:10.1371/journal.pone.0045523