It is noteworthy that Drosophila and vertebrate intestinal epithelia are also similar in several respects. These parallels include: the fact that stem cells play an important role in replacing cells that have undergone pathogen-dependent apoptosis; the sequential deployment of Wnt and Hedgehog (Hh) signaling during the differentiation of intestinal epithelial cells (Pitsouli and Perrimon, 2008; Takashima et al., 2008) ; and the formation of the morphologically specialized brush border microvilli and the underlying cytoskeletal terminal web (Li et al., 2007; Morgan et al., 1995; Phillips and Thomas, 2006) .