Figure 1.

Overview of phylogenetic relationships of Plakobranchoidea (Sacoglossa). Blue rectangles indicate photosynthetic activity over at least two weeks of starvation (based on pulse–amplitude–modulation (PAM) measurements), whereas grey squares indicate species that immediately digest plastids. Slugs showing photosynthetic activities over two months are highlighted in green and the respective pictures of the species and food alga are provided on the right. Photo of E. chlorotica with permission of M. Rumpho, and that of Vaucheria litorea with permission of C. F. Carter. Phylogeny based on Wägele et al. [8].