The silencing of these two red flour beetle genes resulted in high mortality and severe defects in wing and elytra development, depending on the developmental stage of treatment. This indicates an essential function for cell physiology, but a ligand has not been identified for these proteins to date. The closest homolog in humans is ABCA3 which is related to phospholipid transfer but also to the modulation of cell susceptibility to chemotherapy of tumors. Thus,Sophocarpine CpABC5 may have a special function in this tissue, in addition to a role in lipid trafficking. The highest transcript level of ABC transporters in the intestinal tissue was detected for Cpabc12 which was classified into the subfamily B. It is also expressed in Malpighian tubules but ten times less. CpABC12 is a full transporter, and possesses most likely homology to human ABCB1, 4, 5 and 11 as well as the D. melanogaster Mdr50. Though ABCB4 acts in humans as a transporter for phospholipids in the liver, it is involved in the zebrafish’s cellular resistance to noxious chemicals. Except for ABCB11, which is a bile salt transporter, all the homologous vertebrate ABCB members can confer multidrug resistance. We hypothesize a function in the translocation of phytochemicals for CpABC12 in the gut of C. populi. Cpabc7 is the second ABCB candidate with Sweroside a high expression level in the gut, albeit not as high as Cpabc12. Moreover, Cpabc7 is 3 times more highly expressed in the Malpighian tubules than in the gut. CpABC7 is most homologous to the human ABCB6 which is reported to be localized in the Golgi apparatus, mitochondria, plasma membranes, vesicular structures, or endolysosomes and lysosomes of cells. ABCB6 is discussed to play a role in the heme metabolism, in the drug and arsenite resistance of cells. All eight ABCC candidates highly expressed in the gut tissue cluster together with human CFTR, SURs, ‘long’ MRPs and ABCC4. This implies a broad substrate spectrum for these insect transporters which, however, cannot be specified further from our phylogenetic analysis. All five ABCG candidates highly expressed in the larval gut tissue cluster together with the human ABCG1 and ABCG4.