The evolution of plant-parasitic nematodes (PPN) is unusual in that these organisms have acquired a range of genes from bacteria via horizontal gene transfer (HGT). The proteins encoded by most of these genes are involved in metabolism of various components of the plant cell wall during invasion of the host. Recent genome sequencing projects for PPN have shown that Glycosyl Hydrolase Family 32 (GH32) sequences are present in several PPN species. These sequences are absent from almost all other animals. Here, we show that the GH32 sequences from an economically important cyst nematode species, Globodera pallida are functional invertases, are expressed during feeding and are restricted in expression to the nematode digestive system. These data are consistent with a role in metabolizing host-derived sucrose. In addition, a detailed phylogenetic analysis shows that the GH32 sequences from PPN and those present in some insect species have distinct bacterial origins and do not therefore derive from a gene present in the last common ancestor of ecdysozoan species. HGT has therefore played at least two critical roles in the evolution of PPN, enabling both invasion of the host and feeding on the main translocation carbohydrate of the plant.

A new thelastomatid species, Aoruroides cochinchinensis sp. n., is described from the hindgut of Vietnamese Panesthiinae cockroaches collected in Bi Doup-Nui Ba National Park. It is the first report of nematodes of the genus Aoruroides Travassos & Kloss, 1958 from mainland Asia. Aoruroides cochinchinensis sp. n. males are characterized by thorn-like cuticular projections on the head end, maximal value of de Man index a (19.5) within the genus, and the nerve ring situated on the border of corpus and isthmus. Earlier, only knob-like cervical cuticular projections were described for males of A. queenslandensis Jex, Cribb & Schneider, 2004.

253 SummaryThe egg-shell ultrastructure of Blatticola blattae has been studied under scanning and transmission electron microscopy. Similar to other studied oxyurids, it consists of five layers: a lipid layer, a chitinous layer, a vitelline layer, internal and external uterine layers. Unlike in the closely related thelastomatid Hammerschmidtiella diesingi, the external uterine layer of B. blattae has a honeycomb structure, the complex system of tightly joined prismatic chambers.

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