First report of the nematode Leidynema appendiculata from Periplaneta fuliginosa.

The smokybrown cockroach Periplaneta fuliginosa has spread all over the world, and is now one of the most undesired invasive alien pests in Japan. Because cockroaches are generally infected by thelastomatid nematodes, they are being distributed around the world with their parasitic nematodes. Nothing is known about parasitic nematode species in P. fuliginosa differences, or similarity of the parasite's population structures between the different countries of the host cockroaches. Here we investigated the P. fuliginosa invasive to Japan and found that 100% of individuals were infected with one nematode species. According to the morphology and the sequence of the D2/D3 expansion segment of the 28S ribosomal RNA gene, we identified the parasite as Leidynema appendiculata. This nematode reproduced by haplodiploidy and its developmental timing under various conditions is quite divergent. Their population in the hindgut of P. fuliginosa was controlled with a few adult females and a male. This is the first report of the thelastomatid nematode isolated from the smokybrown cockroach, and is the basis for our future research examining the origin, distribution route and immigration history of the cockroach and the impact of L. appendiculata on native Japanese cockroach species.