Nine Toll-related receptor genes are known from the Drosophila genome and 10 from Anopheles (Tauszig et al., 2000; Christophides et al., 2004) . In Drosophila, Toll is the primary family member implicated in immune-related function (Lemaitre et al., 1996) , although it appears that Drosophila Toll-5 and Toll-9 (the paralogue that is structurally most similar to mammalian TLRs), are also involved in immune-related signalling (Ooi et al., 2002; Bilak et al., 2003) . We have identified only five Toll-related genes in the honey bee: Toll1, Toll2/18w, Toll6, Toll8/Trex/Tollo and Toll10.