von tail__ » 15. Mär 2008 08:52
1. The best are all Formica species, which generally tend to accept each other's pupae and larvae (i don't know if eggs too, but probably not). Others usually accept only brood of their own species, and sometimes of the same subgenus. Parasite and host species also accept each other's brood, e.g. Lasius umbratus and L. fuliginosus. Making joint Lasius/Camponotus colony is absolutely impossible.
2. Sometimes it's possible, but probably only in the same subgenus - so not with Lasius (Cautolasius) flavus and Lasius (Lasius s.str.) niger, but maybe with L. niger and L. emarginatus. This is unlikely, however, these ants lived together for millions years and they are sexually unattractive to each other (different sexy scent tastes). Sometimes hybrids are effect of introducing alien species, which never lived together, for example Solenopsis invicta and S. richteri, both introduced to USA, do make hybrids.