Hi there, loving your page!
I am on holiday in Andalucia, southern Spain, and right by our front door there is a colony of what look like harvester ants. No more than fifteen centimetres away there are some holes from which some very tiny red ants emerge, about a quarter of the size of the smallest harvester ants. Are these two separate colonies, or different types of the same ant? They don't look related and they don't appear to cross into each others territory. I would have thought they'd be fighting all the time if they're not related. Why might this be? Are their diets different enough that they aren't in competition? Sorry to bombard you with questions!
Greetings from San Francisco, and thanks for writing! We contacted an expert on taxonomy and ecology of Europe and Macaronesia ant species, Dr. Xavier Espadaler; here is what he had to say:
"It is not an unusual situation for different ant species to have nest entrances rather close. Coexistence is a possibility; fighting is another possibility. But if the two societies are already nesting close to each other, it is likely that they differ in some way, in their daily activity cycles, or in their food habits.
It is possible that the harvesting ants (Messor) are living close to a Pheidole pallidula nest. This last species is all too common in Andalucía. Their nest, with one or a few entrances, is usually surrounded by the tiny remains of the scavenging they do upon any kind of arthropod remains or corpses; they may capture living prey as well, if small enough. The remains look like a dark zone, somewhat semicircular, bordering the nest entrance. If you are able to look at them under a magnifier, you would see shining heads, wing or leg or thorax fragments, that are the non edible parts of their foraging."
Hope this helps,
Xavier Espadaler, Flavia Esteves, & the AntAsk Team