My last "More Urban Species" post begs a bit of illumination.
The pseudoscorpion, looking as it does like a tropical or desert animal, seems an unlikely candidate for New England residence. And it might be, were it not for the constant temperate to tropical conditions found inside buildings in our region. Indeed, warm enclosed spaces, heated and humidity controlled to human preferences, provide habitat for a long list of animals that would perish in the unforgiving cold of say, today, outdoors in Boston. It is only because the pseudoscorpion (being so small and secretive) is less often seen that the others are accepted as normal.
The great indoors of North America and in fact everywhere else, harbors a vast array of creatures that originally came from elsewhere, because the conditions inside are close enough to the conditions out of doors in their native ranges. Add to that the veritable feast of waste, and of prey grazing on that waste, and the list of creatures from the Mediterranean, Subtropics, and Tropics becomes quite impressive. International trade of objects, plants, and foodstuffs guarantees a broad distribution of this fauna. Areas just around buildings comprise another kind of habitat, and I've included a few outdoor urban species from the warm Old World too.
Here's a truncated list, based on what little I know; please correct me if you know I am mistaken (entomologists, I'm hinting in your direction). Note how often the word "house" modifies the common name.
House Pseudoscorpion Chelifer cancroides Probably from the Mediterranean.
Indian Meal Moth Plodia interpunctella Tempting to say India, but they could be from anywhere warm where grain is stored.
Sawtooth Grain Beetle Oryzaephilus surinamensis The Scientific name suggests Indonesia, but that just means they were in Indonesia (in rice) by the 18th century, when Linnaeus described them. Once again, could be from anywhere warm where grain is stored.
Little House Fly Fannia canicularis Old World tropics. Probably spread alongside poultry agriculture.
House Sparrow Passer domesticus Mediterranean. Followed agriculture to Northern Europe. Helped along across oceans by deliberate human action.
House Mouse Mus musculus. Central Asia? The Middle East? Someplace with lots of caves and not much water.
Garden centipede Lithobius forficatus Probably the Mediterranean.
House centipede Scutigera coleoptrata. The Mediterranean.
Pill Bug Armadillidium vulgare. The Mediterranean.
Silverfish Lepisma saccharina. Probably the Mediterranean.
American Cockroach Periplaneta americana. Tropical Africa. As far as I know, all of the pest cockroach species are native to the Old World Tropics.
House Fly Musca domestica. Probably tropical Africa. I suspect the same is true of the stable fly, although the literature surrounding these two very similar looking species is confused. If someone knows for sure, I'd love to find out.
Almost forgot these deliberate introductions:
European starling Sturnus vulagaris. From the Mediterranean, but cold doesn't seem to stop their progress in world domination.
Rock pigeon Columba livia. From the Mediterranean. The wild type isn't doing so well, but the feral/semi-domestic/urban type continues to be ubiquitous.
Honey Bee. Apis mellifera. From the Middle East or India. Domesicated long enough for distinct regional varieties to be developed (Including "Africanized" bees from, you know, Brazil). These insects are important enough for commercial agriculture that people mistakenly believe that their disappearance has something to do with nature.
And don't forget:
Norway rats are from Asia some place, and Black Rats are from coastal, tropical Asia.
Most urban slugs are from the Old World, but I haven't figured out which if any are Mediterranean or Tropical. Probably the greenhouse slug is. Likewise I didn't include urban soil fauna that's European in origin, but may be temperate species from northern Europe, like the European ground beetle, the European earwig, the devil's coach horse, and the shiny woodlouse.