To be fair, spiders are generally seen as more dangerous and sinister and, yes, even sexier than ants. You've got black widows and tarantulas and spooky webs and so on. There was the old pulp hero The Spider, "Kiss of the Spider Woman," "Spider Baby," etc. Heck, even Captain Janeway posed as "Arachnia, Queen of the Spider People."
Ants, on the other hand, are not generally seen as sexy or scary. Ants are not employed as Halloween decorations. Wednesday Addams did not have a pet ant. Nobody talks about getting entangled in "a treacherous ant-hill of intrigue." Frodo did not fight a giant ant in Mordor. Ants are conscientious worker drones, not spooky, sexy symbols of danger. Spiders are to ants as cobras are to garter snakes.
(Okay, there was "Them," but that's the exception to the rule!)
Ditto for bats, of course.