how was the africanized honey bee spread to america and how has it caused problems with native species?

Answer 1

African honeybees are hardier than the familiar "Italian" honeybee, so an effort was made a couple decades back to see if African bees could make acceptable "tame" beekeeping bees. Some of the bees, as you might have been able to predict from watching countless movies, escaped and hybridized happily with less aggressive honeybee strains. Unfortunately, the hybrids got every last ounce of the African stock's fierce aggressiveness, which kind of creates a problem for beekeepers (and anybody else who comes near the hives). Like Fire Ants and us Europeans, they've since been expanding their range in the New World with enthusiasm, much to the annoyance of the previous inhabitants. Just like with Fire Ants and us Europeans, though, it doesn't look like the previous inhabitants are going to be able to do much about it except hope to hang in there and learn to live with it.