Last in our series of discussions on beloved garden insects that perhaps don't belong and may be of dubious benefit is the environmental ambassador the honeybee. Much has been made in recent years about our dependence on honeybees to pollinate food crops. Thirty percent of our food relies on pollinators, and honeybees are by far the most common pollinator used in agriculture.

Native to Europe, Asia, and Africa, honeybees were the first insects to be imported to our country back in the 1600s. Although long established in North America and although feral honeybee colonies are widespread, the honeybee has never become an invasive species.

However, the food crops that depend on pollination such as apples and almonds have increased 300 percent in the last fifty years, and in the process of converting land for agricultural purposes the habitat of ground-dwelling native bees, who also do a fine job of pollinating, is shrinking. Not the honeybees' fault at all, of course. But the ease of which honeybees can be moved from orchard to orchard, from cranberry bog to avocado grove, means that we can ignore the depleting populations of native bees.

There is one sub-species of honeybee that may actually be invasive, the infamous Africanized or "killer" bee. This insect is the result of a 1957 Frankenstein-y science experiment gone awry. A researcher in Brazil was trying to develop a honeybee that would perform in the tropics, a climate the European honeybee can't adapt to. He hybridized the European bee with several strains of other honeybees, including the African honeybee. Although he was careful to keep the hybridized colonies quarantined, one day a substitute assistant let the African hybrids loose, and the resulting generations of Africanized bees have been moving north (and every other direction) since. Their stings are not more toxic than the European honeybee, but they are much more aggressive, sting in mass, and will pursue a perceived threat for up to a mile. In the Southern US Africanized honeybees have interbred with European bees to cause problems (besides being hyperdefensive the AHB can't be easily domesticated for honey production, either.) But all research indicates that this bee can't tolerate the cold, wet, un-African conditions of the north. Philly, we are spared.

As with all insects, "good" or "bad" is a constructed label. Africanized bees, like Asiatic lady beetles and Chinese praying mantids are just doing their jobs. In a world where natural geographical boundaries like oceans and mountain ranges are increasingly irrelevant, we'll have to find peace, however uneasy, with a number of insects we aren't used to dealing with. We may have the home-court advantage, but the insects usually have a bigger team.