科学美国人60秒:Pollination Isn't Just for the Bees

The widespread death of honeybees has some farmers fretting: if honeybees disappear, who will pollinate their crops? "Almost any kind of insect you can think of." Margie Mayfield, an ecologist at The University of Queensland in Australia. "Globally speaking flies are probably the second largest group of crop pollinators. In particular a group called hoverflies, or syrphid flies. And these are these large-eyed flies that if you take a hike you sometimes see them hovering in front of your face." 

Along with hoverflies, the army of under-appreciated pollinators includes butterflies, moths, beetles, ants and wasps. Mayfield and her colleagues analyzed more than three dozen studies on pollination, covering 17 crop plants grown on five continents. And they found that these underdog insects accounted for some 40 percent of the flower visits. Some of the crops in their review--especially tropical ones like mangoes and custard apples--did not rely on honeybees at all. Even commodities like canola did fine without bees. The meta-analysis is in the Proceedings of the National Academy of Sciences. [Romina Rader et al, Non-bee insects are important contributors to global crop pollination]

Mayfield says part of the difficulty in gauging the importance of bees starts with the research methods: a third of the studies they initially considered, for example, ignored everything but bees. "You know the European honeybee is obviously from Europe, so there's a lot of focus on the European honeybee there." Another issue, she says, is raising awareness among farmers. "I've encountered farmers in California and in South Africa and in Australia who spray their pesticides largely at night, because that's when the bees have gone back to their hives. And they do that with the idea that we'll spare our pollinators and control our pests. But that very much takes the assumption that only bees are important pollinators." Of course we should still do our best to save honeybees--the celebrity pollinators. But agricultural practices should consider the rest of these tiny farm workers, too.

-- Christopher Intagliata