For many entomologists, the bee crisis is a wake-up call. By relying on a single species for pollination, US agriculture has put itself in a precarious position, they say. A resilient agricultural system requires diverse pollinators. This speaks to a larger conservation issue. Some evidence indicates a decline in the estimated 4,500 potential alternate pollinators – native species of butterflies, wasps. and other bees. The blame for that sits squarely on human activity – habitat loss, pesticide use, and imported disease – but much of this could be offset by different land-use practices.
Moving away from monoculture, say scientists, and having something always flowering within bee-distance, would help natural pollinators. This would make crops less dependent on trucked-in bees, which have proved to be vulnerable to die-offs.
The stress on honeybees grew as native and wild pollinators diminished and farmers came to rely more on honeybees. We've put "all of our pollination eggs in the honeybee basket," says Mace Vaughan, conservation director of the Xerces Society for Invertebrate Conservation in Portland, Ore. "We need more baskets."
An immune-system disorder?
Meanwhile, beekeepers are seeing hives empty in a matter of weeks, sometimes days. The entire adult bee population vanishes, except for a few juveniles. This makes CCD difficult to study. "You have a crime scene, you know a crime happened here, but you don't really have evidence," says Medhat Nasr, provincial apiculturalist in Alberta, Canada. Eerily, the stored honey in the hive remains untouched. Raiding bees from nearby colonies never materialize, as is common.
Records of suddenly empty hives go back as far as the late 1800s, but never on this scale. Beekeepers dubbed it "autumn collapse," "spring dwindle," or "disappearing disease." But Dennis vanEngelsdorp, the acting Penn State apiarist, calls this manifestation the AIDS of bees. The remaining juvenile bees appear to be rife with disease. To him, "It's clear that there is an immune suppression," he says.
What might suppress a bee's immune system is anyone's guess. But many ascribe to a tipping-point theory: A variety of factors may have accumulated until a single straw finally broke the bee's back.