Buzz off, elephants told

From a FBFriend, a link to Treehugger.com’s story of how beehives are being used to keep African elephants from raiding farmers’ fields. Such a fine story, from a group at Oxford University that happens to include an old mate. ((Lucy E. King, Anna Lawrence, Iain Douglas-Hamilton, & Fritz Vollrath (2009). Beehive fence deters crop-raiding elephants African Journal of Ecology, 47, 131-137.
And hello Fritz, if you’re there.))

Oxford’s press release has the details. In essence, farmers build a fence that consists of beehives strung together on a wire. When elephants brush against the wire the beehives swing and the bees come out swinging. And even thick-skinned elephants are afraid of bees, which sting them around the eyes and — ouch — up the trunk. The result is that “a farm protected by the beehive fence had 86 per cent fewer successful crop raids by elephants and 150 per cent fewer raiding elephants than a control farm without the fence.”

This makes no sense; how can something be 150% lower than something else? Time to check the original paper.

Over the 6-week study period, the two focal farms experienced twenty successful crop raids involving 133 elephants. Farm A, with the beehive fence, experienced seven successful raids involving 38 elephants. Farm B experienced thirteen raids (86% more than Farm A) involving 95 invading elephants (150% more than Farm A; X2 = P < 0.001, df 1) (Fig. 2). In addition, Farmer B recorded a further 71 elephants in eight failed raid attempts that he prevented from entering his farm using his traditional deterrent tactics. In total Farm B had 21 attempted raids by 166 elephants during the 6-week trial, all of which occurred less than 500 m from Farm A. Most notably, by the end of the harvest season, Farm B had almost no crops to harvest, with the farmer estimating that about 90% of his harvest had been destroyed or eaten by elephants, whereas Farmer A was able to harvest relatively successfully collecting a variety of sorghum, beans, potatoes and maize. This suggests that the fence was at least partially successful in deterring elephants.

That’s better, but not much. Almost twice the raids, involving two and a half times more elephants is how I’d put it.

Strangely, the beehives did not need to contain bees to be an effective deterrent. Just the (recorded) sound of angry bees is enough to deflect an elephant who has experienced stings. But if the hives are occupied the farmer gets honey and, presumably, better pollination too.