Honey guides, killer bees and land mines

The story of the honey guide and the honey badger (aka the ratel) is an interesting one, but is it true? It is frequently reported in text books but there appears to be little evidence that the birds actually guide the ratels to the bees nests. Birds are certainly found when ratels tear into the nests but that doesn't indicate they helped the ratel get there.

There is no doubt, however, that the honey guides can lead people to birds nests and their behavior has become quite sophisticated. The Boran people of northern Kenya are able to summon the birds to their camp before a bee hunting expedition by giving a particular whistle. So honey guides do have a mutualistic association - but with humans rather than ratels. Whether this evolved from a prior relationship they had with the ratel is currently unknown.

When I mentioned this today I suddenly wondered whether it would be possible to use honey guides to detect Africanized bee nests (aka killer bees). When killer bees first invade a new area there is a considerable economic cost as farmers and other outdoor workers need to be more careful. Like land mines, much of the economic cost comes about as the cost of farming increases and people are denied access to certain areas. Fortunately this probably isn't necessary. Most human incidents with Africanized bees occur within a couple of years of the bees' arrival and then subside as the bees interbreed with local bees - especially if beekeepers cull the queens of the most aggressive strains.

Curiously, the aggression of Africanized bees may be due to the ratel. The colony most likely to survive a ratel attack was the fiercest one and so natural selection strongly favored fierce bees. European bees did not have to contend with anything quite as vicious as the ratel.

On the subject of land mines it is interesting to note the number of biological alternatives that are now becoming available for demining areas (a need that is sadly increasing - mines are still being laid 25 times faster than they are being cleared). Since it costs one to two million dollars to clear a single square kilometer of land there are obvious benefits to any cheaper, more accurate and safer method than demining by hand. Hitting news headlines within the last few years have been the Gambian pouched rat, which can sniff out mines, and the humble Arabidopsis (or cress) which has been manipulated to create a strain that changes color to red in response to the nitrous oxide that leaks from landmines and other explosives. The picture at the top of this post shows the quite dramatic color difference.

In a strange coincidence, the oddly shaped South African Infantry Fighting Vehicle is called the Ratel, after the animal - which has a reputation as a ferocious fighter. It's an odd shape because the bottom of the hull is angled in a v shape to deflect mine blasts.