I heard them before I saw them - an incessant hum, loud enough to make it seem as if our tiny aluminium boat was vibrating. But within a second, they were on us. And not just on us - but in us. In our hair, up our nostrils, trying to crawl inside my ear. We were being attacked by a swarm of killer bees.
Only moments before, we had been peacefully gliding up a tributary of the Rio Nosara in Costa Rica, the near-silent throb of the battery-powered boat drowned out by the calls of birds rising from the mangrove swamp. Eckhard, our guide, had been pointing out a crab-eating buzzard resting on a branch only feet above us. We felt like real explorers - my boyfriend, my six-year-old daughter, and I - yet utterly safe. Only the spot where the alligators sunned, leaving long outlines of their bodies like giants' footprints on the sand, suggested a pleasant soupçon of danger.
We were quite close to the shore, and hardly moving, looking for toads at the water's edge, when I heard the hum. Then the bees descended on us, hundreds of them, smothering our skin until it was all bumpy and black. My boyfriend was the first to be stung. He lashed out instinctively, brushing the bees from his forearm. It was a mistake. "Don't move! Don't move!" screamed Eckhard. A killer bee regards any movement as an act of aggression. The bees retaliated, and my boyfriend was stung again.
Eckhard attempted to steer us away from the swarm. This was truly heroic; he knew that even the gentle sway of his hand on the tiller meant he would be stung. The killers went for his uncovered face as he steered a path through the twisted roots of the mangrove trees. Their stings first broke like little splinters, quickly becoming craters of red. We watched. We were not heroes. If we tried to help him, we would be stung again, too.
Eckhard's hand began to wobble on the tiller. He could barely steer. The stings were beginning to make him feel woozy. We couldn't shake off our attackers; killer bees can pursue intruders up to half a mile. Eckhard's panama hat was a black furry umbrella of bees.
"They're still on me, aren't they," he groaned. "Yes," was all I said, my mouth as tight as a ventriloquist.
Eventually, our feeble boat began to outrun the bees. A few stragglers hung on, determined to punish us for invading their territory. As soon as we were free from the swarm, my boyfriend, bitten but less so than Eckhard, tried to remove the stings around Eckhard's face and neck. My daughter, who had been totally silent even when she was stung, suddenly cried. Her wail echoed along the creek, as animal as any sound from the wild beasts.
Despite their ferocious reputation, killer bees do not often attack. In eight years as a guide in Costa Rica, Eckhard had been attacked only once before. Most victims survive. Estimates of the number of fatalities in South and Central America vary from 20 to more than 1,000. But when the swarms started migrating northwards, they began to make headlines in the world's press.
The bees claimed their first Californian victim on May 20, 1998, a pit bull terrier called Killer. The news led to near panic across the country. Last month a 77-year-old woman in Las Vegas suffered a massive attack.
These bees are monsters of our own making. In 1956, African honeybees - Apis mellifera scutellata - were imported from Tanzania to Brazil, in an attempt to improve the honey production of the imported European bees. African bees were used to hot weather, and produced five times as much honey as the Europeans. A year later, 26 colonies of African bees escaped from a research apiary in Brazil and mated with the Europeans to produce Apis mellifera adansonii. Their progeny began to spread throughout South and Central America.
This new strain was different from its parentage, but not as hoped. The hybrid, soon known as the killer bee, is smaller, more vigorous, swarms more often, and is up to 10 times more likely to sting than the European bee. In technical language, killer bees have an "excessive level of colony defence". It was probably the vibration of our tiny engine that attracted them; they are often provoked by power equipment. In California, there have been two attacks on tree trimmers.
Back on the balcony at Nosara Lodge, my stoic daughter scribbled a sign and stuck it to our bedroom door - "Be Ware of Bees". My boyfriend's arms had ballooned up. Eckhard's eyes were so swollen they were nearly shut, and his ears twice their normal size. He was muttering to himself as if on a powerful drug. I strained to make out he was saying. "It's always the small animals, not the big ones, that get you," he burbled. "Better five sharks than 20 killer bees."
