It was a beautiful day to be out at sea. wind was very slight, but along the KwaZulu-Natal coast north of Richards Bay, the swell of the Mozambique current was running strong. I t was the beginning of the tuna season, but there was no sign of them yet. Nor did we see any birds indicating the presence of my favourite quarry, the Natal snoek. don’t like bottom fishing because even after years of ski-boating, except when I’m trawling, still get very seasick on an anchored or drifting boat and working with messy bait just makes it worse. would only fish over a reef if could catch the fish with lures.
However, while 3km offshore, suddenly spotted a relatively shallow reef on the echo sounder. decided to anchor for a short while and give it a try. No sooner did we have a line in the water, when my stomach twisted, so sat back, took a cold drink and watched the horizon. Suddenly a honeybee landed on my arm. From the way she moved about could see she felt just as miserable as did. knew that scouting bees leave their nests with just enough honey in their stomachs to reach the foraging grounds.
If they fail to locate a food source and run out of fuel, they perish, and out here that was to be the fate of this little guy, who was actually a girl. So gallantly offered her a drop of my sweetened drink, which she eagerly lapped up with her little tongue, buzzed her tiny wings and headed for home. Unable to follow her with my eyes, did it in my mind and thought about the highly organised community from which she comes. knew she was a girl because a colony of honeybees is actually an enormous sisterhood. In fact, almost all the bees in a nest are female, from the queen-mother right down to the last worker.
All the workers are daughters of the queen, who can lay 2 000 eggs a day. In the nest there are a small percentage of males, called drones, which develop from unfertilised eggs that the workers lay. They only have mothers and no fathers and only half the number of chromosomes of the females. The sole function of the drones is to mate with the new virgin queens, a task they find so exhausting it kills them. Those that have not done their job and are still alive by autumn are no longer tolerated by the female workers and stung to death.
Dances for dinner W hile sat daydreaming, my companion hooked a fish, so decided to endure the approaching nausea and linger a bit. Within 10 minutes of leaving me our little bee was back, or so thought. So gave her another drink, but after only 30 seconds she or another bee landed again. And then another … and another. Soon the boat was buzzing with bees and it dawned on me the first one must have gone home and revealed my hospitality and our location to the rest of the colony. How did she do that? Just over 60 years ago, in 1947, the German behaviourist Karl von Frisch discovered that bees have a language.
Not a language in the normal sense, but a sophisticated form of body language. do it by dancing. This is the only form of symbolic communication known to exist among invertebrates. There are three basic dances that bees perform. The first is the simple “tremble dance” indicating to other workers that she needs assistance removing dust and pollen grains from hard-to-reach areas of her body.
The other two dances are about the well-being of the colony rather than that of an individual. When a scout discovers a new nectar source, she returns to the hive and in the complete darkness inside, performs a dance along the vertical surface of a comb to communicate to her sisters exactly where the food is to be found. The first is the “round dance” in which the scout will run around in circles. She starts at a point, completes a circle until she arrives at the starting point, then switches around and repeats it over and over. This dance does not indicate direction and she’ll use it when the source is nearby, not more than 75m.
The second dance is the “waggle” or “wiggle-waggle dance” and it’s much more precise. By dancing in a specific way, a scout can indicate the distance as well as the exact direction to the spot where she discovered the new nectar source, even if it’s several kilometres away. The dance consists of two semicircles bisected by a straight line along which the bee runs, while wagging her abdomen from side to side. The direction of this line in relation to the vertical indicates the direction to the food in relation to the position of the sun. The slower the waggle, the longer the distance. The other bees can’t see her, but special organs analyse the vibrations of her movements. As soon as the scout delivers her message, many foragers leave the nest and fly directly to the food to collect it.
The scout remains in the nest to rest. The system collapses This flawless system worked for millions of years, but depended on the precise accuracy of the information. The scout could only gather it if she remembered the location of her nest and was able to fly straight back to it. LqLately this prerequisite is, however, becoming a huge problem. On a global scale, bees seem to be losing their memory. This first came to light in October 2006, when the massive disappearance of honeybees on an unprecedented scale started to occur in the US.
The phenomenon of bees leaving their hives to scout or forage and simply failing to return was eventually identified as Colony Collapse Disorder (CCD). Every year since it started a third of all hives in the US have been destroyed and it has since spread throughout the developed world. As mentioned in the previous article, the total disappearance of bees in China’s apple-producing provinces lately necessitated hand pollination, which is far more labour-intensive than harvesting the crop. Despite a mad scramble worldwide to find the cause, the disorder is still not well understood.
Together with many governments, affected industries have made huge grants available for research. It seems that something is causing the immune systems of bees to collapse, leaving them vulnerable to devastating attacks by mites and viruses. The world is proliferated with genetically modified plants, 130 million acres (52,6 million hectares) of crops are modified in the US alone. The introduced genes make plants either insecticidal or immune to herbicides.
So, the use of herbicides has skyrocketed and the insecticidal genes turn a large part of bee-food nectar into poison. Widely used new pesticides like Imidaclorprid, used against termites and ants, are designed to do exactly what is happening to the bees. Apart from bait, Imidaclorprid is used on and absorbed by plants, and when social insects ingest it, they lose their memory and can’t get home.With global food shortages becoming a reality, we’ll have to help the bees remember the way home, or we can forget about feeding the world’s people.
Contact Abré J Steyn on 083 235 4822 or e-mail [email protected] or use skype name: abrejsteyn. For more on a potential treatment for Colony Collapse Disorder, see Farming for Tomorrow: Heat treatment saves bees from nosema in this issue. |fw
