Tonight was the monthly beekeepers' meeting. We had a lecture about the small hive beetle, which was interesting but has increased by one the list of things to worry about. It is a pest of honey bees, which is not in the UK, yet, but has spread across America and Australia and is heading in our direction.
It came originally from sub-Saharan Africa, where it is only a minor pest, because their bees are extremely good at clearing intruders out of their hives, and are generally much more fierce than the European honey bee. Left to its own devices it would probably have stayed there, as it can only fly about seven miles at the most, and sub-Saharan Africa is bounded on two sides by ocean and on the third by the Sahara. Thanks to human beings moving so much stuff about the planet, not just bees but food, plants, and plant based products, the small hive beetle has made a break for it, and is established on every continent (except Antarctica). In Europe it is still confined to southern Italy, after a Portuguese outbreak arising directly from the importation of honey bees was spotted quickly and wiped out, but you have a nasty feeling it's only a matter of time.
The beetle is quite a lot smaller than a bee, maybe a bit bigger than a bee's head. It lives and lays its eggs in bee colonies. The grubs are truly revolting, wriggly maggots that eat everything. Honey, pollen, bee larvae. They move throughout the hive, chewing their way through the wax, and defecate as they go. You wouldn't fancy honey that contained beetle larvae frass anyway, but in case you did, their excrement contains a yeast that causes the honey to ferment and break out of its cells. The bees mop up the honey and store it again, which merely spreads the yeast further through the hive.
The larvae have to leave the hive and burrow into the ground to pupate, so there might be some prospect of controlling them during that phase of their lifecycle using parasitic nematodes. The adult beetles tend to congregate together in corners out of the way of the bees, who will harass them, so there is some scope for trapping using corrugated card that you then remove and destroy with the beetles inside, or with liquid traps containing cider vinegar, to which they are extremely partial until the point where they drown. It sounds like putting out half grapefruit skins and beer traps for the slugs, and is probably about as effective. There is no chemical treatment available. Mind you, the varroa experience has shown that finding an insecticide that will target the insect pest without also harming the bees is extremely difficult, and if there were just one then the target would soon develop resistance. And there's the problem of not leaving residues in the honey. Honey containing larval droppings sounds bad enough, but at least they're organic. Pesticide residues, anybody?
The Systems Administrator asked when I got home if I had had a nice time, and I said that it had been very interesting and I'd spoken to people and eaten a chocolate biscuit, which was nice, only it was all rather depressing. This worried the SA, until we'd established that it was the prospect of disgusting wriggly larvae that was depressing, not that anybody had died, at which the SA looked simultaneously amused and relieved. I slightly wish I hadn't seen that video clip of the larvae wriggling, though, as I don't want it coming back into my mind if I wake up at three in the morning. It really was singularly unpleasant. The commercial beekeeper there said that what we should really be worrying about was not the small hive beetle, but the Asian hornet, which is already as close to the UK as France and will eat fifty adult bees an hour and forms vast colonies containing thirty or forty thousand destroying insects. So that's two extra things to worry about.
No comments:
Post a Comment