Why hasn’t SHB spread further in Italy?
Small Hive Beetle (SHB), which appeared in Italy in 2014 and in the same area again this year, poses a serious threat to beekeeping, but it seems not to have spread very far in Italy yet. Action by the Italian authorities and a fortunate quirk of the local topgraphy seem to be helping to contain it.
In September we reported on the reappearance of SHB in southern Italy. It was a great disappointment, but there has been relief that it doesn’t yet appear to have spread from the area in which it was originally discovered.
At the Hampshire Beekeepers Autumn Convention last weekend, Nigel Semmence, of the UK Plant and Animal Health Agency, has responsibilities to try to keep out non-native species and revealed why the spread hasn’t happened as well as a very curious characteristic of SHB.
Fortunately, SHB’s first appearance was in a valley surrounded by mountains and the sea in Calabria, Southern Italy. No-one yet knows how or when it arrived, but the mountains may well have provided a barrier to its spread. In addition, the Italian authorities imposed a surveillance zone (even larger than required by regulations). The appearance of SHB on Sicily seems to have been a result of colony movement by a Calabrian beekeeper before the beetle was discovered.
Nigel also revealed some quirky habits of SHB. When attacked by bees, they close their legs and therefore find it difficult to move. At which point, the bees often encase them in propolis. But SHB can generate signals that persuade the bees to feed them! So the bees often leave a little hole in the propolis tomb through which they can feed their enemy! Ah, the wonders of nature!
There is an excellent SHB leaflet from the Animal and Plant Health Agency (not yet online, I think).
If SHB does arrive in Britain, plans are afoot (including the use of nematodes) to try to prevent its spread. There are sentinel apiaries throughout the country at possible entry points.