It boggles my mind to consider how many millions of tonnes of horticultural material must be shipped around the globe each year. And with the plants and soil come the insects.
It boggles my mind to consider how many millions of tonnes of horticultural material must be shipped around the globe each year. And with the plants and soil come the insects. We are lucky in the UK in that we have a relatively cool temperate climate where most tropical species cannot survive, but plenty of aliens have made it here and many more are sure to come.
This was brought home to me recently when I was examining some insect specimens collected last year as part of a project looking at brownfield sites in and around London. One of the sites was the Bluewater shopping centre near Dartford, which has been developed and landscaped. Along the north side of the former chalk quarry there are some superb flowery slopes where chalk downland plants and insects abound. There's an increasing list of scarce and unusual insects turning up there.
On 26 June I was there on a blistering hot day and the whole place was abuzz with wildlife. Two insects stuck in my mind. One was a tiny, but very pretty, picture-winged fly, Acinia corniculata, given Red Data Book 1 status - endangered - because it is known from so few places. I found one on the knapweeds (hardheads) in which the larvae live. The second was a weevil I knocked out of a bush nearby. It was a bit like a vine weevil, Otiorhynchus sulcatus, but smaller, rounder and hairier. It was this I had under the microscope.
It turns out to be Otiorhynchus setosulus, a Sicilian endemic. How on Earth had it come to Bluewater? The only conclusion I can draw is that it arrived with the decorative plantings used around the car parks and ornamental lakes. Although unlikely to become a pest like its 'vine' relative, the beetle is probably well established in Britain. It's known from at least a half-dozen places, usually in or close to gardens.