It might sound more like something out of a horror B-movie than real life, but in November last year a single Black Widow spider who experts believe had hitched a ride from Texas spawned more than 100 offspring, in what is thought to be the first ever infestation of the deadly spider in Britain.
Here in the UK we are unused to having to worry about exotic and venomous pests, however with global warming increasing average temperatures worldwide, can we expect to see a day when insects more commonly found in warmer parts of the world start finding their way to these shores?
Longer Seasons & Native Pests
Before even considering the impact of global warming in relation to foreign insects coming to the UK, it is important to note that our own native pests are surviving longer as climate change affects our seasons.
Pest control companies are finding that insects which would typically cause problems between May and August – such as wasps and cluster flies – are making appearances earlier and surviving for longer as the winters and autumns turn more mild. Back in the autumn of 2011 – the warmest since 1659 – unnaturally high temperatures in October and November led to warnings for homeowners about the potential for wasp nests in their properties even late into the year.
This alteration in the synchrony between host and insect development and winter survival won’t just cause more problems for properties however as whole ecosystems will also be affected. An example of this is the expected proliferation of the green spruce aphid which could lead to significantly more intense and frequent tree defoliation.
By far and away the most concerning impact of climate change in terms of insect populations is the opportunity for foreign insects to move further north to countries, like ours, where previously they would not have survived. This will not only pose risks to our existing ecosystems and insect-life but potentially, like with the case in Norfolk, also to human safety as well.
Some differences in the distribution of certain species have already been observed across the continent, with the native European butterfly’s northern ranges extended and southern ranges reduced. In addition, insect experts have carried out modelling work that suggests even more exotic pests could establish populations in Europe, including the southern pine beetle and the bark beetle Ips typographus.
The Impact of Global Trade
Foreign pests don’t just migrate further north as temperatures increase, they can also be brought here by humans, like with the Black Widow.
The increase in global transportation of timber and wood products, as well as various other products from abroad, makes it more likely that these exotic pests will be brought to this country, while the impact of climate change makes it a more hospitable environment for them in which to survive.
Plant and insect life has evolved and developed within very specific environmental conditions so it is an unfortunate inevitability that global warming at the pace we have seen over the last few decades is going to have major repercussions for these species.
This guest blog was written by John Rooney on behalf of GPM Pest Management – specialists in dealing with all kinds of pest problems throughout London.