Insects Are Good For Us
When we set out four years ago to plant trees at Lofftwen one of the objections was that these trees would attract more insects, which in turn would put off tourists from visiting the area. It seemed an odd criticism at the time, but on reflection I’m grateful, as it made me realise just how little thought I had given to the relationship between insects and trees.
On an entirely superficial level, insects, especially biting insects, can be insanely annoying. But on a more fundamental level, a healthy population of insects is essential to so many elements of our lives, from free pollination of our crops, saving Britain £690 million a year in the process if we had to do it by hand (a proposition that gets closer by the day), to providing a protein bonanza for all those sitting above them in the food chain.
You’re unlikely to hear anyone with a straight face objecting to increased bird life in the countryside; bird tourism is now one of the fastest growing tourism sectors with one report estimating £400 million is now spent annually on birding in the UK. But saying “no” to increased insects is tantamount to saying “no” to more birds. And our birds are under attack like never before. Since 1970, which was already a low baseline, we’ve lost 90% of corn buntings, 97% of tree sparrows, 60% of yellow wagtails, 90% of nightingales, and 88% of willow tits, just to mention a few. And the declines for many of these species are speeding up, not slowing down.
“A devastating collapse in the invertebrate food chain is the greatest driver of contemporary bird decline in Britain. Yet the absence of that food chain is invisible to us – a problem we often overlook because its scale is too enormous to be comprehended. Insects fade without fanfare as they are tidied and removed from our lives. There is no drama to their departure. After a generation, nobody remembers – nobody expects. ”
Reasons behind these declines are of course complex and varied. But one of the main contributory factors for many is a loss of mature, diverse thorny scrubland with its mix of different trees of different ages punctured by pockets of grazed clearings. Such habitats provide physical protection from predators alongside a constant larder of different fruits and seeds at different times of the year. They also create prime real estate for lots of insects munching away on a smorgasbord of leaves and decaying wood.
Oak is perhaps the most insect-rich tree of all. A mature oak can support around 380 of Britain’s 900 moths. Willow is the second richest wildland tree, capable of supporting 266 different species of insect, including more moth caterpillars than any other tree. What’s more, it can do this from a much younger age than oak. Silver and downy birch come third with 229 different insect species. Thorny bedfellows, hawthorn and blackthorn, support 149 and 109 insect species respectively. Crab apples, with 93 species, are hugely rich in hornets and fly species, and much of this diversity is shared with domesticated apple trees too. Wetland-loving alder has 90 associated insect species, and hazel 73. And so, the list goes on.
Anecdotally, it feels like we are seeing a large increase in invertebrate numbers at Lofftwen; as one neighbour remarked a year or two ago “I’ve never seen so many butterflies before!”. Prior to lockdown we were talking to potential partners about how to go about scientifically measuring changes in insect numbers. These are conversations we will resurrect once lockdown eases. If they have increased, then we think this probably has more to do with the returning wetlands, wildflower meadows and increased scrubland habitat, as the trees we planted are still very young. This means we are nowhere near our capacity for insect numbers at Lofftwen, and as the trees mature we hope to see these numbers continue to rise, alongside an increase in the reptiles, bats and birds that will feed on them, attracting in turn larger predators, followed by the ultimate apex predator of all, wildlife-seeking tourists.
Sources for this news item included:
https://pelagicpublishing.com/products/rebirding-restoring-britains-wildlife-macdonald-pelagic-9781784272179
https://www.responsibletravel.org/docs/Market%20Analysis%20of%20Bird-Based%20Tourism.pdf
http://www.countrysideinfo.co.uk/woodland_manage/tree_value.htm