Why we need insects... Insects have declined by 75% in the past 50 years – and the consequences may soon be catastrophic. Biologist Dave Goulson reveals the vital services they perform
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I am haunted by the knowledge that these creatures are in decline. It is 50 years since I first collected those caterpillars in the school playground, and every year that has passed there have been slightly fewer butterflies, fewer bumblebees – fewer of almost all the myriad little beasts that make the world go round. These fascinating and beautiful creatures are disappearing, ant by ant, bee by bee, day by day. Estimates vary and are imprecise, but it seems likely that insects have declined in abundance by 75% or more since I was five years old. The scientific evidence for this grows stronger every year, as studies are published describing the collapse of monarch butterfly populations in North America, the demise of woodland and grassland insects in Germany, or the seemingly inexorable contraction of the ranges of bumblebees and hoverflies in the UK.
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The importance of insects is often justified in terms of the ecosystem services they provide, which can be ascribed a monetary value. Pollination alone is estimated to be worth between $235bn and $577bn a year worldwide (these calculations aren’t very accurate, hence the wide difference between the two figures). Financial aspects aside, we could not possibly feed the growing global human population without pollinators. We could produce enough calories to keep us all alive, since wind-pollinated crops such as wheat, barley, rice and maize comprise the bulk of our food, but living exclusively on a diet of bread, rice and porridge would quickly see us succumb to deficiencies of essential vitamins and minerals. Imagine a diet without strawberries, chilli peppers, apples, cucumbers, cherries, blackcurrants, pumpkins, tomatoes, coffee, raspberries, courgettes, runner beans and blueberries, to name just a few. The world already produces fewer fruit and vegetables than would be needed if everybody on the planet were to have a healthy diet. Without pollinators it would be impossible to produce anywhere near the “five a day” fruit and veg we all need.
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https://www.theguardian.com/environm...tm_source=digg