Flies keep landing on North Sea oil rigs

Summary

On a North Sea oil rig several years ago, an engineer noticed a strange phenomenon. A cloud of insects would descend from the sky and land on the upper reaches of the platform. There were thousands of them, carpeting the superstructure and barely moving. They would sit there for a few hours, then suddenly they would all rise up into the sky and fly off again. The engineer, whose name was Craig Hannah, was also a keen naturalist and photographer. He saw the same thing happening repeatedly and wondered if it would be of interest to insect researchers. This led him to the University of Exeter’s Centre for Ecology and Conservation, to which we are both affiliated. Craig diligently collected small specimen-tubes of flies at the rig, which is in the UK Britannia oil field, and they started arriving regularly on our desks. We’ve spent the past few years studying them, and the results have now been published for the first time. The insect cloud mostly consisted of hoverflies. Hoverflies are a stripey little class of winged insects that sometimes get mistaken for wasps or hornets. They play an unsung role as nature’s pest controllers, gobbling up aphids on plants, and also have another claim to fame: they are the second most important pollinators after bees. Unlike bees, which are territorial creatures that generally stay in their patch, hoverflies can move over great distances. If you’re wondering why they don’t become the king pollinators as a result, it’s to do with their larvae. Bee larvae depend on nectar and pollen, so when bees land on flowers, they are collecting for the hive. Infant hoverflies, on the other hand, eat aphids, leaving adult hoverflies to gorge on all the pollen and nectar themselves. Long insect journeys The intrepid Painted Lady. Marek Mierzejewski It has been shown before that insects can carry pollen for many miles. Painted Lady butterflies, for instance, have been shown to travel from west Africa all the way to French Guiana in South America. The ...