LONG DISTANCE FLIES

When most of us think of migrating animals, it is of birds, bats, a few terrestrial mammals, some fish such as salmon and perhaps occasional butterflies like the painted lady and monarch. It is seldom flies which come to mind, but work by Hawkes, Menz & Wotton[1] reveals that we should add many species of fly to the great migrators of the natural world. 

The research, which the authors note is biased towards Europe, revealed that 46% of 130 families of true flies (the Diptera which have a single pair of wings) display evidence of migration, with hoverflies (Syrphidae) being particularly prominent, which is important because of their role as pollinators. Flies can travel hundreds or even thousands of kilometres in huge numbers[2].

As usual these days, there are problems for migratory flies due to climate change, pesticide use, habitat destruction and other anthropogenic influences – I have mentioned many times the disastrous crash of many insect populations we have seen in recent years. But we should not forget how important flies are in the context of biodiversity and ecosystem services such as waste decomposition as well as pollination. In terms of our warming world, the researchers theorise that cross-pollination over large distances might even allow plants to acquire genetic traits to help them adapt to climate change.

[1] https://doi.org/10.1101/2024.03.04.583324

[2] The longest recorded migration seems to be that of Eupeodes americanus, an American hoverfly which travels over 3000 km from Canada to the south-east USA!