A hoverfly on a cluster of yellow mustard flowers. (Credit: Dave Hansche/Shutterstock)

Billions of hoverflies from Europe descend on southern Britain each spring. The black and yellow striped bugs are no more than half an inch in length but make the long trek to Britain for the summer.

Once they arrive, the hoverflies pollinate flowers and lay eggs. The fly populations have remained stable unlike those of honeybees and other insects, which have dropped in recent years, researchers find i