Harlequin ladybird, fly away home

I was shocked some years ago to discover, as I scratched bites on my ankles on holiday on Maui, that mosquitoes are not native to Hawaii. They first arrived in the 1820s, in barrels of water from a visiting ship. Of course, the climate was perfect for them, and they settled in very happily. But we could have had tropical islands free of them  — and the risk of diseases they can carry.

The story of invasive species is often one of accidental introduction. Or of misguided humans who think they are somehow setting a creature ‘free’ — like the group of Buddhists who released hundreds of foreign lobsters from a boat off the English coast in 2015 as part of a religious ceremony. (They were later fined £15,000 for environmental damage, and extensive efforts were made to recover the crustaceans.) Or even more humbly, those who put their goldfish in a local stream — helping to contribute to the population of invasive fish.