OLDER folks can conjure up childhood memories of sunny days filled with clouds of butterflies. Over the past 50 years their numbers have dwindled alarmingly, due to habitat loss, changes in agricultural practices and global warming. The monarch is the largest butterfly seen in the UK and one of our rarest migrants. In the US it is listed as Endangered on the IUCN Red List. These iconic butterflies migrate from Mexico and California in the winter to summer breeding grounds throughout the USA and Canada, where they depend on milkweeds as food plants for their caterpillars.
The butterfly effect
Butterflies are important biodiversity indicators and feature in the chaos theory expounded by meteorologist Edward Lorenz in 1963, that the flap of a butterfly’s wings in the Amazonian rain forest can change the weather half a world away. Known as the butterfly effect, it showed that small changes can have large consequences.
