METAMORPHOSIS MONDAY,

1.45PM, RADIO 4 ★★★★ Morpho butterflies are among the largest in the world, with a wingspan of up to eight inches. You’d think that their wings are coloured blue – but they aren’t. The production of blue is due to elaborate shapes on their wings that reflect light. Dr Erica Mcalister marvels at the beauty of these butterflies (left) and the science behind their spectacular iridescence.