Powerful and fast in flight, the purple emperor is a large woodland butterfly with a wingspan of up to 8.4cm. It uses its long proboscis to obtain liquid from muddy puddles and from carrion, but it also takes the honeydew - a clear, sugary fluid - that aphids deposit on leaves. While the purple emperor feeds, it often closes its wings to conceal the distinct colours of its uppersides, making itself less noticeable to predators.