I have posted this photo of a Small Tortoiseshell butterfly (Aglais urticae), to draw attention to it's decline here in the UK.
Numbers of this once very common butterfly have suffered a dramatic decline, and are down 80% in the UK. The problem may be linked to climate change, but another suspect is the tiny parasitoid fly Sturmia bella, first noted in Britain in 1999. Its arrival from Southern Europe is either the result of climate change or an unwitting introduction from caterpillars brought in from Europe.
Sturmia bella eggs are increasingly found on the nettles that the Small Tortoiseshell’s caterpillars feed on. It is suspected that the caterpillars are consuming the eggs which then hatch and develop inside them as they reach the cocoon stage, killing the host.
Also, after the wet summers in recent years, Britain's butterflies are in desperate need of good weather in future years, or they may experience a population "catastrophe"!
It will be a shame if this beautiful butterfly disappears from our gardens in the UK.