Small Tortoiseshell

The Small Tortoiseshell Butterfly (Aglais urticae)
Both sexes have bright orange wings with a black border flecked with blue as well as black spots makes this one of our most instantly recognisable butterflies.  The underside is brown and dark grey providing excellent camouflage.   Despite once being a common sight this butterfly is now in trouble and has suffered a 75% decline in the past decade.
The primary reason for this is to be found on the feeding plant of its larvae,  the Common Stinging Nettle, and is due to the recent arrival in Britain (1999) of the a parasitoid fly, Sturmia bella, which lays its eggs on the stinging nettle.  These are then ingested by the Small Tortoiseshell’s larvae.  The fly’s larvae then develop within the caterpillars and emerge just as these pupate killing them in the process.  The other obvious reason for the continued decline is the decreasing stands of stinging nettles.
With a wingspan of between 45-62mm across the Small Tortoiseshell is a strong flyer in bright sunshine but is relatively easy to approach when feeding. It will be found in large numbers in suitable habitats and will be found on the wing from late March until the end of October. The peak month is August. The adults still on the wing at the end of the season will hibernate which explains why this butterfly can be seen as early as March. The eggs are laid in May and July. Larvae are to be found from May until August and the pupae are seen in June, August and September. They do not overwinter in these immature stages.