I usually see these beautifully coloured butterflies in my local fields, but there are distinct differences between the males and the females. The male upper side is bright blue with a strong violet tinge and plain white borders. The female colouration is variable, ranging from rusty-brown to violet with orange submarginal markings. The fringes range from brown to white. Wingspan 35mm.
The caterpillar feeds on Bird’s-foot Trefoil, Restharrow, and a wide range of low-growing leguminous plants. The caterpillars are milked by ants for their honeydew secretions in return for their care and protection from predation.
It flies April to October in two or three broods. Found in rough grassy places, including roadside verges and woodland clearings. By far Britain’s most widespread blue butterfly. Common and resident.
Photographs of female Common Blue (Polyommatus icarus) taken June 2007, July 2010 and July 2011 in local field, Staffordshire. Male taken August 2015, Daddyhole Plain, Torquay, Devon. © Pete Hillman 2007, 2010, 2011. 2015. Cameras used Sony Cyber-shot DSC-W1, Panasonic Lumix DMC-FZ38, and Nikon D3200, with Sigma 105mm macro lens.