Common Blue (Polyommatus icarus) lives in flowery or grassy, open or wooded, up to alpine meadows across Europe, North Africa, and the Canary Islands.
Fascinating facts about the Common Blue
- Female common blues hoard about 60 % more flavonoid pigments from their host plants than males. These UV-absorbing compounds boost wing colour saturation, making females stand out to patrolling males and also shielding eggs from harmful UV rays. The sex-biased pigment load therefore acts as both a sexual signal and a protective coat, tying diet directly to reproductive success.
- The common blue jumped the Atlantic when an amateur spotted it in Mirabel, Quebec, Canada, after watching the insect from 2005 to 2008. It now thrives in urban patches where bird's-foot trefoil grows. This urban affinity demonstrates how a European grassland specialist can colonise North American cities by exploiting garden-plantings of its native host.
- Common blues see further into the green spectrum than most butterflies, thanks to a duplicated blue opsin paired with a long-wavelength opsin that pushes colour detection up to 560 nm. They can discriminate yellow at 590 nm from blue at 430 nm, though they cannot tell yellow from red at 640 nm.
- A common blue's wings stretch just 28-36 mm (1.1-1.4 in), yet this tiny canvas carries iridescent lilac-blue on the dorsal side and a row of red-orange marginal spots.
- Since the 1970s the common blue's range has slipped by 15 %, and overall its population has shed an estimated 74 % since 1901. The same period saw a 46 % loss of Lotus corniculatus, the butterfly's favourite larval host.
Sources
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At a glance
RangeEurope, North Africa, and the Canary Islands
HabitatFlowery or grassy, open or wooded, up to alpine meadows
DietLegumes and leaves
About the Common Blue
As the warmth of sunlight dances across the wildflower-strewn meadows, the Common Blue butterfly stirs to life, its iridescent wings beating in a hypnotic rhythm as it flits from bloom to bloom. With an effortless elegance, it navigates the intricate tapestry of its natural world, its delicate form belied by a resilience that allows it to thrive in a wide range of habitats. In its fleeting, fluttering existence, the Common Blue embodies the very essence of summer's joy and beauty, a tiny, shimmering jewel that adds depth and richness to the landscape.
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