Written by Lucy Brzoska
I half-glanced at the orange butterfly, expecting to see a Wall (Lasiommata megera), an abundant species on Montjuic. After a double-take, I realised it was something else altogether. Having looked wistfully at so many photographs of this species, recognition was instant. I was moving carefully forward with the camera, when a jogger pounded past, and the Plain Tiger was gone.
But a quick scramble up the slope, behind a bush of broom, revealed large clusters of Coronilla de Fraile (“Friar’s pate” – Globularia alypum), and there, feeding calmly, were three Plain Tigers.
D. chrysippus is an extremely common butterfly species in Africa and Asia, but a recent arrival in Iberia. A strong migrator, after emerging, each generation moves on. Well-established in Andalucia, they have been recorded all along the Mediterranean coast as far north as Roses on the Costa Brava. JM Sesma of Biodiversidad Virtual suggests the ones I saw were the progeny of Tigers recorded in the Delta del Ebro two months previously.
The Plain Tiger is a cooperative butterfly to photograph. Rather than erratic flight, or camouflage, it protects itself by toxicity, so readily displays its colours to potential predators. The Tiger’s wings, with a range of tones – from orange to russet and brown – sharply outlined in black, are beautiful, but best of all, in my opinion, is the body and head, covered in striking white polka dots. The males are distinguished by a prominent white spot on the hind underwing, edged in black, which is a concentration of scent scales used for mating.
Interestingly, the spread of D. Chrysippus in Iberia has been abetted by the widespread invasion of a garden escapee, Gomphocarpus fruticosus, a member of the Milkweed family. Danaid caterpillars feed on Milkweed plants, storing up the toxic alkaloids from their milky sap, enough to make an unwary predator vomit.