China], euphemus, arcas, arion, arionides ...) by the male bearing on the blue disc of the forewing no other black spots but the discocellular lunule.

(83 a) has a narrow black margin like rebeli, but the blue is very deep and dark, so dull as in true alcon; from the Alps of Switzerland and the Caucasus.

[2] There are five subspecies: There has been controversy over whether Phengaris rebeli, currently regarded as an ecotype within the Alcons, should be listed as a separate species.

The two types are morphologically indistinguishable and molecular analysis has revealed little genetic difference, mostly attributable to localized habitat adaptation.

Alcon larvae leave the food plant when they have grown sufficiently (4th instar, or shedding) and wait on the ground below to be discovered by ants.

[9] Another advantage of cuckoo feeding is that individuals, having pursued a higher degree of social integration, have a higher chance of surviving when a nest is overcrowded or facing food shortage because ants preferentially feed the larvae; compared to the type of scramble competition that can devastate predatory larvae, this contest competition results in much lower mortality.

[11][12] Though the cuckoo strategy has its advantages, it also comes with important costs; with greater host ant specialization comes much more limited ecological niches.

Over time, some ant colonies that are parasitized in this manner will slightly change their larva chemicals as a defence, leading to an evolutionary "arms race" between the two species.

[13][14] Generally, Lycaenidae species which have a myrmecophilous relationship with the ant genus Myrmica are locked to primary host specificity.

On detecting a P. alcon larva the wasp enters the nest and sprays a pheromone that causes the ants to attack each other.