Alcon Blue

The Alcon Blue (Phengaris alcon/Gentiaanblauwtje) is a scarce and vulnerable butterfly of our wet moorland. Like some other species of Lycaenidae, its larva (caterpillar) stage completely depends on support by ants of genus Myrmica. It is therefore known as a myrmecophile.
The butterfly lays its eggs onto the Marsh Gentian (Gentiana pneumonanthe/Klokjesgentiaan); see the white tiny spot on the photo. The caterpillars eat no other plants and leave the food plant when they have grown sufficiently (4-th instar) just waiting on the ground below to be discovered by ants. The larvae emit surface chemicals (allomones) that closely match those of ant larvae, causing the ants to carry the Alcon larvae into their nests and place them in their brood chambers, where they are fed by worker ants, a method known as the “cuckoo” strategy. When the Alcon larva is fully developed it pupates. Once the adult hatches (next summer) it must run the gauntlet of escaping because the ants now recognize the butterfly to be an intruder.
This miraculous process repeats itself for thousands of years on our moorlands. However, in the last few decades many Alcon Blue populations have disappeared. Predictions are that they will be extinct within 10 – 20 years. Nature protectors do what they can to prevent it.

* Canon EOS 7D, 100mm/f2.8; ISO-400, f4.5, 1/160s; +0.3 stop.