Phengaris rebeli  Phengaris rebeli (formerly Maculinea rebeli), common name mountain Alcon blue, is a species of butterfly in the family Lycaenidae. It was first found and described in Styria, Austria, on Mount Hochschwab around 1700. Although it was initially classified as a subspecies of "P. alcon", a European researcher, Lucien A. Berger, designated it as a separate species in 1946. Genetic similarities between "P. rebeli" and "P. alcon" have led many researchers to argue that the two are the same species and differences are due to intraspecific variation. Although "P. rebeli" is found across the Palearctic (see subspecies), it is difficult to determine the species' precise range due to confusion with "P. alcon". Behavioral ecologists have found its role as a brood parasite to be of particular interest as, unlike many brood parasites, it does not directly oviposit in the hosts' nests. "P. rebeli" parasitizes the colony ant species "Myrmica schencki" as a larva by using chemical mimicry to trick the ants into believing that they are ant larvae; thus, the ants bring "P. rebeli" caterpillars back to their nests and feed them. "P. rebeli" is dependent on the plant "Gentiana cruciata" early in its life cycle and is vulnerable to parasitism by "Ichneumon eumerus" while inside the nest of "M. schencki". It was placed on the IUCN Red List in 2000 and is classified as a species vulnerable to extinction. The genus "Phengaris" was previously considered a subgroup within the genus "Maculinea" (explaining why "P. rebeli" was formerly known as "M. rebeli") and the "Maculinea-Phengaris" clade is thought to be a section within "Glaucopsyche". There are three groups within this "Maculinea-Phengaris" clade: the "alcon" group, the "teleius" group, and the "Arion-Phengaris" group. The groups are divided based on their alternative parasitization strategies of the host ants. The predatory strategy (in which the caterpillar consumes the host ants) and cuckoo strategy (in which the caterpillars feed off of the ants' regurgitation) are derived characteristics from the "alcon" group, with the predatory strategy having evolved from the "teleius" group and the cuckoo strategy having evolved from the "arion-Phengaris" group.