Current presence of Maculinea alcon in Navarre confirmed (27/10/2015)

The work performed to diagnose and monitor invertebrates in Navarre’s LIFE TREMEDAL wetlands coordinated/organised by GANASA and carried out by Biosfera Consultoría Medioambiental is providing information of great use to wetland management and turning up some pleasant surprises on the situation of unique, endangered and protected species.

 The latest reason for joy came from the myrmecophilous butterfly Maculinea alcon, of which no sightings had been recorded in Navarre for more than thirty years and reproduction of which has now been confirmed at the Jauregiaroztegi wetland in Auritz-Burguete. This butterfly is associated with wetland meadows in grazing environments, where it completes a complex and rather strange life cycle. This life cycle involves the Marsh Gentian (Gentiana pneumonanthe) as the sole food plant for the early larval stages of the butterfly, following which the larvae need to be collected by a species of host ant (Myrmica) The ants take them to their nest and feed them until they pupate and the adults hatch. This peculiar cycle therefore requires the simultaneous presence of both the food plant and the host ant.

 The situation of this butterfly in Spain was recently revised to almost endangered in the Atlas and Red Book of Endangered Invertebrates. The special situation in Navarre, which may be home to the two subspecies present on the Iberian Peninsula, makes this new population all the more interesting. Their peculiar life cycle and the problems which their conservation entails have led to the adoption of myrmecophilous butterflies as one of the flagship species of European conservation and so their discovery at Jauregiaroztegi further highlights the importance to nature of this Navarrese wetland.

Biologists looking for Maculinea alcon eggs and adults at Jauregiaroztegi as part of the Life Tremedal actions.

Gentian with Maculinea alcon egg and detail at Jauregiaroztegi.