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Maculinea alcon (Lepidoptera, Lycaenidae) en Brenne. Bilan de trois années d'observations. Analyse stationnelle des facteurs pouvant conditionner le succès de la reproduction. In : Premières rencontres entomologiques de la région Centre du 28 octobre 2000

Auteurs : Colombo (Jean-Baptiste), Dreuillaux (Jean-Michel), Dumeige (Bruno), Lhonoré (Jacques Élie), Louveaux (Alain) et Abbé (Pierre)

Année de publication : 2001
Publication : Symbioses
Volume : 4
Pagination : 5-10

Résumé :

A small population of the large blue butterfly Maculinea alcon settled in a marsh of the north Brenne region is under investigations since three years. This population is very isolated and was estimated each year, to tenth pairs which is a fright for its perennity. Since five years the Brenne Nature land is conducting a conservatory management on the site. The main objective of the project study is to propose some specific butterfly conservation measures for this butterfly. The decline of the population is partly due to an excess of rain in July since three years and part also influenced by local environmental conditions which are becoming unfavourable. The habitat of the butterfly is a peat meadow which is, accordingto the micro topography, a molinion (.Molinia caerulea and Schoenus nigricans ) or a cladiaie (.Cladium mariscus) in the wetter parts of the marsh. Gentiana pneumonanthe is an abounding host plant at the study site. More than 1.000 Marsh Gentian were counted ; but they seem to be in a state of senescence with regard to their height and color of the flowers. The gentian's settlement in the meadow and the number of M. alcon' & eggs deposited on the flowers have been kept under study during two years. We stressed that the egg clusters were not deposited at random in the habitat but concentrated in high density of Marsh Gentian patches. It should enhance the probability of being discovered and adopted by ants ; anoutpout that could condition the reproductive success of the butterfly