A Unique Population in a Unique Area: The Alcon Blue Butterfly and Its Specific Parasitoid in the Białowieża Forest.

Ewa Pirożnikow,Piotr Nowicki,Marcin Sielezniew,Izabela Dziekańska

doi:10.3390/insects11100687

Ewa Pirożnikow, Piotr Nowicki + Show 2 more

Open Access

https://doi.org/10.3390/insects11100687

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Abstract

Caterpillars of the Alcon blue butterfly Phengaris alcon are initially endophytic and feed inside the flowerheads of Gentiana plants, but complete their development as social parasites in the nests of Myrmica ants, where they are fed by workers. Its specific and complicated ecological requirements make P. alcon a very local, threatened species, sensitive to environmental changes. We investigated an isolated and previously unknown population in an area of high nature value-the Białowieża Forest (NE Poland). Using the mark-release-recapture method we estimated the seasonal number of adults at 1460 individuals, and their density (850/ha) was the highest among all populations using G. pneumonanthe studied so far. The site is also unique due to the presence of the specific parasitoid Ichneumon cf. eumerus, and parasitoids are considered the ultimate indicators of the biodiversity of Phengaris systems. Since 75.5% of P. alcon pupae were infested we could estimate the seasonal population of adult wasps at about 4500 individuals. The high abundance of both P. alcon and its parasitoid may be explained by favorable habitat characteristics, i.e., the strong presence of host plants and the high density of nests of Myrmica scabrinodis, which is the only local host ant of the butterfly.

Highlights

European representatives of the genus Phengaris Doherty (Lepidoptera, Lycaenidae), which is a senior synonym of Maculinea Van Eecke [1], are considered as flagship priorities in butterfly conservation, along with Queen Alexandra’s birdwing of Papua New Guinea, and the Mexican overwintering sites of monarchs [2]
In 2016 we discovered a large population in an area of high nature value—the Białowieża Forest (NE Poland)
P. alcon has never been recorded in the Białowieża Forest before, including the Belarussian part of the area [42]

Summary

Introduction

European representatives of the genus Phengaris Doherty (Lepidoptera, Lycaenidae), which is a senior synonym of Maculinea Van Eecke [1], are considered as flagship priorities in butterfly conservation, along with Queen Alexandra’s birdwing of Papua New Guinea, and the Mexican overwintering sites of monarchs [2]. All four European species are threatened on a continental scale [3] and three of them are listed in the Annexes of the Habitat Directive. Large blues attract the attention of conservationists and scientists due to their complicated and peculiar life history related to obligatory myrmecophily [4,5,6]. In contrast to most other butterflies they require two different resources to complete their development.

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