Host plant use drives genetic differentiation in syntopic populations of Maculinea alcon

• Published in: PeerJ (San Francisco, CA) Vol. 4; p. e1865
• Main Authors: Tartally, András, Kelager, Andreas, Fürst, Matthias A., Nash, David R.
• Format: Journal Article
• Language: English
• Published: United States PeerJ. Ltd 31.03.2016; PeerJ, Inc; PeerJ Inc
• Subjects: Animal behavior; Bayesian analysis; Butterflies & moths; Conservation Biology; Conservation units; Dispersal; Disruptive selection; Ecology; Ecotypes; Entomology; Evolutionary Studies; Flowering; Formicidae; Gene flow; Genetic markers; Genetics; Gentiana; Host plants; Hymenoptera; Immigration; Lepidoptera; Lycaenidae; Maculinea arion; Microsatellites; Myrmica; Parasites; Phenological separation; Phenology; Phylogenetics; Population genetics; Conservation units; Myrmica; Phenological separation; Host specificity; Immigration; Disruptive selection; Maculinea rebeli; Gentiana
• DOI: 10.7717/peerj.1865
• ISSN: 2167-8359

The rare socially parasitic butterfly Maculinea alcon occurs in two forms, which are characteristic of hygric or xeric habitats and which exploit different host plants and host ants. The status of these two forms has been the subject of considerable controversy. Populations of the two forms are usually spatially distinct, but at Răscruci in Romania both forms occur on the same site (syntopically). We examined the genetic differentiation between the two forms using eight microsatellite markers, and compared with a nearby hygric site, Şardu. Our results showed that while the two forms are strongly differentiated at Răscruci, it is the xeric form there that is most similar to the hygric form at Şardu, and Bayesian clustering algorithms suggest that these two populations have exchanged genes relatively recently. We found strong evidence for population substructuring, caused by high within host ant nest relatedness, indicating very limited dispersal of most ovipositing females, but not association with particular host ant species. Our results are consistent with the results of larger scale phylogeographic studies that suggest that the two forms represent local ecotypes specialising on different host plants, each with a distinct flowering phenology, providing a temporal rather than spatial barrier to gene flow.