Patterns of host use by brood parasiticMaculineabutterflies across Europe

Abstract

The range of hosts exploited by a parasite is determined by several factors, including host availability, infectivity and exploitability. Each of these can be the target of natural selection on both host and parasite, which will determine the local outcome of interactions, and potentially lead to coevolution. However, geographical variation in host use and specificity has rarely been investigated. Maculinea (= Phengaris ) butterflies are brood parasites of Myrmica ants that are patchily distributed across the Palæarctic and have been studied extensively in Europe. Here, we review the published records of ant host use by the European Maculinea species, as well as providing new host ant records for more than 100 sites across Europe. This comprehensive survey demonstrates that while all but one of the Myrmica species found on Maculinea sites have been recorded as hosts, the most common is often disproportionately highly exploited. Host sharing and host switching are both relatively common, but there is evidence of specialization at many sites, which varies among Maculinea species. We show that most Maculinea display the features expected for coevolution to occur in a geographic mosaic, which has probably allowed these rare butterflies to persist in Europe. This article is part of the theme issue ‘The coevolutionary biology of brood parasitism: from mechanism to pattern’.

Changes in host ant communities of Alcon Blue butterflies in abandoned mountain hay meadows

“…Whether this represents true species loss or a temporal change in a plastic phenotype remains to be clarified. The continued or increasing dominance of M. scabrinodis on three of the sites is noteworthy, but is difficult to interpret as there seem to be at least two divergent lineages within this species that differ in their habitat requirements (Ebsen et al ., ) and may also differ in their suitability as hosts of Maculinea butterflies (Tartally et al ., ).…”

“…There was no evidence for host ant specificity for M. alcon X on the four sites examined, despite reasonable sample sizes of Myrmica nests of different species, which often limits the ability to detect heterogeneity in host use (Tartally et al ., ). This may also reflect the particular Myrmica community composition on these sites, as although there were large changes in the relative abundance of different species, the proportion of species that had been recorded as local hosts of M. alcon X remained high.…”

“…Current literature (Tartally et al ., ) distinguishes three forms of M. alcon , the hygrophilic ( M. alcon H ), the xerophilic ( M. alcon X ) and the Alpine ( M. alcon form rebeli ). For a long period M. alcon X was widely referred to as ‘ M. rebeli ’; however, this assertion has been shown to be misleading (Habeler, ; Kudrna & Fric, ; Tartally et al ., ; Koubínová et al ., ; Bereczki et al ., ).…”

Phylogeography and cryptic speciation in theMyrmica scabrinodisNylander, 1846 species complex (Hymenoptera: Formicidae), and their conservation implications

“…At the opposite end of the spectrum, the lack of clear differentiation that we find between M. lonae and M. sabuleti also has implications for the conservation of Maculinea arion ( Linnaeus , 1758), which has been recorded as using both ants as hosts (Sielezniew et al ., ; Tartally et al ., ), and where there is an apparent switch from M. sabuleti as the main host to exclusive use of M. lonae as a host in the northern part of the butterfly's range (Tartally et al ., ). If these two ants are not separate species, then it may ease the conservation of this species in northern areas.…”

“…(3) The recent emergence of at least one supercolonial invasive species – Myrmica rubra in North America (Groden et al ., ; Gammans et al ., ), a syndrome that may also occur in native populations of M. rubra and several other species (van der Hammen et al ., ). (4) The extensive but highly variable suitability of species as hosts for Maculinea van Eecke , 1915 (= Phengaris Docherty, 1891) butterflies (Tartally et al ., ; see also the other papers in this special edition), which are icons of insect conservation (Thomas et al ., ; Stearns & Stearns, ).…”