Maculinea Arion Research Articles

The genome sequence of the Large Blue butterfly, Phengaris (Maculinea) arion (Linnaeus, 1758)

We present a genome assembly from a female Phengaris arion (the Large Blue butterfly; Arthropoda; Insecta; Lepidoptera; Lycaenidae). The genome sequence is 544.50 megabases in length. Most of the assembly is scaffolded into 23 chromosomal pseudomolecules, including the Z sex chromosome. The mitochondrial genome has also been assembled and is 15.7 kilobases in length.

Landscape properties and density dependence shape the movement patterns of three threatened butterflies

ContextConservation of endangered species necessitates an in-depth understanding of their ecological requirements. Particularly in landscape ecology, the behavioural tendencies of threatened butterfly species in Gotland, a biodiversity-rich island in the Baltic Sea, become crucial.ObjectivesThe primary aim of this study was to elucidate the movement patterns of three threatened butterfly species—Euphydryas aurinia, Parnassius apollo, and Phengaris arion—in Gotland and to identify the influence of specific land characteristics on these patterns.MethodsOur study, conducted from 2017 to 2020 across 60 km2 in Gotland, involved detailed capture-mark-recapture (CMR) efforts of 29,584 captures including 16,223 unique butterflies. We investigate the departure and arrival events of butterflies, specifically focusing on the associations between movements when individuals leave or enter a hectare grid different from their previously recorded location and key landscape features: open vegetated land, ground moisture, and forest cover. We model landscape features to examine the interplay between these and butterfly movement patterns, providing insights into preferred landscape features and conservation strategies.ResultsAmong the 4821 arrivals and 5083 departures documented, the species exhibited differential responses to the evaluated habitat features. Both E. aurinia and P. apollo displayed a positive density-dependent dispersal, while P. arion’s movements were not significantly associated with any of the examined habitat features. Landscape properties like open vegetated land and ground moisture index statistically influenced the likelihood of arrival and departure.ConclusionsThe study accentuates the relationship between land cover and the behavioural tendencies of the subject butterfly species. It has broader implications for the targeted habitat management strategies that would benefit threatened butterfly populations in Gotland.

Long‐distance movements, large population sizes and density‐dependent dispersal in three threatened butterfly species

Abstract This study investigates the ecology of three threatened butterfly species on a 60 km2 site in Gotland, Southeast Sweden, using mark–recapture methods from 2017 to 2020. Nearly 30,000 captures were recorded, with average lifespans of 6 days for Euphydryas aurinia (Lepidoptera: Nymphalidae) and Parnassius apollo (Lepidoptera: Papilionidae) and 2 days for Phengaris arion (Lepidoptera: Lycaenidae). Population size, density and maximum flight distances varied between species, with E. aurinia at 7.2 km, P. apollo at 6.4 km and P. arion at 2.5 km. Movement data showed the lognormal kernel fit better than gamma, negative exponential and half‐normal kernels for distance travelled per time unit across species and sexes. Generalised linear models revealed significant positive density‐dependent emigration and negative density‐dependent immigration in all three species. Despite available suitable habitats, these species face threats from limestone quarry expansions, agricultural intensification, modified forestry practices, natural succession and climate change, highlighting the need for proactive conservation and strategic habitat management.

Contribution to the knowledge of the butterfly fauna (Lepidoptera: Papilionoidea) of Central Slovenia

The southwestern Posavsko hills and northern Suha krajina are among the least studied areas regarding the butterfly fauna in Slovenia. To fill this knowledge gap, we selected all unpublished records of butterflies since 2014, in addition to the focused field surveys performed in the 2019–2022 period. We recorded a total of 105 butterfly species, presenting almost 60% of all species found in Slovenia. Among the species found, there are several habitat specialists of high conservation importance, e.g., Leptidea morsei, Euphydryas aurinia, Parnassius mnemosyne, Phengaris arion, Carcharodus floccifera, Lycaena dispar. Locations harbouring these species and those with the highest species richness are of great importance for preserving the diverse butterfly fauna of the region.

Genome assembly of 3 Amazonian Morpho butterfly species reveals Z-chromosome rearrangements between closely related species living in sympatry.

The genomic processes enabling speciation and species coexistence in sympatry are still largely unknown. Here we describe the whole-genome sequencing and assembly of 3 closely related species from the butterfly genus Morpho: Morpho achilles (Linnaeus, 1758), Morpho helenor (Cramer, 1776), and Morpho deidamia (Höbner, 1819). These large blue butterflies are emblematic species of the Amazonian rainforest. They live in sympatry in a wide range of their geographical distribution and display parallel diversification of dorsal wing color pattern, suggesting local mimicry. By sequencing, assembling, and annotating their genomes, we aim at uncovering prezygotic barriers preventing gene flow between these sympatric species. We found a genome size of 480 Mb for the 3 species and a chromosomal number ranging from 2n = 54 for M. deidamia to 2n = 56 for M. achilles and M. helenor. We also detected inversions on the sex chromosome Z that were differentially fixed between species, suggesting that chromosomal rearrangements may contribute to their reproductive isolation. The annotation of their genomes allowed us to recover in each species at least 12,000 protein-coding genes and to discover duplications of genes potentially involved in prezygotic isolation like genes controlling color discrimination (L-opsin). Altogether, the assembly and the annotation of these 3 new reference genomes open new research avenues into the genomic architecture of speciation and reinforcement in sympatry, establishing Morpho butterflies as a new eco-evolutionary model.

Phylogeography reveals the origin of the two phenological forms of large blue, Phengaris arion (Lepidoptera: Lycaenidae)

Abstract Our main goal was to investigate the phylogeography of the butterfly Phengaris arion to reveal the evolutionary origin of its ‘spring’ and ‘summer’ forms. Molecular analyses based on highly variable microsatellites, together with Wolbachia screening, were carried out on 34 populations in Europe. We found three well-defined genetic lineages of different origins: the Apennine, the central and the eastern. The highly distinct Apennine lineage is limited by the Alps and evaluated as an Evolutionary Significant Unit (ESU). Therefore, the taxon name ligurica, described from the Ligurian coast (Italy), should not be applied to denote the ‘summer form’ of the Pannonian region. The central lineage is limited by the Carpathians and the most eastern ranges of the Alps, and lacks major range fluctuations related to glaciations, although there is evidence for extra-Mediterranean refugia in the Carpathian Basin. The eastern clade could have had refugia in central Asia. Our results exclude the potential allopatric origin of the ‘spring’ and ‘summer’ arion, and support the hypothesis that the existence of the two forms could be a result of local adaptation to the distinctive phenology of host plant flowering which is manifested in the genetic differences between them. Wolbachia infection has been ruled out as a driver of sympatric speciation in P. arion.

Intersexual Differences in Behaviour and Resource Use of Specialist Phengaris teleius Butterflies.

Simple SummaryIn this study, we compared intersexual differences in behaviour and resource use of well-known Scarce Large Blue butterflies. The results indicated that females take short, but exceptionally regular flights, exploring available resources for oviposition. Males took longer, less regular flights, characterised by frequent interactions in search for receptive females. Interestingly, interactions between conspecific butterflies of the investigated species lasted significantly longer than with other species, especially when different sexes were involved. This suggests that individuals were able to quickly and efficiently recognise potential mating partners. Finally, the focal species showed strong association with its larval host plant while resting and nectaring, and less so with other plants with similarly coloured and shaped flowers. Females were particularly strongly restricted to the larval host plant, which provides some evidence that their sensory system shows neural limitation towards this valuable resource.Although the behaviour of the Large Blue butterflies of the genus Phengaris (= Maculinea) is relatively well studied, most empirical data come from investigations of their dispersal and oviposition. Here, we assessed overall intersexual differences in resource use by tracking Phengaris teleius (Bergsträsser, 1779) individuals and recording the duration of their behaviours. Females were characterised by frequent, short flights, and devoted more time to resting and oviposition. Males engaged in numerous, but usually short interactions, and spent most of the time in flight exploring their surroundings for receptive females. Their average flight time was significantly longer compared to females. Average feeding time did not differ between the sexes but was shorter when butterflies were feeding on Sanguisorba officinalis L. Intraspecific interactions within P. teleius were three times longer than those with other insect species, and interactions between sexes were particularly long lasting. Significantly shorter interspecific interactions imply that butterflies can easily recognise conspecifics and differentiate between sexes, which offers obvious fitness benefits. Both sexes, but especially females, showed strong association with their larval host plant, and less so with other flowers of similar colour and shape. Females predominantly used their host plant for feeding, which possibly indicates neuro-sensory constraints towards this resource.

Butterfly diversity (Lepidoptera: Papilionoidea) of Mt. Blegoš and Mt. Koprivnik (Škofjeloško hribovje, Slovenia)

An overview of the surveys of butterfly fauna of Mt. Blegoš, Mt. Koprivnik and their surroundings is provided. In 2018, 14 surveys were performed and 80 butterfly species on eight transects recorded in the process. Additional surveys in 2019 and 2020 yielded 5 additional butterfly species. Among the butterflies observed, Parnassius mnemosyne, Lycaena hippothoe, Euphydryas maturna, Euphydryas aurinia, Melitaea britomartis, Melitaea diamina, and Pyrgus alveus are identified as vulnerable species, while both Phengaris arion and Phengaris alcon are classified as endangered species in Slovenia. The latter was found on two occasions in July 2018 and July 2020 on a single locality. Eggs of P. alcon were found on the host plant Gentiana cruciata at the same locality. Despite the fact that many species characteristic of higher altitudes were observed, like Aricia artaxerxes, Pyrgus alveus, Erebia stiria and Lasiommata petropolitana, other, which had still been present a few decades ago, were not found (Parnassius apollo and Boloria pales). In this article, the problem of loss of important butterfly habitats in the region due to overgrowing, and the negative impacts of overgrazing is also highlighted.

Disentangling the effects of host resources, local, and landscape variables on the occurrence pattern of the dusky large blue butterfly (Phengaris nausithous) in upland grasslands

Determining the effects of local and landscape drivers on endangered species and predicting potential suitable habitats for their persistence is crucial for effective conservation management. Here, we applied a multi-scale approach to disentangle the effects of host resources, local, and landscape variables on the occurrence pattern of Phengaris (= Maculinea) nausithous in semi-natural upland grasslands. Our approach comprised the assessment of host parameters (plant cover, density, height, flower heads density, ant nest density, ant colony size), local grassland management (pasture, meadow), site conditions (area, shape, terrain attributes), and landscape variables (landscape composition, connectivity). We used ensemble of small models based on bivariate generalized linear models for explaining and predicting the butterfly occurrence pattern. Bivariate models revealed that host ant nest density, plant cover and height, local grassland management type (pasture), slope and eastness, landscape forest cover and grassland connectivity had a positive effect on the occurrence of P. nausithous (average explained deviance 20.5%). Host ant density, host plant cover, and local grassland management were the most influential factors on the ensemble predictions. The presence of P. nausithous in upland grasslands is not only determined by host resources, but also by local and landscape factors. Such factors proved to be relevant for identifying and predicting suitable grassland sites for this endangered species. Consequently, we recommend that conservation actions should include a landscape perspective to promote connectivity by facilitating coherent grazing networks enabling dispersal between semi-natural upland grasslands and thus species persistence.

Incipient sympatric speciation via host race formation in Phengaris arion (Lepidoptera: Lycaenidae)

The plausibility of sympatric speciation is still debated despite increasing evidence, such as host races in insects. This speciation process may be occurring in the case of the two phenological forms of the obligatorily myrmecophilous Phengaris arion. The main goal of our research was to study the nature and causes of difference between these forms focusing primarily on the incipient speciation via host races. Molecular analyses based on highly variable microsatellites together with Wolbachia screening, male genitalia morphometrics and host ant studies were carried out on four syntopic sample pairs. Our results show that the two phenological forms of P. arion may meet the criteria for host plant races. They coexist in sympatry in certain parts of the species range which is allowed by the adaptation to the distinct phenology of the host plants. Negative selection acts against the intermediate individuals which are on the wing in the inappropriate time frame. Thus, disruptive selection affects and produces bimodal distributions of phenotypes. However, the phenology of food plants is not entirely distinct and fluctuates year by year. Therefore, the two forms can exchange genes occasionally depending on the length of the time slot when they can meet with each other. Consequently, the reproductive isolation could not be completed and the existence of the two arion forms may represent only an incipient stage of sympatric speciation. It is also clear that Wolbachia is likely not a driver of sympatric speciation in this case.

Lepidopterological fauna of Alnus glutinosa (L.) Gaertn., forests in the Sila Massif (southern Italy) (Insecta: Lepidoptera)

In this paper we described the Lepidoptera fauna of the Calabrian black alder forests in the Sila Massif, southern Italy. We sampled eight stands for moths and four stands for diurnal Lepidoptera, at 1250-1397 meters of altitude. One UV-Led light traps per stand was turned on once per month from March to November 2017 to sample moths, one semi-quantitative transect per stand carried out once every two weeks from April to September 2017 to sample diurnal Lepidoptera. We collected 9,140 individuals belonging to 402 species, of which 117 species of diurnal Lepidoptera and 306 of nocturns Lepidoptera. Orthosia incerta (Noctuidae) andEilema lurideola (Erebidae) were the most abundant nocturns Lepidoptera species, Maniola jurtina (Nymphalidae) and Polyommatus icarus (Lycaenidae) were the most abundant diurnal species. Particularly interesting was the presence of many species of great biogeographic and/or conservation interest such as Dychagiris signifera, Acossus terebra, Plusidia cheiranthi, and Zygaena nevadensis among Heterocera, and Zerynthia cassandra, Parnassius mnemosyne, Brenthis ino and Phengaris arion among Rhopalocera. Furthermore, the finding of Eupithecia trisignaria strongly improve the importance of black alder forests for the conservation of biodiversity.

New data concerning the butterfly fauna (Lepidoptera, Papilionoidea) of Veglia – Devero Natural Park and its surroundings (northwestern Italian Alps)

Species inventories represent a key instrument by which the biodiversity of an area can be better understood and are essential in developing optimal management plans for conservation. We present an annotated checklist of the butterfly fauna (Lepidoptera, Papilionoidea) of the Special Area of Conservation Alpi Veglia – Devero – Monte Giove, in the northwestern Italian Alps. The checklist represents the result of research carried out by the authors from 2003 to 2018. We identified 107 species (36.9% of the entire Italian butterfly fauna), eight of which are reported for the first time in the study area. Four species (Erebia christi, Maculinea arion, Parnassius apollo, P. mnemosyne) represent taxa of conservation concern that are included in the European Habitats Directive 92/43/EEC. We recorded a notable percentage (12.2%) of Alpine endemic species and a high number of species of the genus Erebia (17 species, 15.9%), including two highly localized Alpine endemics: E. christi and E. flavofasciata. We report new localities for these two species, discuss in more detail 19 species of particular interest, and for all species we provide information about their distribution and conservation status in the study area.

Effects of Host Interspecific Interaction in the Maculinea-Myrmica Parasite-Host System.

A model of interspecific host competition in a system with one parasite (butterfly-Maculinea) and multiple potential hosts (ants-Myrmica) is presented. Results indicate that host interspecific competition increases the occurrence of multiple host behaviour in Maculinea natural populations but decreases the ability of the parasite populations to adapt to the most abundant host species. These qualitative predictions were compared with data on host specificity, with good agreement. Analysis of the data also indicates that Maculinea teleius and Maculinea arion respond differently to changes in relative host abundances. Maculinea teleius shows a larger fraction of sites where it displays multiple host behaviour and a larger fraction of sites where the niches of the hosts overlap. In some instances, Maculinea teleius is adapted to Myrmica hosts that are present in lower frequencies. Maculinea arion is locally more host-specific and occurs at sites where host interspecific competition is unlikely and is more frequently adapted to the most abundant host species.

Changes in butterfly species richness (Lepidoptera: Papilionoidea) over two decades in the Koroška region, Northern Slovenia

Changes in butterfly fauna in the Koroška region in northeastern Slovenia have been compared over a period of 22 years. Records from 12 sampling sites from late July 2016 are compared with the same sites from late July/early August 1994. On average, 30% of species richness was lost per site, with a maximum loss of 80% at one site with complete habitat degradation. Records from 35 sampling sites from July 2016 are presented, including records of several rare habitat specialist species, such as Lycaena dispar, Plebejus optilete, Boloria titania, and Phengaris arion, the latter being of particular importance for conservation. All in all, habitat degradation has been confirmed to be the main driver of the loss of butterfly richness in the Koroška region.

A biotrophic fungal infection of the great burnet Sanguisorba officinalis indirectly affects caterpillar performance of the endangered scarce large blue butterfly Phengaris teleius.

Interactions between ecological communities of herbivores and microbes are commonly mediated by a shared plant. A tripartite interaction between a pathogenic fungus-host plant-herbivorous insect is an example of such mutual influences. In such a system a fungal pathogen commonly has a negative influence on the morphology and biochemistry of the host plant, with consequences for insect herbivore performance. Here we studied whether the biotrophic fungus Podosphaera ferruginea, attacking the great burnet Sanguisorba officinalis, affects caterpillar performance of the endangered scarce large blue butterfly Phengaris teleius. Our results showed that the pathogenic fungus affected the number and size of inflorescences produced by food-plants and, more importantly, had indirect, plant-mediated effects on the abundance, body mass and immune response of caterpillars. Specifically, we found the relationship between caterpillar abundance and variability in inflorescence size on a plant to be positive among healthy food-plants, and negative among infected food-plants. Caterpillars that fed on healthy food-plants were smaller than those that fed on infected food-plants in one studied season, while there was no such difference in the other season. We observed the relationship between caterpillar immune response and the proportion of infected great burnets within a habitat patch to be positive when caterpillars fed on healthy food-plants, and negative when caterpillars fed on infected food-plants. Our results suggest that this biotrophic fungal infection of the great burnet may impose a significant indirect influence on P. teleius caterpillar performance with potential consequences for the population dynamics and structure of this endangered butterfly.

First Data on the Host Ant Usage of Large Blue from the Carpathian Basin

The protected Maculinea arion is an obligate myrmecophilous butterfly (Lepidoptera, Lycaenidae). Fourth instar larvae and pupae develop in Myrmica (Hymenoptera: Formicidae) ant nests. Host ant specificity varies geographically, and knowledge of the local host ant species is important to understand the biogeography and evolution of this species, and vital for its conservation. Here we report the first data on the host ant usage of M. arion in the Carpathian Basin, one prepupal caterpillar from a Myrmica specioides Bondroit, 1918 and one pupa from a M. scabrinodis Nylander, 1846 nest. Myrmica specioides is a new host ant species of M. arion. It is important to collect further data on the host ant usage of M. arion, despite the difficulties of data collection.

Relative Contribution of Matrix Structure, Patch Resources and Management to the Local Densities of Two Large Blue Butterfly Species.

The type of matrix, the landscape surrounding habitat patches, may determine the distribution and function of local populations. However, the matrix is often heterogeneous, and its various components may differentially contribute to metapopulation processes at different spatial scales, a phenomenon that has rarely been investigated. The aim of this study was to estimate the relative importance of matrix composition and spatial scale, habitat quality, and management intensity on the occurrence and density of local populations of two endangered large blue butterflies: Phengaris teleius and P. nausithous. Presence and abundance data were assessed over two years, 2011–12, in 100 local patches within two heterogeneous regions (near Kraków and Tarnów, southern Poland). The matrix composition was analyzed at eight spatial scales. We observed high occupancy rates in both species, regions and years. With the exception of area and isolation, almost all of the matrix components contributed to Phengaris sp. densities. The different matrix components acted at different spatial scales (grassland cover within 4 and 3 km, field cover within 0.4 and 0.3 km and water cover within 4 km radii for P. teleius and P. nausithous, respectively) and provided the highest independent contribution to the butterfly densities. Additionally, the effects of a 0.4 km radius of forest cover and a food plant cover on P. teleius, and a 1 km radius of settlement cover and management intensity on P. nausithous densities were observed. Contrary to former studies we conclude that the matrix heterogeneity and spatial scale rather than general matrix type are of relevance for densities of butterflies. Conservation strategies for these umbrella species should concentrate on maintaining habitat quality and managing matrix composition at the most appropriate spatial scales.

Population demography of the endangered large blue butterfly Maculinea arion in Europe

Demographic parameters such as survival, sex ratio and abundance can profoundly affect the viability of populations and thus are of primary importance in species of conservation concern. Although numerous studies have been published on certain aspects of the ecology and evolution of the endangered Large Blue butterfly Maculinea arion, there is still a lack of detailed knowledge on its populations’ demography. Moreover, M. arion populates a variety of xerothermic habitats throughout its European range using various food plants and host ants, which leads to complications in its conservation. Our aim was to estimate demographic parameters of M. arion populations in different parts of its European range. Detailed mark-recapture sampling was conducted on populations in four different countries. We often found that daily apparent survival probability declined with increasing age of individuals, but there was no difference between male and female survival. In smaller populations, the sex ratio was rather female-biased. Our most interesting result was the lack of protandry in some populations that might be a consequence of selection against reproductive asynchrony in small populations or a polyandrous mating system. The perfect coincidence of male and female phenology can positively affect the effective population size, because the lack of reproductive asynchrony increases the chance of male–female encounters. Abundance of the studied populations ranged between 100 and 1,600 individuals, smaller populations were on the verge of extinction. Habitat of the threatened small populations was either overgrazed or abandoned, while habitat of larger, stable populations was lightly grazed.

The importance of resource distribution: spatial co-occurrence of host plants and host ants coincides with increased egg densities of the Dusky Large Blue Maculinea nausithous (Lepidoptera: Lycaenidae)

The occurrence of the Dusky Large Blue Butterfly (Maculinea nausithous) critically depends on the availability of two key resources: the Great Burnet (Sanguisorba officinalis) as primary nectar source for adults, for egg laying and early larval development, and the host ant Myrmica rubra as the food of late instar larvae. Thus, their distributions are key parameters shaping habitat suitability, and we expected that overlapping of both resources would have a strong impact on the size of local M. nausithous populations. Their egg density may be affected (a) by the fraction of host plants per site located within My. rubra activity ranges at the patch scale, or (b) by the availability of host plants with host ants in close range at the local scale, due to the potential ability of butterfly females to detect their host ants. To test the above hypothesis, we recorded spatial distribution patterns of host plants and host ants on 29 study sites in south-western Germany and related them to egg density data of M. nausithous. We found a positive relationship between co-occurence of host plant and host ant and M. nausithous egg density at the patch scale, whereas no correlation was found at the local scale. Thus, focal populations are strongly limited by the abundance of host plants, covered with My. rubra activity, as ant-mediated oviposition could not be proved. Our results underline the importance of resource distribution; the understanding of its impacts may provide useful insights into how M. nausithous habitats can be managed in order increase their carrying capacity.

Living on the edge: population ecology of Phengaris teleius in Serbia

Due to their complex and interesting life cycle and alarming conservation status the Large Blue butterflies have become one of the most studied group of insects in Europe. In Serbia, however, Phengaris teleius has recently been discovered (in the far north of the country) and, since this initial finding, significant efforts have been made to map the local distribution of this species and to implement conservation measures. A mark-release-recapture study was initiated to obtain a more detailed report about population size and structure in Serbia. Results have shown that localities and patches within these localities are well connected by migration of butterflies and gave some evidence for metapopulation organisation. The total number of individuals was estimated at 15,000, which makes it one of the largest known metapopulations in Europe. Unusual for populations at the edge of the distribution range, these are characterized with large population estimates and relative stability. Compared to other areas in Europe, butterflies in Serbia start to fly 2 weeks later in the summer, probably a consequence of a late mowing regime initiated during July. Some evidence of a negative relationship between the survival of P. teleius adults and local population density was also found. With favourable management, these populations could remain stable for the foreseeable future. The preservation of large, healthy populations of P. teleius supported by a favourable management and monitoring programme along with the sustainability of individual dispersal translocation between patches should be a prime aim.