Host Ant Species Research Articles

"The Reference Genome Of The Kidnapper Ant, Polyergus Mexicanus".

Polyergus kidnapper ants are widely distributed, but relatively uncommon, throughout the Holarctic, spanning an elevational range from sea level to over 3000 m. These species are well known for their obligate social parasitism with various Formica ant species, which they kidnap in dramatic, highly coordinated raids. Kidnapped Formica larvae and pupae become integrated into the Polyergus colony where they develop into adults and perform nearly all of the necessary colony tasks for the benefit of their captors. In California, Polyergus mexicanus is the most widely distributed Polyergus, but recent evidence has identified substantial genetic polymorphism within this species, including genetically divergent lineages associated with the use of different Formica host species. Given its unique behavior and genetic diversity, Polyergus mexicanus plays a critical role in maintaining ecosystem balance by influencing the population dynamics and genetic diversity of its host ant species, Formica, highlighting its conservation value and importance in the context of biodiversity preservation. Here, we present a high-quality genome assembly of P. mexicanus from a sample collected in Plumas County, CA, USA, in the foothills of the central Sierra Nevada. This genome assembly consists of 364 scaffolds spanning 252.31Mb, with contig N50 of 481,250kb, scaffold N50 of 10.36Mb, and BUSCO completeness of 95.4%. We also assembled the genome of the Wolbachia endosymbiont of P. mexicanus - a single, circular contig spanning 1.23Mb. These genome sequences provide essential resources for future studies of conservation genetics, population genetics, speciation, and behavioral ecology in this charismatic social insect.

Enforced specificity of an animal symbiosis.

Insect diversification has been catalyzed by widespread specialization on novel hosts - a process underlying exceptional radiations of phytophagous beetles, lepidopterans, parasitoid wasps, and inordinate lineages of symbionts, predators and other trophic specialists. The strict fidelity of many such interspecies associations is posited to hinge on sensory tuning to host-derived cues, a model supported by studies of neural function in host-specific model species. Here, we investigated the sensory basis of symbiotic interactions between a myrmecophile rove beetle and its single, natural host ant species. We show that host cues trigger analogous behaviors in both ant and symbiont. Cuticular hydrocarbons - the ant's nestmate recognition pheromones - elicit partner recognition by the beetle and execution of ant grooming behavior, integrating the beetle into the colony via chemical mimicry. The beetle also follows host trail pheromones, permitting inter-colony dispersal. Remarkably, the rove beetle also performs its symbiotic behaviors with ant species separated by ~95 million years, and shows minimal preference for its natural host over non-host ants. Experimentally validated agent-based modeling supports a scenario in which specificity is enforced by physiological constraints on symbiont dispersal, and negative fitness interactions with alternative hosts, rather than via sensory tuning. Enforced specificity may be a pervasive mechanism of host range restriction of specialists embedded within host niches. Chance realization of latent compatibilities with alternative hosts may facilitate host switching, enabling deep-time persistence of obligately symbiotic lineages.

Clavigeritae (Coleoptera, Staphylinidae, Pselaphinae) of the Arabian Peninsula with the description of a new species of Corynotopsis Jeannel, 1951 from Oman.

Corynotopsisomanicussp. nov. of the myrmecophilous supertribe Clavigeritae is described from Oman. The type series was collected at night and the ant host species remains unknown. Corynotopsisscotti Jeannel, 1951 is newly recorded for Yemen, and Commatocerusconcinnus Besuchet & Cuccodoro, 2011 for Oman. Lasius Fabricius, 1804 and Lepisiota Santschi, 1926 are, for the first time, determined as hosts of the latter species. The problematic taxonomic status of Corynotopsisscotti is discussed. A distribution map of all Clavigeritae known from the Arabian Peninsula is provided.

Impact of Long-Term Floods on Spatial Dynamics of Myrmica scabrinodis, a Host Ant of a Highly Threatened Scarce Large Blue (Phengaris teleius).

Extensively used wet meadows with high species diversity are under threat in Europe by anthropogenic pressure. The increasing frequency of prolonged flooding is emerging as an additional threat to this fragile environment. In our study, we investigated how prolonged flooding affects the spatial distribution and temporal dynamics (through mortality and recolonization process) of the host ant species Myrmica scabrinodis, which is essential for the survival of the endangered Scarce large blue (Phengaris teleius). The study was conducted in the flood-prone Ljubljansko barje plain situated on the southern edge of the species' global range. Prolonged flooding in the study area, possibly affecting the past and current distribution of the host ant M. scabrinodis, was recorded in 2010, 2013, and 2017. In 2020, we set 160 ant traps to estimate the distribution of host ants in a system of meadows covering the entire gradient of flood history. Results indicate that M. scabrinodis survives the flooding for up to three days, starting to disappear if flooding persists longer. After the flooding recedes, ants gradually recolonize empty habitats from the surrounding upland refugia. Our spatial analyses predict that the average recolonization speed was about 29 m per year and that in a year, ants compensate for the mortality effects of 1.8 days of flooding by recolonization in a year. These results show that flooding should be considered as an additional (in some areas, a major) threat to the endangered P. teleius through its deleterious effects on the host ant species.

A new species of Ecitonides Wasmann, 1894 (Coleoptera: Staphylinidae: Paederinae) from Peru and phylogenetic placement of the genus based on molecular data.

Ecitonides constanceae sp. nov., a new species of the myrmecophilous genus Ecitonides Wasmann, 1894, which is associated with army ants (Hymenoptera: Formicidae: Ecitoninae), is described from Peru. The holotype, which is the only known specimen, was collected at light at Los Amigos Biological Station, Madre de Dios department, Peru. The army ant host species is unknown. The new species is distinguished from congeners and an updated key of the species, as well as a checklist of Ecitonides and their associated host ants are provided. Based on the holotype we non-destructively extracted DNA and sequenced two genes which were incorportated into an existing molecular phylogenetic dataset and analysed using Bayesian Inference. Ecitonides is recovered as sister to recently described thermitophilous genus Ruptor ya et al. 2022 and placed in the so-called Medonina and allied taxa clade. Beyond Bayesian Inference phylogenetic analysis and their associated nodal support methods, we also explored the position of the Ecitonides within the posterior sample of trees produced in the Bayesian analyses, which further supported its placement.

<i>Chrysoritis</i> Butler (Papilionoidea: Lycaenidae: Aphnaeinae) – Part I: Molecular phylogenetic analyses of a South African genus of myrmecophilous butterflies

The molecular data of Talavera et al. (2020) is re-analysed to provide a foundation for a taxonomic revision of Chrysoritis. A COI phylogeny recovers most of the Chrysoritis species as monophyletic, and a few as polyphyletic but supported by the CAD gene. In the thysbe clade, most species, despite occurring in sympatry with at least one other species in the clade, maintain distinctive wing facies and ecological identity without intermediate forms. Within the thysbe clade, which contains the majority of species, sister taxon comparisons based on the COI phylogeny suggest speciation has been predominantly allopatric and accompanied mostly by minor morphological change and sometimes also a change in male patrolling terrain and/or host ant species. The diversification of the thysbe clade and the taxonomic implications of our results are discussed.

Fungi Associated with Messor Ants on the Balkan Peninsula: First Biogeographical Data

Ant nests’ relatively stable and long-lasting microhabitats present ideal living conditions for many uni- and multicellular organisms, whose relationships range from mutualistic to parasitic. Messor harvester ants inhabit arid and semi-arid open areas where their colonies consist of large numbers of individuals. Due to the high number of other organisms associated with harvester ants, their nests can be defined as islands for unique biota. Despite significant progress in research on ant-associated fungi in Europe, little is still known about the recently described ectoparasitic fungus Rickia lenoirii Santamaria, 2015 (Laboulbeniales), found on two species of ants of the genus Messor. Here we report for the first time the occurrence of the ectoparasitic ant-associated fungus R. lenoirii from three countries (Albania, Bulgaria, and continental Greece) and multiple localities in the Balkans. The fungus was detected on four ant host species—Messor structor (Latreille, 1798), M. wasmanni Krausse, 1910, M. hellenius Agosti & Collingwood, 1987, and M. mcarthuri Steiner et al., 2018 with the latter two representing new host records. Furthermore, spores of the widespread endoparasitic fungus of ants, Myrmicinosporidium durum Hölldobler, 1933 (Blastocladiomycota), were reported for the first time in Messor structor (Bulgaria). Images of the ant-associated Rickia lenoirii taken with a scanning electron microscope, a comparison with R. wasmannii, and a distribution map are also presented.

Environments and Hosts Structure the Bacterial Microbiomes of Fungus-Gardening Ants and their Symbiotic Fungus Gardens.

The fungus gardening-ant system is considered a complex, multi-tiered symbiosis, as it is composed of ants, their fungus, and microorganisms associated with either ants or fungus. We examine the bacterial microbiome of Trachymyrmex septentrionalis and Mycetomoellerius turrifex ants and their symbiotic fungus gardens, using 16S rRNA Illumina sequencing, over a region spanning approximately 350km (east and central Texas). Typically, microorganisms can be acquired from a parent colony (vertical transmission) or from the environment (horizontal transmission). Because the symbiosis is characterized by co-dispersal of the ants and fungus, elements of both ant and fungus garden microbiome could be characterized by vertical transmission. The goals of this study were to explore how both the ant and fungus garden bacterial microbiome are acquired. The main findings were that different mechanisms appear to explain the structure the microbiomes of ants and their symbiotic fungus gardens. Ant associated microbiomes had a strong host ant signature, which could be indicative of vertical inheritance of the ant associated bacterial microbiome or an unknown mechanism of active uptake or screening. On the other hand, the bacterial microbiome of the fungus garden was more complex in that some bacterial taxa appear to be structured by the ant host species, whereas others by fungal lineage or the environment (geographic region). Thus bacteria in fungus gardens appear to be acquired both horizontally and vertically.

Assessing Biosynthetic Gene Cluster Diversity of Specialized Metabolites in the Conserved Gut Symbionts of Herbivorous Turtle Ants.

Cephalotes are herbivorous ants (>115 species) feeding on low-nitrogen food sources, and they rely on gut symbionts to supplement their diet by recycling nitrogen food waste into amino acids. These conserved gut symbionts, which encompass five bacterial orders, have been studied previously for their primary nitrogen metabolism; however, little is known about their ability to biosynthesize specialized metabolites which can play a role in bacterial interactions between communities living in close proximity in the gut. To evaluate the biosynthetic potential of their gut symbionts, we mine 14 cultured isolate genomes and gut metagenomes across 17 Cephalotes species to explore the biodiversity of biosynthetic gene clusters (BGCs) producing specialized metabolites. The diversity of BGCs across Cephalotes phylogeny was analyzed using sequence similarity networking and BGC phylogenetic reconstruction. Our results reveal that the conserved gut symbionts involved in the nutritional symbiosis possess 80% of all the 233 BGCs retrieved in this work. Furthermore, the phylogenetic analysis of BGCs reveals different patterns of distribution, suggesting different mechanisms of conservation. A siderophore BGC shows high similarity in a single symbiont across different ant host species, whereas a BGC encoding the production of non-ribosomal peptides (NRPs) found different symbionts within a single host species. Additionally, BGCs were abundant in four of the five bacterial orders of conserved symbionts co-occurring in the hindgut. However, one major symbiont localized alone in the midgut lack BGCs. Because the spatial isolation prevents direct interaction with other symbionts, this result supports the idea that BGCs are maintained in bacteria living in close proximity but are dispensable for an alone-living symbiont. These findings together pave the way for studying the mechanisms of BGC conservation and evolution in gut bacterial genomes associated with Cephalotes. This work also provides a genetic background for further study, aiming to characterize bacterial specialized metabolites and to understand their functional role in multipartite mutualisms between conserved gut symbionts and Cephalotes turtle ants.

Disease management in two sympatric Apterostigma fungus-growing ants for controlling the parasitic fungus Escovopsis.

Antagonistic interactions between host and parasites are often embedded in networks of interacting species, in which hosts may be attacked by competing parasites species, and parasites may infect more than one host species. To better understand the evolution of host defenses and parasite counterdefenses in the context of a multihost, multiparasite system, we studied two sympatric species, of congeneric fungus‐growing ants (Attini) species and their symbiotic fungal cultivars, which are attacked by multiple morphotypes of parasitic fungi in the genus, Escovopsis. To assess whether closely related ant species and their cultured fungi are evolving defenses against the same or different parasitic strains, we characterized Escovopsis that were isolated from colonies of sympatric Apterostigma dentigerum and A. pilosum. We assessed in vitro and in vivo interactions of these parasites with their hosts. While the ant cultivars are parasitized by similar Escovopsis spp., the frequency of infection by these pathogens differs between the two ant species. The ability of the host fungi to suppress Escovopsis growth, as well as ant defensive responses toward the parasites, differs depending on the parasite strain and on the host ant species.

Host Ant Change of a Socially Parasitic Butterfly (Phengaris alcon) through Host Nest Take-Over.

Simple SummaryThe endangered Alcon blue butterfly (Phengaris alcon) starts its larval stage by feeding on the seeds of gentian plants, after which it completes development in the nests of suitable Myrmica ant species. Any particular population often uses more than one host ant species, and some host switching is likely. To test switching in the lab we introduced relatively strong colonies of alien Myrmica species to the arenas of weaker colonies, and to orphaned caterpillars. Most of the caterpillars were successfully readopted by alien ants, and survived well. Our results suggest higher ecological plasticity in host ant usage of this butterfly than generally thought. The Alcon blue is an iconic species, e.g., its special life cycle has featured in several high profile television and streaming media wildlife series, and the more we know about its unusual life the more we can do for its protected sites.The socially parasitic Alcon blue butterfly (Phengaris alcon) starts its larval stage by feeding on the seeds of gentians, after which it completes development in the nests of suitable Myrmica ant species. The host plant and host ant species can differ at the population level within a region, and local adaptation is common, but some host switches are observed. It has been suggested that one mechanism of change is through the re-adoption of caterpillars by different ant species, either through occupation of abandoned nests or take-over of established nests by competitively superior colonies. To test this question in the lab we introduced relatively strong colonies (50 workers) of alien Myrmica species to the arenas of weaker colonies (two caterpillars with six workers), and to orphaned caterpillars (two caterpillars without ants). We used caterpillars from a xerophylic population of P. alcon, and both local hosts, M. sabuleti and M. scabrinodis, testing the possibility of host switch between these two host ant species during larval development. Most of the caterpillars were successfully readopted by alien ants, and survived well. Our results suggest higher ecological plasticity in host ant usage of this butterfly than generally thought.

The ant cricket Myrmecophilus orientalis on the Dodecanese Islands, Greece (Orthoptera: Myrmecophilidae)

This study reports the occurrence of the ant cricket Myrmecophilus orientalis Stalling, 2010 on the Dodecanese Islands Kos and Tilos, Greece. This is the first evidence of M. orientalis from Greece and Europe. The species lives in ant nests under stones and in dead wood in open scrubland and pine forests. The adults were found in the nests of large Camponotus species, while the juveniles were found in the nests of small ant species of the genera Crematogaster and Lepisiota. We assumed that the species changes the host ant species during its life cycle.

Evaluating the tradeoffs of a generalist parasitoid fungus, Ophiocordyceps unilateralis, on different sympatric ant hosts

It is essential for the survival and reproduction of parasitoids to adapt to the fluctuating host resources. Phenotypic plasticity may enable a parasitoid species to successfully achieve its control over a range of host species to maximize fitness in different hosts that may each require dissimilar, possibly conflicting, specific adaptations. However, there is limited information on how the fitness effects of host switching partition into costs due to the novelty of host species, where unfamiliarity with host physiological and morphological changes and its anti-parasite defenses reduces parasitoid growth, survivorship and/or reproductive success. In this study, the parasitoid fungus Ophiocordyceps unilateralis sensu lato was found to sympatrically infect a principal host ant species and other alternative sympatric hosts in the forest of central Taiwan. We herein report that the occurrence of ant infections by O. unilateralis s.l. shows spatial and temporal variation patterns on different host species. Results showed that the height from the ground to the leaf where the infected ants grip on, perithecia-forming ability, and growth rate of the stroma of the parasitoid fungus were dissimilar on different host species. These host range expansions not only related the fitness of O. unilateralis s.l. but also influenced the expression of extended phenotypic traits. Our findings revealed that a generalist parasitoid fungus suffered an evolutionary tradeoff between host breadth expansion and host-use efficiency.

Comparative analyses of caste, sex, and developmental stage-specific transcriptomes in two Temnothorax ants.

Social insects dominate arthropod communities worldwide due to cooperation and division of labor in their societies. This, however, makes them vulnerable to exploitation by social parasites, such as slave‐making ants. Slave‐making ant workers pillage brood from neighboring nests of related host ant species. After emergence, host workers take over all nonreproductive colony tasks, whereas slavemakers have lost the ability to care for themselves and their offspring. Here, we compared transcriptomes of different developmental stages (larvae, pupae, and adults), castes (queens and workers), and sexes of two related ant species, the slavemaker Temnothorax americanus and its host Temnothorax longispinosus. Our aim was to investigate commonalities and differences in group‐specific transcriptomes, whereupon across‐species differences possibly can be explained by their divergent lifestyles. Larvae and pupae showed the highest similarity between the two species and upregulated genes with enriched functions of translation and chitin metabolism, respectively. Workers commonly upregulated oxidation‐reduction genes, possibly indicative of their active lifestyle. Host workers, but not workers of the slavemaker, upregulated a “social behavior” gene. In slavemaker queens and workers, genes associated with the regulation of transposable elements were upregulated. Queens of both species showed transcriptomic signals of anti‐aging mechanisms, with hosts upregulating various DNA repair pathways and slavemaker queens investing in trehalose metabolism. The transcriptomes of males showed enriched functions for quite general terms realized in different genes and pathways in each species. In summary, the strong interspecific commonalities in larvae, pupae, and workers were reflected in the same enriched Gene Ontology (GO) terms. Less commonalities occurred in the transcriptomes of queens and males, which apparently utilize different pathways to achieve a long life and sperm production, respectively. We found that all analyzed groups in this study show characteristic GO terms, with similar patterns in both species.

Disentangling the assembly mechanisms of ant cuticular bacterial communities of two Amazonian ant species sharing a common arboreal nest.

Bacteria living on the cuticle of ants are generally studied for their protective role against pathogens, especially in the clade of fungus-growing ants. However, little is known regarding the diversity of cuticular bacteria in other ant host species, as well as the mechanisms leading to the composition of these communities. Here, we used 16S rRNA gene amplicon sequencing to study the influence of host species, species interactions and the pool of bacteria from the environment on the assembly of cuticular bacterial communities on two phylogenetically distant Amazonian ant species that frequently nest together inside the roots system of epiphytic plants, Camponotus femoratus and Crematogaster levior. Our results show that (a) the vast majority of the bacterial community on the cuticle is shared with the nest, suggesting that most bacteria on the cuticle are acquired through environmental acquisition, (b) 5.2% and 2.0% of operational taxonomic units (OTUs) are respectively specific to Ca.femoratus and Cr.levior, probably representing their respective core cuticular bacterial community, and (c) 3.6% of OTUs are shared between the two ant species. Additionally, mass spectrometry metabolomics analysis of metabolites on the cuticle of ants, which excludes the detection of cuticular hydrocarbons produced by the host, were conducted to evaluate correlations among bacterial OTUs and m/z ion mass. Although some positive and negative correlations are found, the cuticular chemical composition was weakly species-specific, suggesting that cuticular bacterial communities are prominently environmentally acquired. Overall, our results suggest the environment is the dominant source of bacteria found on the cuticle of ants.

Interspecific Eavesdropping on Ant Chemical Communication

Chemical communication is a fundamental, highly complex component of social insect societies. Ants in particular employ a remarkable diversity of chemical signals to maintain social cohesion among nestmates, gain essential resources through coordinated foraging, and warn of danger. Although the chemicals used can be functionally specific, they are vulnerable to exploitation by eavesdropping natural enemies (e.g., parasitoids, predators, parasites) and other associates (e.g., myrmecophiles). Ant nests are nutrient hotspots due to their collection of resources warranting keen defense systems; yet the heavily-defended hideouts are frequently invaded. Many organisms exploit ant species, but how they locate hosts—including what host-derived cues are used—is still poorly understood. Here, we review current knowledge about how ant chemical communication systems can be exploited by unintended receivers. We take a case study approach and illustrate the diversity of ant associates and host traits that may predispose ants to exploitation. We identify knowledge gaps by reviewing host systems and listing: 1) the types of associates (e.g., fly, wasp, beetle) where eavesdropping is likely occurring, organized by the host communication system that is being exploited; 2) the ant parasites that exploit trail pheromones; and 3) the experimentally-determined chemicals (i.e., alarm/defensive pheromones), used by eavesdroppers. At least 25 families of arthropods (10 orders) potentially eavesdrop on ant communication systems and nearly 20 host ant species are vulnerable to trail parasite ant species. We also propose future research that will improve our understanding of community assembly by examining host traits (e.g., latitude, nest characteristics, trail system) that influence their susceptibility to eavesdropping associates.

Genomics of extreme ecological specialists: multiple convergent evolution but no genetic divergence between ecotypes of Maculinea alcon butterflies

Biotic interactions are often acknowledged as catalysers of genetic divergence and eventual explanation of processes driving species richness. We address the question, whether extreme ecological specialization is always associated with lineage sorting, by analysing polymorphisms in morphologically similar ecotypes of the myrmecophilous butterfly Maculinea alcon. The ecotypes occur in either hygric or xeric habitats, use different larval host plants and ant species, but no significant distinctive molecular traits have been revealed so far. We apply genome-wide RAD-sequencing to specimens originating from both habitats across Europe in order to get a view of the potential evolutionary processes at work. Our results confirm that genetic variation is mainly structured geographically but not ecologically — specimens from close localities are more related to each other than populations of each ecotype from distant localities. However, we found two loci for which the association with xeric versus hygric habitats is supported by segregating alleles, suggesting convergent evolution of habitat preference. Thus, ecological divergence between the forms probably does not represent an early stage of speciation, but may result from independent recurring adaptations involving few genes. We discuss the implications of these results for conservation and suggest preserving biotic interactions and main genetic clusters.

Morphological characteristics reflect food sources and degree of host ant specificity in four Myrmecophilus crickets

Myrmecophilus crickets are well-known inquilines that live and obtain food resources in ant nests. In Japanese Myrmecophilus species various degrees of host specificity are reflected in behavioral differences among species. For example, extremely specialized species perform trophallaxis with their host ant species, whereas generalist species may steal food from their hosts without any intimate contact. We examined behavioral variations among four Myrmecophilus species that use different hosts and show different degrees of specificity, and we also compared morphological traits such as mandible shape and hind leg length among the species. The morphometric analyses showed that an extreme host-specialist species had less complex and largely non-functional mandibles, reflecting its dependence on trophallaxis with its host ant species. In contrast, extreme host-generalist and/or moderate specialist species, which directly eat solid foods, had more complex and functional mandibles which they use to cut and crush their foods, such as insect carcasses and ant larvae. The extreme host-specialist species had shorter hind legs than the extreme host-generalist. This may reflect that it suffers few attacks from the host ants. Our results show that in Myrmecophilus food sources shape behavioral interactions with host ant species and correlate with morphological characteristics.

Spatial and temporal variation in host–parasitoid interactions: leafcutter ant hosts and their phorid parasitoids

1. Parasitoid–host interactions are important components of ecological communities. Although parasitoid–host interactions are strongly shaped by evolutionary history, the abundance of both the parasitoid and the host may have a role in determining the nature of the interaction once phylogenetic relationships are considered.2. Leafcutter ants are hosts of phorid parasitoids and represent a well‐defined and specialised module within a larger network of ant–symbiont interactions. A low specificity host taxa and a positive association between host abundance and parasitoid interaction frequency were expected due to the close phylogenetic relatedness of the hosts.3. The interactions among all species of leafcutter ants and their parasitoids were quantified in two localities with different species richness. This study also characterised the spatial‐temporal variability of these interactions, determined the patterns of parasitoid specificity and host selection, and tested for an association between host abundance and parasitoid interaction frequency.4. Contrary to expectation, most parasitoid species were highly specialised and interaction frequency for parasitoid species was not related to host abundance. All host ant species were attacked by more than one phorid species. Some phorid species used more than one host species and showed preference for the same species over space and time, suggesting that there are physiological and/or behavioural restrictions on host use.5. These results show that there is a tendency for specialisation even when hosts are highly similar in their ecology. From a biological control perspective, these parasitoids may be effective candidates, due to the high specificity of some species and little host‐use variation through time.

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.