Formica Rufa Research Articles

Differences Between the Allometric Rules Governing Two Formica lugubris Zetterstedt, 1838 (Hymenoptera: Formicidae) Ants Populations in Northern Greece

Red wood ant workers, despite being monomorphic, show a wide range in their body size even within the same colony. As overall size grows, some organs grow in a negative allometric relationship with the body. Genetic and environmental factors, like diet and temperature, are considered as key factors that determine differences in body and organ growth. We studied the allometric rules governing the organs in two different populations of red wood ants in two different environments in Northern Greece to identify similarities and differences. These rules, although linear for both populations and negative allometric for most of the traits measured, differ in the two study areas, while the shape of the head found to be governed by different allometric rules between the two populations. The whole shape and size of red wood ants varies greatly even within the same species and we cannot create allometric models for two different areas, even when they belong in the same species. The differences might be a result of differences in the genome and the environmental conditions between the two populations.

Evaluation of the Anticancer and Probiotic Potential of Autochthonous (Wild) Lacticaseibacillus paracasei Strains from New Ecological Niches as a Possible Additive for Functional Dairy Foods.

Probiotics such as Lactobacillus spp. could modulate the intestinal microbiota composition, supporting gastrointestinal tract barrier function and benefiting human health. To evaluate the anticancer and probiotic properties of potentially active autochthonous Lacticaseibacillus paracasei strains on proliferating and differentiated enterocytes, human colon adenocarcinoma cell line HT29 was used as a model. The lactic acid bacteria (LAB) were isolated from new ecological niches-mountain anthills populated by redwood ants (Formica rufa L.). Human colorectal adenocarcinoma cells (HT29, ATCC, HTB-38™) were treated for twenty-four hours with supernatants (SNs) derived from four strains of Lacticaseibacillus paracasei: P4, C8, C15 and M2.1. An MTT assay, alkaline phosphatase activity, IAP, Bax and Bcl-2 gene expression analysis (RT-qPCR) and the Bax/Bcl-2 ratio were evaluated. The MTT assay revealed that the observed effects varied among groups. However, 10% neutralized supernatants from P4, C8, C15 and M2.1 strains did not show cytotoxic effects. In contrast to non-differentiated cells, a significant (p < 0.001) rise in ALP activity in all treatments, with an average of 18%, was established in differentiated cells. The IAP expression was remarkably downregulated in the differentiated M2.1 group (p < 0.05) and upregulated in the non-differentiated P4 (p < 0.05) and M2.1 (p < 0.05) groups. The Bax/Bcl-2 quantity expression ratio in P4 was significantly (p < 0.05) upregulated in proliferating cancer cells, but in P4- and M2.1-differentiated cells these values were downregulated (p < 0.05). The obtained results indicate that the isolated L. paracasei strains possess anticancer and probiotic properties and could be used as additives for functional dairy foods and thus benefit human health.

Changes in the Structure of Nest Complexes of the Red Wood Ants Formica rufa and F. polyctena (Hymenoptera, Formicidae) in Urban Forests

The aim of this work is to evaluate changes in the structure of nest complexes of two species of red wood ants: Formica rufa Linnaeus, 1761 and F. polyctena Foerster, 1850, in the city of Kyiv (Ukraine) using morpho[1]metric indicators, as well as to evaluate their dynamics. In 2014–2022, nest complexes of two species of red wood ants (Formica rufa, F. polyctena) were observed in urbanised forests within the city of Kyiv. A total of 472 F. rufa and 411 F. polyctena nests were studied in 7 nest complexes (4 — F. polyctena, 3 — F. rufa). The total volume of F. polyctena nests were found to decrease by 2020–2021, while the volume of F. rufa nests remained at the same level or even increased. This suggests that F. rufa is more resistant to changes in forestry conditions.

Efficacy of homoeopathic medicine Formica Rufa 30ch in the management of osteoarthritis of knee joint using womac index score method

Osteoarthritis is a chronic degenerative disorder of multifactorial etiology characterized by the loss of articular cartilage, hypertrophy of bone at the margins, subchondral sclerosis and range of biochemical and morphological alterations of the synovial membrane and joint capsule.Homoeopathic philosophy does not favour the use of temporary pain killers or short cuts in treating diseases. Homoeopathy treats the patients as a whole by considering the symptoms. There are several Medicines found to be effective in the management of Osteoarthritis. This is an attempt to evaluate the efficacy of Homoeopathic Medicine Formica Rufa 30CH in the treatment of Osteoarthritis of Knee Joint. Hence I selected this homoeopathic medicine Formica Rufa.

Comparative Analysis of Facial Coloration between Introduced and Source Populations of the Red Wood Ant Formica paralugubris.

The variation in the typical black-reddish color of red wood ants (Formica rufa group) has been recently suggested as a good indicator of habitat quality, being dependent on environmental conditions. However, the relative contribution of external factors and heritability in shaping this trait is poorly investigated. In this study, we compared the facial coloration of workers from four introduced populations of Formica paralugubris with those of the two Alpine populations from which they had been taken. We used a Relative Warp Analysis to describe the variations in the shape of this trait. We expected each introduced population to be more similar to its population of origin if the color pattern was predominantly genetically determined. On the contrary, due to the considerable differences in habitat type and climate between the Alps and the Apennines, we expected to observe differences between the introduced population and their origin population if the coloration was mostly environmentally determined. With one exception that we discuss, the results showed that ants from the two source populations had different phenotypes, and that the introduced populations had a shape similar to the population of origin, suggesting a stable genetic background. Surprisingly, the habitat type seems to have a less clear effect, even if within-population differences suggest the influence of very localized environmental factors. Finally, we found that the facial coloration shape is affected by the ant’s size, a result in line with previous studies.

The Effect of the Introduced Red Wood Ant Formica paralugubris on the Frequency of Ant Nests and First Plesiobiotic Association between Myrmica ruginodis (Nylander, 1846) and Lasius flavus (Fabricius, 1782)

Red wood ants are ecologically dominant species that affect the composition of the invertebrate community. In the past century, one of these species, Formica paralugubris (Seifert 1996), was introduced outside its native area (the Alps), in the Apennines (Italy). Here we investigated the effect of the presence of an introduced population of F. paralugubris on the frequency of nests of other ant species in Abetone, Central Apennines. Ant nests were found only in the area unoccupied by F. paralugubris. In this area, we also found one pleometrotic association between queens of Lasius flavus (Fabricius, 1782) and two plesiobiotic associations, one between Formica fusca (Linnaeus, 1758) and L. flavus and the other one between Myrmica ruginodis (Nylander, 1846) and L. flavus. This latter is the first plesiobiotic relationship reported between these two species, the second reported for M. ruginodis and the 10th for L. flavus. Additionally, this is the first plesiobiotic association reported for the Mediterranean region and Southern Europe.

The Effect of the Introduced Red Wood Ant Formica paralugubris on the Frequency of Ant Nests and First Plesiobiotic Association between Myrmica ruginodis (Nylander, 1846) and Lasius flavus (Fabricius, 1782)

Red wood ants are ecologically dominant species that affect the composition of the invertebrate community. In the past century, one of these species, Formica paralugubris (Seifert 1996), was introduced outside its native area (the Alps), in the Apennines (Italy). Here we investigated the effect of the presence of an introduced population of F. paralugubris on the frequency of nests of other ant species in Abetone, Central Apennines. Ant nests were found only in the area unoccupied by F. paralugubris. In this area, we also found one pleometrotic association between queens of Lasius flavus (Fabricius, 1782) and two plesiobiotic associations, one between Formica fusca (Linnaeus, 1758) and L. flavus and the other one between Myrmica ruginodis (Nylander, 1846) and L. flavus. This latter is the first plesiobiotic relationship reported between these two species, the second reported for M. ruginodis and the 10th for L. flavus. Additionally, this is the first plesiobiotic association reported for the Mediterranean region and Southern Europe.

Assessing Molecular Diversity in Native and Introduced Populations of Red Wood Ant Formica paralugubris.

The Formica rufa group comprises several ant species which are collectively referred to as "red wood ants" and play key roles in boreal forest ecosystems, where they are ecologically dominant and greatly influence habitat dynamics. Owing to their intense predatory activity, some of these species are used as biocontrol agents against several forest insect pests and for this aim in Italy, nearly 6000 ant nests were introduced from their native areas in the Alps to several Appeninic sites during the last century. In this work, we assessed and compared the genetic variability and structure of native and introduced populations of F. paralugubris, thus evaluating the extent of genetic drift that may have occurred since the time of introduction, using amplified fragment length polymorphism (AFLP) markers. PCR amplification with a fam_EcoRI-TAC/MseI-ATG primers combination produced a total of 147 scorable bands, with 17 identified as outlier loci. The genetic variation was higher in the introduced population compared to the native ones that, on the other hand, showed a higher diversity between nests. AMOVA results clearly pointed out that the overall genetic structure was dominated by among-worker variation, considering all populations, the Alpine vs. Apennine groups and the comparison among native and related introduced populations (all ranging between 77.84% and 79.84%). Genetic analyses unveiled the existence of six main different groups that do not entirely mirror their geographic subdivision, pointing towards a wide admixture between populations, but, at the same time, rapid diversification of some Apennine populations. Future studies based on high-throughput genomic methods are needed to obtain a thorough understanding of the effects of environmental pressure on the genetic structure and mating system of these populations.

Comparison of Geogases in Two Cenozoic Sedimentary Basins

We investigated fault gases (helium, radon, CO2) in two seismically active Cenozoic sedimentary basins: (a) Meinweg (in 2015), at a tectonically quiescent horst structure in the Lower Rhine Embayment; and (b) Bodanrück (in 2012; Lake of Constance), in the Molasse Basin and part of the seismically active Freiburg–Bonndorf–Bodensee Fault Zone (FBBFZ). Both study areas were selected because recent “GeoBio-Interactions” findings showed that red wood ants (RWA) are biological indicators of otherwise undetected degassing systems. We combined presence/absence data of RWA nests, their spatial pattern analysis (prototype lines), seismicity and known tectonic settings with soil gas analyses (a total of 817 samples) to unveil geochemical anomalies related to tectonic developments unknown so far. Currently, Meinweg can be considered “no ants land” due to the very low background-level of geogas concentrations. Thus, anomalies (Rn-CO2) weakly trending in NE-SW extension direction emerged. This could probably indicate the onset of (re)activation of the NE-SW-trending (Variscan) structures or the development of new fractures as an aftershock process of the 1992 Roermond earthquake that occurred about 15 km to the west. Results at Bodanrück (three RWA clusters and two RWA-free corridors) revealed degassing patterns in NW-SE and NNE-SSW directions in the clusters corresponding to re-activated and recent strike-slip fault systems. No gas anomalies were found in RWA-free corridors. The RWA nest distribution was shown to be a valuable tool for identifying areas of even actively degassing spotty anomalies caused by macro- and microscale brittle deformation masked by sediment cover.

Dissecting the costs of a facultative symbiosis in an isopod living with ants.

The balance between costs and benefits is expected to drive associations between species. While these balances are well understood for strict associations, we have no insights to which extent they determine facultative associations between species. Here, we quantified the costs of living in a facultative association, by studying the effects of red wood ants on the facultatively associated isopod Porcellio scaber. Porcellio scaber frequently occurred in and near hostile red wood ant nests and might outnumber obligate nest associates. The facultative association involved different costs for the isopod. We found that the density of the isopod decreases near the nest with higher ant traffic. Individuals in and near the nest were smaller than individuals further away from the nest. Smaller individuals were also found at sites with higher ant traffic. A higher proportion of wounded individuals was found closer to the nest and with higher ant traffic. We recorded pregnant females and juveniles in the nest suggesting that the life cycle can be completed inside the nests. Lab experiments showed that females died sooner and invested less in reproduction in presence of red wood ants. Porcellio scaber rarely provoked an aggression response, but large numbers were carried as prey to the nest. These preyed isopods were mainly dried out corpses. Our results showed that the ant association incurred several costs for a facultative associate. Consequently, red wood ant nests and their surrounding territory act as an alternative habitat where demographic costs are offset by a stable resource provisioning and protection.

Assembly of a Hybrid Formica aquilonia × F. polyctena Ant Genome From a Haploid Male.

Formica red wood ants are a keystone species of boreal forest ecosystems and an emerging model system in the study of speciation and hybridization. Here, we performed a standard DNA extraction from a single, field-collected Formica aquilonia × Formica polyctena haploid male and assembled its genome using ~60× of PacBio long reads. After polishing and contaminant removal, the final assembly was 272 Mb (4687 contigs, N50 = 1.16 Mb). Our reference genome contains 98.5% of the core Hymenopteran BUSCOs and was pseudo-scaffolded using the assembly of a related species, F. selysi (28 scaffolds, N50 = 8.49 Mb). Around one-third of the genome consists of repeats, and 17 426 gene models were annotated using both protein and RNAseq data (97.4% BUSCO completeness). This resource is of comparable quality to the few other single individual insect genomes assembled to date and paves the way to genomic studies of admixture in natural populations and comparative genomic approaches in Formica wood ants.

Transfer of elements into boreal forest ants at a former uranium mining site

Ants can influence ecological processes, such as the transfer of elements or radionuclides, in several ways. For example, they redistribute materials while foraging and maintaining their nests and have an important role in terrestrial food webs. Quantitative data of the transfer of elements into ants is needed, e.g., for developing improved radioecological models. In this study, samples of red wood ants (genus Formica), nest material, litter and soil were collected from a former uranium mining site in Eastern Finland. Concentrations of 33 elements were analyzed by Inductively Coupled Plasma-Mass Spectroscopy/Optical Emission Spectroscopy. Estimated element concentrations in spruce needles were used as a proxy for studying the transfer of elements into ants via aphids because spruces host the most important aphid farms in boreal forests. Empirically determined organism/medium concentration ratios (CRs) are commonly used in radioecological models. Ant/soil CRs were calculated and the validity of the fundamental assumption behind the of use of CRs (linear transfer) was evaluated. Elements that accumulated in ants in comparison to other compartments were cadmium, potassium, phosphorus, sulfur, and zinc. Ant uranium concentrations were low in comparison to soil, litter, or nest material but slightly elevated in comparison to spruce needles. Ant element concentrations were quite constant regardless of the soil concentrations. Non-linear transfer models could therefore describe the soil-to-ant transfer better than conventional CRs.

Flow-on effects of an introduced tree species: Lodgepole pine plantation affects function and performance of boreal ants

Increased demand on forests to produce renewable biomass have accelerated the use of non-native tree species in forestry worldwide, often with negative effects on native biodiversity. In Sweden, the North American lodgepole pine (Pinus contorta Douglas ex. Loudon var. latifolia) was introduced already in the 1970’s. Even though the species now covers large areas, effects on native flora and fauna have not been thoroughly evaluated. In this study, we used a large-scale field experiment with 30 paired P. contorta and P. sylvestris stands in central and northern Sweden to study the effects of P. contorta plantation on the abundance and activity of red wood ants of the Formica rufa-group, density and species richness of other ant species, as well as possible effects on the abundance of the specialized ant predator Pella humeralis. We collected epigaeic insects with pit fall traps, surveyed wood ant mound density and volume, and monitored ant activity on trees in all stands. Our analyses revealed a trend with higher mound density in P. sylvestris compared with P. contorta stands, although wood ant worker catch did not differ between the pine species. However, red wood ant activity was significantly higher in P. sylvestris stands, suggesting that P. contorta is not a preferred tree species for the tending of aphids for honeydew. Total ant species richness as well as the catch of Camponotus herculeanus and Myrmica ruginodis were higher in P. sylvestris stands, suggesting that they constitute a more favorable habitat for ants. Ant species richness was negatively influenced by wood ants in P. sylvestris stands only. A similar pattern was shown for C. herculeanus. Myrmica ruginodis was more abundant in P. sylvestris stands only if no thinning had been applied. Wood ant catch was positively correlated with catch of the specialized predatory rove beetle Pella humeralis showing that there is a strong interaction between the predatory beetle and wood ants.Our results suggest that P. contorta plantations impact both red wood ants and associated species and although competition from wood ants is more pronounced in P. sylvestris stands they still constitute a more favorable habitat for most ant species. Thus, large scale plantation of the non-native but closely related P. contorta may negatively impact epigaeic assemblages, a pattern that is not compensated by released competition by dominant red wood ants.

The Skeletomuscular System of the Mesosoma ofFormica rufaWorkers (Hymenoptera: Formicidae)

AbstractThe mesosoma is the power core of the ant, containing critical structural and muscular elements for the movement of the head, legs, and metasoma. It has been hypothesized that adaptation to ground locomotion and the loss of flight led to the substantial rearrangements in the mesosoma in worker ants and that it is likely the ant mesosoma has undergone functional modifications as ants diversified into different ecological and behavioral niches. Despite this importance, studies on the anatomy of the ant mesosoma are still scarce, and there is limited understanding of important variation of internal structures across the ant phylogeny. Recent advances in imaging techniques have made it possible to digitally dissect small insects, to document the anatomy efficiently and in detail, and to visualize these data in 3D. Here we document the mesosomal skeletomuscular system of workers of the red wood ant, Formica rufa Linnaeus, 1761, and use it to establish a 3D atlas of mesosomal anatomy that will serve as reference work for further studies. We discuss and illustrate the configuration of the skeletomuscular components and the function of the muscles in interaction with the skeletal elements. This anatomical evaluation of a ‘generalized’ ant provides a template for future studies of the mesosoma across the radiation of Formicidae, with the ultimate objective of synthesizing structural, functional, and transformational information to understand the evolution of a crucial body region of ants.

Red wood ants shape epiphytic lichen assemblages in montane silver fir forests

The Formica rufa group comprises several ant species which are collectively referred to as “red wood ants” (hereafter RWA). These species have key roles in forest ecosystems, where they are ecologically dominant and greatly influence the dynamics of the habitat they colonise. Various studies have shown how their trophic activity may affect other organisms, which include both other invertebrates and plants. We can therefore hypothesize that their presence could affect the taxonomic and functional composition of epiphytes, despite clear information on such an effect is lacking. This study aimed to fill this research gap by evaluating whether the presence of red wood ants could affect the structure and composition of lichen communities. We selected two sites on the Apennine Mountains in Italy, where the red wood ant F. paralugubris was introduced from the Alps more than 50 years ago. In each site, lichen assemblages on Abies alba trees located within the colonised areas were compared to those from nearby, non-occupied areas. The results allowed for the identification of significant effects of F. paralugubris on the structure of lichen communities. Although there was no detectable impact on lichen species richness, a significant difference in their community composition between colonised and control sites was detected. Furthermore, ant presence seemed to be associated with specific lichen functional traits such as asexual reproduction. We argue that RWA could affect the lichen community either directly, e.g., by actively dispersing the species capable of asexual reproduction through their movements on trees (ant-mediated dispersion), or indirectly through herbivore exclusion. Finally, we also observed differences in β-diversity among the colonised and non-colonised sites.

Intraspecific Relationships and Nest Mound Shape Are Affected by Habitat Features in Introduced Populations of the Red Wood Ant Formica paralugubris.

Simple SummaryRed wood ants (Formica rufa goup) are dominant ant species widespread in the Eurasian continent. These species have a strong ecological impact on the habitats they dwell in, being top-ranked predators. One of the most striking features of these ants is represented by the large nest mounds they build. In this study, we investigated how nest mound shape and colony organization of imported populations of Formica paralugubris varied in three different habitat types. We found that nest mounds differed in size, number and shape in the three habitats. In all the three sites, nests were connected by trails of workers, but the size of these nest-networks differed. We also investigated the pattern of intraspecific aggression among ants from different nests, and we showed that aggressiveness was higher within each population than between separate populations, a finding in line with a ‘nasty neighbor’ behavior.Ants belonging to the Formica rufa group build large nest mounds, which aid their survival during severe winters. We investigated whether different environmental features of the habitats affected the nest mound shape and the population structure. We assessed the shape of all the nest mounds and mapped inter-nest trails connecting mounds for three imported populations of Formica paralugubris in three forest habitats: fir-dominated, beech-dominated, and a mixture of fir and beech. Single-nest mounds were averagely smaller and flatter in the beech-dominated forest, probably because of lighter building materials. Nonetheless, by summing the volumes of all interconnected nests, the size was similar among all three sites. In fir- and beech-dominated forests, large nests were also central in the networks, suggesting a central place foraging model with these nests as reference. We finally performed aggression tests, and found that aggressiveness was significantly higher among nests belonging to the same population than between populations. The results highlight the plasticity of the species to adapt nest and colony structure to different environments. Additionally, it appears that none of these populations is unicolonial, as observed in various alpine sites, there and the observed patterns of aggression are coherent with the ‘nasty neighbor’ effect.

Biogeography and habitat preferences of red wood ants of the Formica rufa group (Hymenoptera: Formicidae) in Finland, based on citizen science data

Red wood ants (RWA) of the Formica rufa group are ecosystem engineers and important species in boreal and temperate forests. However, the permanent and temporal loss of forest habitats is a serious threat to their existence and is likely to increase with climate change. Due to the current threat of losing species, quick actions are needed. Reported here is the biogeography, relative abundance and habitat preferences of five species of RWA in Finland based on citizen science data. Species that occur in the lowlands of the Alps also occur throughout the southern parts of Finland. Only two of the five species, F. aquilonia Yarrow, 1955 and F. lugubris Zetterstedt, 1838, were common throughout the country, including northern Lapland. As their name suggests, RWAs occur mostly in forests and forest edges, but they also sometimes inhabit open or semi-open yards, mires and meadows. The most forest-specialist species is F. aquilonia and the least F. rufa Linnaeus, 1761. Surprisingly, the meadow wood ant F. pratensis Retzius, 1783 is the second most forest dwelling species, however, its preference for forest edges is clearly higher than for forest interiors. Based on current data, F. rufa may be the most tolerant of living close to buildings as its relative abundance in yards was much higher than that of the other species. The data obtained on distributions and relative abundances could be compared in the future with the results of similar surveys to detect changes in species distributions, relative abundances and habitat preferences.

Presence after three decades of red wood ants (Formica rufa group; Hymenoptera: Formicidae) in forests in an agricultural landscape

Conducting a repeat study of the presence of mound-building red wood ants (Formica rufa group) after a period of 30 years has rarely been done in Europe. From 1990 to 2020 such a study was done in an intensively used agricultural landscape with fragments of forest in the South-Eastern part of The Netherlands. In 1990, 280 nest mounds of three species of red wood ants and a hybrid were found in the forests and along forest edges. The highest occupancy was in forests of > 25 ha. The connectivity between the forest fragments mainly determined their presence. In 2020, only 160 nest mounds were found. The development of the colonies differed for Formica polyctena FĂśrster, 1850 (slight decrease), F. rufa Linnaeus, 1761 (substantial increase) and F. pratensis Retzius, 1783 (strong decrease). The differences between the species in this highly fragmented landscape may be due to differences in their colonization strategies of either nest splitting or producing swarms of young queens. Furthermore, the analyses show that the type of environment (in a forest or along a forest edge) determines the probability of extinction or settlement. There is a need to undertake management measures to prevent the extinction of species of red wood ants in the area studied. These measures include creating small clearings in dense forests, reducing shading due to overgrowing shrubs or herbaceous plants, and creating buffer zones around intensively manured fields. More long-term monitoring is needed in Europe to compare the circumstances in different regions, detect trends and evaluate the effects of protection measures.

Variation in the colour pattern of the narrow-headed ant Formica exsecta (Hymenoptera: Formicidae) in European Russia

We determined whether body colour patterns of the narrow-headed Formica exsecta ant can serve as a marker of adaptative strategies in heterogenous environments. The variations in colour were studied in two populations of F. exsecta in central and north western areas in European Russia. A generalised colour scheme of the head and three thorax segments is developed based on a comparative analysis of the colouration of F. exsecta and red wood ants (Formica s. str.). The scheme consists of 23 variants. We found that the colouration of different parts of the body varies independently to a large extent, although a pale (less melanized) head and three thoracic segments often co-occur with paler other parts of the body. We also show that the relationship between colour pattern and body size vary significantly in different complexes. We suggest that these colour variants can be used to study the spatial-temporal phenotypic differentiation of populations and adaptation of ants to microhabitats. The proposed scheme can be used as a convenient tool in future studies to quantify the variation in colour patterns. This scheme should be further tested for its applicability for other species of the subgenus Coptoformica.

CO2 biogeochemical investigation and microbial characterization of red wood ant mounds in a Southern Europe montane forest

Red wood ants are ecologically important species in Europe that form large colonies. Their nest mounds are characterized by stable microclimatic conditions, that are favourable to the development of rich invertebrate and microbial communities. Through their respiration processes, all these inhabitants contribute to the total gas emissions of the mounds. Quantifications of red wood ant mounds CO2 production are only available from Northern and Central Europe, and the Alps, where these ants are common. During the second half of the last century some species were transplanted from the Alps to southernmost sites, where they were not present, to be employed as biocontrol agents. No information on the contribution of these low-latitudes populations to the local forest CO2 production is available. The microbial communities living within red wood ant mounds are also poorly known. In this study, we investigated the CO2 gas emissions and the microbiome of the mounds of an introduced population of the red wood ant Formica paralugubris in a Southern Europe montane forest. We found that ant mounds produced more CO2 than the forest soil, and that their CO2 efflux as well as internal concentration were higher during summer than winter, with a lighter CO2 carbon isotopic signature in summer than winter, likely due to an increased ant activity. Moreover, the top part of the mound was characterised by higher CO2 efflux and lower CO2 internal concentration compared to the bottom, probably due to its internal structure and conditions. The isotopic signature of the mound material was similar between summer and winter, suggesting a metabolic similarity of the microbial communities. Also, we estimated the ants’ relative contribution to the total mound CO2 production to be 83%, whereas the microbiota CO2 contribution was estimated at 17%. Finally, the mound microbiome composition varied between summer and winter, though no seasonal difference in the diversity indexes or β-diversity was found. Our results demonstrate the impacts of the introduced red wood ants on the carbon dynamics of the recipient ecosystem.