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Lasius maltaeus Seifert, 2020 was recently described as a Maltese endemic ant based on quantitative morphology, after decades of uncertainties over the identity of the local population, which has a phenotype resembling L. emarginatus (Olivier, 1791). At the same time, Sicilian L. emarginatus populations were discovered to diverge in their mitochondrial DNA to a degree that suggested heterospecificity. Considering the biogeographic similarity of Malta and Sicily, with land bridges connecting them repeatedly until the last glacial maximum, we questioned the assumption that L. maltaeus was endemic to Malta. We integrated quantitative morphology and mtDNA in the study of the Maltese and southern Italian populations phenotypically close to L. emarginatus. We discovered that the range of L. maltaeus extends over most of Sicily, while the true L. emarginatus replace it in the north-eastern sector of the island, the nearby Aeolian Islands, and the Italian peninsula. The distributions of L. emarginatus and L. maltaeus in Sicily follow biogeographic patterns recalling the island’s complex paleogeographic history. Further investigations should verify the existence of truly Maltese endemic ants, since the status of other allegedly endemic species is not strongly supported.

There is insufficient information to identify most species of the myrmecophilous rove beetle genus Homoeusa. In this paper, after examining the type material, Homoeusa rufescens (Sharp, 1874) is redescribed in detail and its new allied species Homoeusa ovatasp. nov. is described. We also observed the behavior of these two species in the field; the behavior was similar to that reported for H. acuminata (Märkel, 1842). A checklist of Homoeusa from the Palearctic and Nearctic is also provided.

European bee-eater (Merops apiaster Linnaeus, 1758; Coraciiformes: Meropidae) is known as a bee-predator, but its food spectrum is variable and depends on the current supply. This is the first study focused on the ants (Hymenoptera: Formicidae) as important prey in the diet of the European bee-eater. In 2017, 9,604 insect prey was obtained from pellets gained from two colonies breeding: (1) underground of a grazed sand dune (Radvaň nad Dunajom) and (2) in the sandy wall (Gabcikovo) without pasture, both in southern Slovakia. Five ant taxa were identified, the list of ants in the bee-eater’s diet was expanded by three taxa Lasius sp., Camponotus vagus (Scopoli, 1763) and Liometopum microcephalum (Panzer, 1798). In summary, ants represent the second most abundant family (12.35 %) of total prey. Compared to adults, nestlings (15.04 %) ate significantly more ants than adults (10.97 %). To study the ants’ composition in the diet of bee-eater near to different types of habitats, the pellets of nestlings were chosen because they more accurately reflect the sources of insect during the breeding season. Differences in the feeding of the European bee-eater nestlings between the grazed and the non-grazed locality were confirmed, where Lasius sp. and Tetramorium sp. highly correlated with grazing site. Moreover, nestlings ate significantly more ants in the area, where an open habitat was managed by grazing (6.55 vs. 15.04 %). The presented research indicates the importance of traditional pastures in the country for ants and also for bee-eaters. These ecosystem engineers are likely to find more microhabitats on the pastures, which has also been reflected in the diet of the nestlings breeding on the grazed site.

Background The reproductive division of labor of eusocial insects, whereby one or several queens monopolize reproduction, evolved in a context of high genetic relatedness. However, many extant eusocial species have developed strategies that decrease genetic relatedness in their colonies, suggesting some benefits of the increased diversity. Multiple studies support this hypothesis by showing positive correlations between genetic diversity and colony fitness, as well as finding effects of experimental manipulations of diversity on colony performance. However, alternative explanations could account for most of these reports, and the benefits of diversity on performance in eusocial insects still await validation. In this study, we experimentally increased worker diversity in small colonies of the ant Lasius niger while controlling for typical confounding factors. Results We found that experimental colonies composed of workers coming from three different source colonies produced more larvae and showed more variation in size compared to groups of workers coming from a single colony. Conclusions We propose that the benefits of increased diversity stemmed from an improved division of labor. Our study confirms that worker diversity enhances colony performance, thus providing a possible explanation for the evolution of multiply mated queens and multiple-queen colonies in many species of eusocial insects. Supplementary Information The online version contains supplementary material available at 10.1186/s12862-021-01890-x.

Infections early in life can have enduring effects on an organism's development and immunity. In this study, we show that this equally applies to developing 'superorganisms'--incipient social insect colonies. When we exposed newly mated Lasius niger ant queens to a low pathogen dose, their colonies grew more slowly than controls before winter, but reached similar sizes afterwards. Independent of exposure, queen hibernation survival improved when the ratio of pupae to workers was small. Queens that reared fewer pupae before worker emergence exhibited lower pathogen levels, indicating that high brood rearing efforts interfere with the ability of the queen's immune system to suppress pathogen proliferation. Early-life queen pathogen exposure also improved the immunocompetence of her worker offspring, as demonstrated by challenging the workers to the same pathogen a year later. Transgenerational transfer of the queen's pathogen experience to her workforce can hence durably reduce the disease susceptibility of the whole superorganism.

We describe three new genera of cynipid oak gall wasps from the Nearctic: Burnettweldia Pujade-Villar, Melika & Nicholls, gen. nov., Nichollsiella Melika, Pujade-Villar & Stone, gen. nov., and Disholandricus Melika, Pujade-Villar & Nicholls, gen. nov. (Hymenoptera: Cynipidae: Cynipini). Burnettweldia includes five species, B. californicordazi Cuesta-Porta, Melika & Pujade-Villar, sp. nov., B. conalis (Weld), comb. nov., B. corallina (Bassett), comb. nov., B. plumbella (Kinsey), comb. nov., B. washingtonensis (Gillette), comb. nov.. Nichollsiella includes three species, N. arizonica (Cockerell), comb. nov., N. sulcata (Ashmead), comb. nov., and N. puigi Melika, Cuesta-Porta & Pujade-Villar, sp. nov.. Disholandricus includes four species, D. chrysolepidis (Ashmead), comb. nov., D. lasius (Ashmead), comb. nov., D. reniformis (McCracken & Egbert), comb. nov., D. truckeensis (Ashmead), comb. nov. The genus Paracraspis Weld, comb. rev. is re-established with three species, P. guadaloupensis (Fullaway), P. insolens (Weld), and P. patelloides (Trotter). Descriptions, re-descriptions, diagnoses, keys to genera and species are given, including data on DNA sequences, biology, phenology and distribution.

The ant fauna of Sicily, the largest island in the Mediterranean basin, has been significantly overlooked over the time. Drafting a reliable Sicilian ant checklist requires extensive field surveys, a careful review of the literature and of museum specimens, as well as the taxonomic investigation of some problematic issues. As a part of these ongoing efforts, we present our results on the presence or absence of 25 species. By analyzing specimens collected during the last 35 years across the island and reviewing old records in the light of present-day taxonomy, we provide evidence of the presence of 9 species (Camponotus ruber, Lasius myops, L. platythorax, Plagiolepis schmitzii, Ponera testacea, Solenopsis orbula, Temnothorax clypeatus, T. nylanderi, and T. ravouxi), while suggesting the absence of 19 others (Camponotus ligniperda, C. sicheli, C. spissinodis, Formica lugubris, Lasius alienus, L. flavus, L. niger, L. paralienus, Messor minor, M. wasmanni, Monomorium monomorium, Myrmica scabrinodis, M. spinosior, Nylanderia sp. 2 sensu Schifani & Alicata 2018, Solenopsis fugax, Temnothorax luteus, T. tuberum, Tetramorium caespitum, and T. indocile). Similar studies are necessary across Italy, as a significant portion of the existing ant records is outdated due to the evolved taxonomic framework.

The predator-predator naïveté hypothesis suggests that non-native predators benefit from being unknown to native predators, resulting in reduced intraguild interference with native predators. This novelty advantage should depend on the ability of native predators to recognize cues of non-native predators. Here, we compared ant aggression and lady beetle reaction in four native and the invasive lady beetle species Harmonia axyridis. In addition, we tested whether lady beetle cuticular hydrocarbons (CHCs) are involved in species recognition, which might explain naïveté if the invasive species has a specific CHC profile. To this end, we conducted behavioral assays confronting two native ant species with both living lady beetles and lady beetle elytra bearing or lacking CHCs of different lady beetle species. Finally, we characterized CHC profiles of the lady beetles using GC–MS. In general, the aggression of Lasius niger was more frequent than that of Myrmica rubra and L. niger aggression was more frequent towards most native lady beetle species compared to H. axyridis. The removal of CHCs from lady beetle elytra reduced aggression of both ant species. If CHCs of respective lady beetle species were added on cue-free elytra, natural strength of L. niger aggression could be restored. CHC analyses revealed a distinct cue composition for each lady beetle species. Our experiments demonstrate that the presence of chemical cues on the surface of lady beetles contribute to the strength of ant aggression against lady beetles. Reduced aggression of L. niger towards H. axyridis and reduced avoidance behavior in H. axyridis compared to the equally voracious C. septempunctata might improve the invasive lady beetle’s access to ant-tended aphids.

As a model species to study the geographic variation of cold hardiness in insects, we use ants Lasius flavus from populations of territories separated by thousands of kilometers (southern Finland, the Moscow region, and Amur oblast) and with contrasting climates, from maritime variants to climates differing in degrees of continentality. We measure supercooling points (SCPs) and the temperature at which 50% of the sample perishes (LT50%) and evaluate overwintering conditions. The data on L. flavus are compared to similar data obtained on L. niger, аs well as to similar measurements in separate nests of L. alienus, L. psammophilus, and L. fuliginosus, which were published earlier. The workers of L. flavus and L. niger have similar values of cold hardiness (LT50% from –13 to –15°C, minimum average SCP from –24 to –25°C), although these species inhabit different climatic zones and arrange their overwintering chambers at different depths. Such resistance to long-term exposure to negative temperatures is more than sufficient for overwintering, even in the coldest of the studied areas (village of Arkhara, Amur oblast), where the average minimum temperature in January in the ant overwintering chambers at a depth of 50 cm does not fall below –6°C. The variation in cold hardiness and higher values of its parameters in other studied ant species are due to their insufficient preparedness for overwintering. However, the narrow range of SCP values (from –27 to –29°C) in the most cold-resistant individuals of all studied species strongly suggests that their average SCP and LT50% values are similar to those of L. flavus and L. niger. The similar (or perhaps identical) cold hardiness of the studied ant species appears to be a stable trait of the genus Lasius, as was demonstrated for another ant genus, Myrmica, and which is dissimilar to the genus Formica, in which different species have individual characteristics of cold-resistance. Excessive for overwintering in the warmer climate (southern Finland and Estonia), such cold hardiness appears to have no adaptive value. It can be considered a byproduct of diapause, which is manifested in preadaptation to withstand negative temperature. However, it was this cold hardiness that allowed the ant species to colonize the vast territory of southern Siberia and the Far East.

Among actinobacteria associated with ants Camponotus vagus, Formica cunicularia, and Lasius niger, their nests, and intact soils, cellulolytic activity was screened in medium with carboxymethyl cellulose (CMC) using Congo Red dye. Assessment of culture fluids of tested strains on the CMC-plates and comparing them with solutions of the commercial cellulase preparation allowed for quantifying their activity. Data were confirmed by evaluating endo-1,4-glucanase activity using the 3,5-dinitrosalicylic acid (DNS) method. The three most active strains of actinobacteria were isolated from ants Camponotus vagus, Lasius niger, and Formica cunicularia and belonged to the genus Streptomyces. The 16S rDNA sequences of the strains Streptomyces sp. Fu2, Streptomyces sp. Ln9, and Streptomyces sp. Pe3 were deposited in the GenBank under accession numbers MN227506, MN227508, and MG 705182, respectively. Specific endoglucanase and β-glucosidase activity of these strains corresponded to that of cellulose- and lignin-destroying streptomycetes described in the literature.

Description of Lasius ponderosae sp. nov. Lasius ponderosae Schär, Talavera, Rana, Espadaler, Cover, Shattuck and Vila. ZooBank LSID: urn:lsid:zoobank.org:act: 22E2743A-2F1C-4870-B318-A1F2DF2B464C Etymology: ponderosae alludes to the ponderosa pine tree (Pinus ponderosa) that is at the centre of occurrence in the ponderosa pine—gambel oak communities in the western Rocky Mountains and northern Arizona. Type material: located at the Museum of Comparative Zoology, Cambridge, USA. Two paratype workers each will be deposited at the collections of University of California Davis (UCDC), the University of Utah (JTLC) and the Natural History Museum of Los Angeles County (LACM). Holotype: worker, Fig. 3a–c. Type locality: USA, Utah: Uintah Co., Uintah Mtns., 2408 m. 18.6 mi N. Jct. Rt. 40 on Rt. 191, 40.66378°N, − 109.47918°E, leg. 15.VII.2013, S. P. Cover; J. D. Rana, collection code SPC 8571. Measurements [mm]: HL: 0.899, HW: 0.823, SL: 0.821, EL: 0.239, EW: 0.189, ProW: 0.56, ML: 1.069, HTL: 0.863, CI: 92, SI: 100. Paratypes: 15 workers, two gynes (Fig. 3d–f), two males (Fig. 3g –i) from the same series as the holotype, morphometric data is given in the Appendix, Table S 5 and Table S 6. CO 1 mitotype h17: Genbank Accession no. LT 977508. Description of the worker caste: A member of a complex of cryptic species resembling L. niger. Intermediate in overall body size, antennal scape length and eye size and comparable to related species (Table 1). Terminal segment of maxillary palps and torulo-clypeal distance relative to head size shorter than in related Palearctic species (Table 1). Mandibles with 8 or rarely 7 or 9 regular denticles and lacking offset teeth at their basal angle. Penultimate and terminal basal mandibular teeth of subequal size, and the gap in between with subequal area than the basal tooth. Anterior margin of clypeus evenly rounded. Dorsofrontal profile of pronotum slightly angular (Fig. 4a). Propodeal dome short and flat, usually lower than mesonotum (Fig. 4a). Body with abundant and long pilosity, especially lateral propodeum, genae, hind margin and underside of head. Pilosity of tibiae and antennal scapes variable, ranging from almost no setae (" L. alienus "-like phenotype) to very hairy (" L. niger "-like phenotype). Microscopic pubescent hairs on forehead between frontal carinae long and fine. Clypeus typically with only few scattered pubescent hairs (Figs. 3, 4c). Coloration of body dark brown, occasionally yellowish- or reddish-brown or slightly bicolored with head and thorax lighter than abdomen. Femora and antennal scapes brown. Mandibles and distal parts of legs yellowish to dark brown. Specimens of all 3 castes are shown in Fig. 3a–i and morphometric data are summarized in Table 1 and raw measurements are available in Table S 5 and S 6. Diagnosis: Lasius ponderosae sp. nov. workers key out to " L. niger " using Wilson’s 1955 key to the Nearctic Lasius species. However, some populations with reduced pilosity may also be identified as " L. alienus " using this key. Lasius alienus is a Eurasian species not known from North America 33. The Nearctic " L. alienus " sensu Wilson (1955) includes both, L. americanus as well as populations of L. ponderosae sp. nov. with sparse setae counts on tibia and/or scapes. Lasius ponderosae sp. nov. can be distinguished from L. americanus by the presence of abundant, long setae surpassing the sides of the head in full face view (nGen> 5 and nOcc> 10 vs. nGen L. americanus). Distinguishing Lasius ponderosae sp. nov. from related Eurasian species (e.g., L. niger or L. platythorax) by subjective eye inspection is difficult because there are no easily visible morphological traits allowing a separation of Lasius ponderosae sp. nov. from all these taxa. Lasius ponderosae sp. nov. is therefore a cryptic species. For L. niger, introduced to North America, nest samples can ofen be distinguished from L. ponderosae sp. nov. using the average mesosoma profile (Fig. 4a,b) and by fewer pubescent hairs on the clypeus (Fig. 4c,d). A distinction between single workers of L. ponderosae sp. nov. and L. niger, L. platythorax and related Palearctic species can be achieved by calculating the following discriminant function with measurements taken in mm: D = − 43.792* GUHL + 113.436*dCLAN + 75.68* MP 6 − 0.431*nSt − 10.075. Negative values of D indicate L. ponderosae sp. nov. (L. ponderosae sp. nov., n = 39, median, range: − 3.18 [− 5.83, − 0.43]; L. niger, L. platythorax, L. grandis, L. japonicus and L. cinereus, n = 49, median, range: 2.67 [0.18, 4.61]). A principal component analysis plot for the four most diagnostic variables (GUHL, dCLAN, MP 6 and nSt) is shown in Fig. 5. For a definition of the variables used in the function, see Supplementary Table S 4 and Supplementary Fig. S1. All morphometric data are available in Table S 6. Distribution: Western North America: Alberta, Arizona, Baja California, California, Colorado, Idaho, Montana, Nevada, Oregon, Utah and Washington 53. Habitat: Occurring in a broad range of habitats and elevations, from 20–3220 m a. s. l. (mean: 1997 m) 53. Typical for mid-elevations in the mountains, whose primary habitat is ponderosa pine forest and its associated communities (e.g., dry meadows, sagebrush, gambel oak woodland) or at higher elevations in meadows bordered by aspen-spruce or alpine scree slopes, but also in other habitats. Nests in and under dead wood, and under stones in soil 53.

In insect societies, the balance between exploitation of known resources and exploration of new ones is important to ensure sufficient resources. Mass recruiting ants, such as Lasius niger, use pheromone trails to recruit nestmates to a newly discovered food source. Pheromone following, however, shows characteristic non‐following (lapse) rates among different species, with ∼20% of L. niger foragers ignoring pheromone. These characteristic lapse rates might simply be ‘noise’, or they might indicate a subset of specialised explorative foragers, a scouting caste, that consistently ignores pheromone in order to explore. Here we show pheromone ignoring is not a repeatable behaviour in L. niger foragers – ants who did not follow a trail were no more likely to ignore it again an hour later than ants which did follow it. Our findings suggest that there is no subset of specialised pheromone‐ignoring L. niger foragers. This may be due to their moderate colony size and strong reliance on individual memories: species with larger colony sizes or a weaker reliance on private information (i.e. memory) may have specialist non‐followers. Our work raises the question: what is a scout ant? We encourage future research to investigate the presence of a scouting caste in other ant species using our straightforward methodology, as a social information‐ignoring caste may be rarer than expected.

1. Climate change will likely affect the association between species interacting at different trophic levels. However, studies focusing on the impact of an elevation of temperature on ant‐hemipteran mutualism remain scarce. 2. In the present study we investigated, in laboratory conditions, the foraging behaviour of the ant Lasius niger and its mutualistic interaction with the aphid Aphis fabae under three conditions of temperatures (i.e. 20°C, 23°C, and 26°C), as predicted by climatic scenarios. 3. Aphids were more mobile but as likely to release honeydew droplets at higher temperatures. As regards the ants, a moderate 3°C increase of temperature positively impacted their mutualistic interaction with aphids. Such reinforcement was achieved through an increase in the walking speed of ant foragers, in the number of mobilised ants as well as in the total amount of honeydew harvested by the colony. 4. A further elevation of temperature to 26°C reduced the benefits gained by the aphid‐tending ants, in terms of lower amount of collected honeydew. 5. Based on our results, we hypothesise that, in temperate regions, a moderate increase of ambient atmospheric temperature by 3°C will benefit to the L. niger ‐ A. fabae mutualistic interaction. A more marked elevation of 6°C may represent a threshold thermal value above which a switch of partners or a disruption of the interaction may occur under the temperatures predicted for the end of the century. These results demonstrate the fragility of mutualistic interactions, and more particularly their sensitivity to temperature increases predicted by realistic forecast models.

Insects can be very good learners. For example, they can form associations between a cue and a reward after only one exposure. Discrimination learning, in which multiple cues are associated with different outcomes, is critical for responding correctly complex environments. However, the extent of such discrimination learning is not well explored. Studies concerning discrimination learning within one valence are also rare. Here we ask whether Lasius niger ants can form multiple concurrent associations to different reward levels, and how rapidly such associations can be learned. We allowed individual workers to sequentially feed on up to four different food qualities, each associated with a different odour cue. Using pairwise preference tests, we found that ants can successfully learn at least two, and likely three, odour/quality associations, requiring as little as one exposure to each combination in order for learning to take place. By testing preference between two non-extreme values (i.e. between 0.4 M and 0.8 M having been trained to the qualities 0.2, 0.4, 0.8 and 1.6) we exclude the possibility that ants are only memorising the best and worst values in a set. Such rapid learning of multiple associations, within one valence and one modality, is impressive, and makes Lasius niger a very tractable model for complex training paradigms.

Humans usually assess options not in terms of absolute value, but relative to reference points. The framing of alternatives can strongly affect human decision-making, leading to different choices depending on the context within which options are presented. Similar reference-point effects have been recently reported in ants, in which foragers show contrast effects: Ants overvalue a medium-quality food source if they were expecting a poor one, and vice versa for expectations of good food. However, studies of human consumer psychology have demonstrated that expectations, for instance, from product labels, can drive value perception in the opposite direction, via a process of assimilation. For example, an expensive bottle of wine is perceived as more enjoyable compared with a cheaper bottle, even if the wine is the same. In this study, we demonstrate a similar labeling-association effect in an insect: Ants showed assimilation effects by spending twice as long drinking at medium-quality food if it was scented with an odor previously associated with high quality than if it was scented with a poor-quality label. The presence of odor cues in the food during consumption and evaluation is critical, as without them, odor-driven expectations of quality result in contrast, not assimilation effects. The addition of a quality label in the food thus reverses contrast effects and causes value to be aligned with expectations, rather than being contrasted against them. As value judgment is a key element in decision-making, relative value perception strongly influences which option is chosen and ultimately how choices are made. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

This review investigates ant-aphid mutualism (trophobiosis), in particular focusing on evolutionary processes in aphids resulting from this interaction. This broad literature review allows us to revise existing views on certain aspects of this mutualism and provide the first timeline of its possible development over a geological timescale. We propose a new classification of ant-aphid mutualism with respect to its ecological characteristics and present new explanations of the development of certain morphological structures of aphids as resulting from adaptation to a trophobiotic relationship with ants. In light of these findings, the presence of the so-called 'trophobiotic organ' in all myrmecophilous aphids is questioned. We review various communication modes between aphids and mutualistic ants and the possible influence of this symbiosis on modifications of aphid life cycles. Recent evidence on the suspected role of endosymbiotic bacteria in the development of mutualism is discussed. Finally, we propose a first timeline of ant-aphid interactions leading to the development of particular adaptations of aphids to mutualism, from general interactions between diverging Aphidomorpha and ants in the late Mesozoic to more specific coevolution between the aphid tribe Fordini and the ant genus Lasius.

Termites are generally regarded as pests, although they have some beneficial roles to play in the ecosystem, particularly in the soil. This study was conducted between January 2018 and April 2018, to determine the effect of physico-chemical parametrs on abundance and diversity of termites and other arthropods in termite mounds in Uinversity of Uyo Community. Soil samples were randomly collected from six termite mounds from two sites for physiochemical parameters analysis and these were temperature, pH, moisture content, nitrogen, phosphorus, magnesium, copper, sodium, potassium, manganese and iron.. The termites and other arthropods were preserved in 70% ethanol. Temperature and moisture content, copper, sodium and iron were significant. The results revealed that the physicochemical parameters affected the termite species abundance as station 1 (539) had relatively more of the termite species than station 2 (551), and also affected the diversity of the termites as station 1 (0.89) had relatively more diversity of the termites than station 2 (0.66). Also from the results, station 1 (2.06) had relatively more diversity of the other arthropod species identified in the study area than station 2 (1.59). Macrotermes bellicosus and Odontermes badius termite species were identified. Musca domestica, Anopheles gambiae, Lasius sp, Archispirostreptus sp, Camponotus sp, Missulena sp, Chorthippus sp, Acheta sp and Blatta orientalis were the other arthropods collected and identified. Macrotermes bellicosus (59.93 %; 63.52 %) was the most abundance and dorminant of the termite species identified in the study areas. Lasius sp (45; 25.93 %)

Introduction . Industrial emissions affect the impoverishment of insect fauna not only by reducing their species composition but also by reducing the abundance of dominant species. Aim . Therefore, the goal of the research was to investigate how the cement dust affects species diversity of ants, density and types of anthills. Methods . Investigation of the effect of cement dust on mirmecofauna was carried out on the territory of village Yamnytsia, Tysmenytsia district, Ivano-Frankivsk region and its vicinity, near the cement plant of PJSC «Ivano-Frankivskcement». Meadows and deciduous forests were studied within the village of Yamnytsia, which are located at different distances from the source of cement dust (0; 0.5 km; 1 km; 5.5 km) and 30 km from the village boundary (control). To quantify the species composition of Formica ants, the methods of K. V. Arnoldi were used. Counting of anthills and sampling of ants was performed according to the method of G. M. Dlussky. Anthills were described by the standard method, the account of the building material of the nests was carried out visually, the material was not selected. Results . Analyzing the distribution of ants genera and species on the experimental meadows, we found a direct correlation between the number of ants and the distance from the sources of cement dust (r=0.87 at p

Myrmecophilous insects depend on their ant hosts during at least part of their life cycle. Lasius ants appear to be primarily involved as host in myrmecophilous interactions, especially with aphids and beetles, e.g. staphylinid. Pella laticollis is a rove beetle having a close ecological association with Lasius fuliginosus, which is correlated to its behavior adapted to avoid attack. Microorganisms can also play an important role in the maintenance of such relationships. We used 16S rRNA sequencing on the Illumina MiSeq platform to identify the bacterial communities associated with larvae and adults of both L. fuliginosus and P. laticollis. In addition, we determined the microbiota profiles of the nest-carton, an organic material lining the nest chambers. We obtained more than two million good quality reads. Taxonomic annotation showed that the profiles consisted of a total of 20 phyla, among which Proteobacteria was the most abundant. The samples were grouped according to the host’s developmental stage or the nest material, and the differences between those groups were significant. Only the microbiota of L. fuliginosus larvae and adults did not differ significantly. Analyses at the genus level indicated a heightened abundance of Pseudomonas in the insects’ profiles. The bacterial communities associated with the nest-carton included bacterial genera recorded from soil and dead wood. The profiles showed the presence of two well-known endosymbiotic bacteria, namely, Rickettsia and Wolbachia. According to our findings, the bacterial communities associated with larvae and adults of both L. fuliginosus and P. laticollis formed clusters according to the host’s identity and its developmental stage. The profiles determined for the nest-carton formed a separate group. Our study is in line with a new research trend that is focusing on microbiota associated not only with ants, but also with myrmecophiles and ant nests inhabited by those species.

Genus Lasius Fabricius, 1804 = Donisthorpea Morice and Durrant, 1915. = Acanthomyops Mayr, 1862 syn.rev. = Austrolasius Faber, 1967 syn.nov. = Cautolasius Wilson, 1955 syn.nov. = Chthonolasius Ruzsky, 1912 syn.nov. = Dendrolasius Ruzsky, 1912 syn.nov. Type species. Formica nigra Linnaeus, 1758 (= L. niger). Subgeneric classification remarks. The modern body of taxonomic work on Lasius was initiated by Wilson���s revision of the genus (Wilson, 1955), which was classified into four subgenera at the time: Cautolasius, Chthonolasius, Dendrolasius, and Lasius s. str. In this work, Wilson provided a phylogeny of Lasius (Fig. 1A), but this treatment was an intuitive account of what he considered trends in the evolution of the morphology and biogeography of the genus. Subsequently, the subgenus Austrolasius was erected for a few socially parasitic species (Faber, 1967), andthe former genus Acanthomyops was included in Lasius as the sixth subgenus (Ward, 2005). The first phylogenetic inference based on molecular data was presented by Hasegawa (1998), who used COI to investigate relationships of four Lasius species (phylogeny not figured here). Since then, two major attempts at resolving the phylogeny were presented by Janda et al. (2004) and Maruyama et al. (2008) (Fig. 1B, C). Both studies used a combination of morphological characters and molecular data, including mitochondrial markers (COI, COII, tRNA-Leu, 16S). Amore recent effort focused on the phylogeny of European species related to L. niger (Lasius s. str.) and included nuclear genes LW Rh and wg in addition to 16S and COI (Talavera et al., 2015). To date, the monophyly of the subgenera has not been questioned except for the nominotypical subgenus (Janda etal., 2004; Maruyama etal., 2008). Recently, Seifert (2020, p. 21) stated that there is clear justification for elevating the subgenera to generic status. Such an action would considerably complicate the classification of the Lasius genus group because of the robustly supported paraphyly of the subgenera that we have uncovered here (Figs 1D, 2, S 1, Table 4). Specifically, in order to retain monophyly at the genus rank, four new genera would need to be erected for the species groups of brunneus, nearcticus, atopus, and pallitarsis. An additional issue would be the placement of the species which have not been sequenced, particularly those of the niger species group and, for example, the recently described L. brevipalpus Seifert, which is incertae sedis in the niger clade. The strongest morphological reorganization at the generic or subgeneric levels would be to recognize the reciprocally monophyletic niger and flavus clades as Lasius and Acanthomyops, respectively, but we refrain from doing so here (for our rationale, see ���Species group classification of Lasius ��� below). Comments on extant species. We determine that one species, Lasius escamole Reza should be excluded from Lasius and considered a junior synonym of the dolichoderine Liometopum apiculatum Mayr syn.nov. Reza (1925) described L. escamole in the context of a cultural study on the eponymous traditional Mexican dish known tobe made from the larvae of L. apiculatum (Hoey-Chamberlain et al., 2013). Although Reza���s description and illustrations are extremely vague, it is possible to see details that point to a dolichoderine identity. In the figures of the original description, the mandibles have long masticatory margin and small, sharp, even denticles, the ventral metasoma is shown as a slit-like anal opening rather than a formicine-like acidopore, and various figures display the fine, dense, appressed pilosity characteristic of Liometopum Mayr, but no erect setae as expected for Lasius. Many species have been added to Lasius since Wilson���s revision, mostly in Europe and Mediterranean, while North American taxa have largely remained untreated except for a thorough revision of Acanthomyops (Wing, 1968a, 1968b). Careful research has revealed multiple Palaearctic Lasius species that show only subtle morphological differentiation from close relatives (Seifert, 1983, 1990, 1991, 1992, 2020; Schlick-Steiner et al., 2003). There is no reason to believe that North America does not harbour a diverse fauna of such ���cryptic species���. For example, the question of the putative Holarctically distributed Lasius species was resolved by Sch��r et al. (2018) who elevated to species rank the American representatives of L. alienus, L. flavus, and L. umbratus Nylander, recognizing the following revived taxa, in order: L. americanus Emery, L. brevicornis Emery, and L. aphidicola (Walsh). Renewed focus on the Nearctic fauna is necessary, as is expanded sequencing at the global scale. Comments on extinct species. Without having scored the Baltic Lasius fossils other than ��� L. schiefferdeckeri, that is, ��� L. punctulatus Mayr and ��� L. nemorivagus Wheeler, we are unable to quantitatively address their placement. Historically, ��� L. punctulatus and ��� L. schiefferdeckeri were considered to be members of Lasius s. str. (Wilson, 1955; Dlussky, 2011), while the queen-based ��� L. nemorivagus was placed in Chthonolasius (Wilson, 1955) later to be implicitly considered incertae sedis in the genus (Dlussky, 2011). Our combined-evidence dating analyses recover ��� L. schiefferdeckeri as sister to or within the Lasius genus group (Figs 4, S 7���S 9). As the specific relationship of the fossil to the extant species of the Lasius genus group is uncertain, we conservatively consider the fossil incertae sedis in Lasius. There remains the possibility that ��� L. schiefferdeckeri is ancestral to the extant niger clade and is indicative of low rates of phenotypic transformation, as suggested by Mayr (1868), Wheeler (1915), and Wilson (1955). The placement of ��� L. schiefferdeckeri may be refined in future study by scoring characters which are explicitly derived from comparison of the brunneus and niger groups within the niger clade. The two differentiating traits proposed for the brunneus and niger groups are, on average, < 8 mandibular teeth in the brunneus group (Seifert, 1992; some niger group species with < 8), and presence of a subapical cleft in the mandibles of brunneus group males (Wilson, 1955). While ��� L. schiefferdeckeri demonstrates both a tooth count of < 8, and presence of a subapical cleft, the latter character is probably plesiomorphic of the Lasius genus group, and the polarity of the former is uncertain. Notably, Wilson (1955) observed that the male mandibles of ��� L. schiefferdeckeri are observed to vary from the ��� brunneus form��� to the derived ��� niger form���. With these three traits in mind, it does seem reasonable that ��� L. schiefferdeckeri is stem to or directly ancestral to the niger clade. Note on biology. Despite the interest in this genus, however, basic natural history remains unknown for many species, including the morphologically aberrant L. atopus and the species we sequence here, ��� L. nr. atopus ���. Only a handful of recently published studies have addressed the behaviour of some of the more rarely encountered species (e.g., Raczkowski & Luque, 2011), indicating that more effort is needed to elucidate the biology of Lasius., Published as part of Boudinot, Brendon E., Borowiec, Marek L. & Prebus, Matthew M., 2022, Phylogeny, evolution, and classification of the ant genus Lasius, the tribe Lasiini and the subfamily Formicinae (Hymenoptera: Formicidae), pp. 113-151 in Systematic Entomology 47 on pages 135-136, DOI: 10.1111/syen.12522, http://zenodo.org/record/5975346, {"references":["Fabricius, J. C. (1804) Systema Piezatorum Secundum Ordines, Genera, Species, Adjectis Synonymis, Locis, Observationibus, Descriptionibus. Brunswick: C. Reichard. xiv + 15 - 439 + 30 pp.","Faber, W. (1967) Beitrage zur Kenntnis sozialparasitischer Ameisen. I. Lasius (Austrolasius n. sg.) reginae n. sp., eine neue temporar sozialparasitische Erdameise aus Osterreich (Hym. Formicidae). 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C. (2008) A DNA and morphology based phylogenetic framework of the ant genus Lasius with hypotheses for the evolution of social parasitism and fungiculture. BMC Evolutionary Biology, 8, 1 - 15. Article 237. https: // doi. org / 10.1186 / 1471 - 2148 - 8 - 237.","Talavera, G., Espadaler, X. & Vila, R. (2015 2014) Discovered just before extinction? The first endemic ant from the Balearic Islands (Lasius balearicus sp. nov.) is endangered by climate change. Journal of Biogeography, 42, 589 - 601. https: // doi. org / 10.1111 / jbi. 12438.","Seifert, B. (2020) A taxonomic revision of the Palaearctic members of the subgenus Lasius s. str. (Hymenoptera, Formicidae). Soil Organisms, 92, 15 - 86.","Reza, A. (1925) Recursos alimenticios de Mexico de origen animal poco conocidos. Memorias y Revista de la Sociedad Cientifica \" Antonio Alzate \", 44, 1 - 22.","Hoey-Chamberlain, R., Rust, M. K. & Klotz, J. H. (2013) A review of the biology, ecology and behavior of velvety tree ants of North America. Sociobiology, 60, 1 - 10.","Wing, M. W. (1968 a) Taxonomic revision of the Nearctic genus Acanthomyops (Hymenoptera: Formicidae). Memoirs of the Cornell University Agricultural Experiment Station, 405, 1 - 173.","Wing, M. W. (1968 b) A taxonomic revision of the Nearctic genus Acanthomyops Mayr (Hymenoptera: Formicidae). [Abstract.]. Dissertation Abstracts. B. Sciences and Engineering, 28, 3934.","Seifert, B. (1983) The taxonomical and ecological status of Lasius myops Forel (Hymenoptera, Formicidae) and first description of its males. Abhandlungen und Berichte des Naturkundemuseums Gorlitz, 57, 1 - 16.","Seifert, B. (1990) Supplementation to the revision of European species of the ant subgenus Chthonolasius Ruzsky, 1913 (Hymenoptera, Formicidae). Doriana, Supplemento agli Annali del Museo Civico di Storia Naturale \" G. Doria \". GEN, 6, 1 - 13.","Seifert, B. (1991) Lasius platythorax n. sp., a widespread sibling species of Lasius niger (Hymenoptera: Formicidae). Entomologia Generalis, 16, 69 - 81.","Seifert, B. (1992) A taxonomic revision of the Palaearctic members of the ant subgenus Lasius s. str. (Hymenoptera: Formicidae). Abhandlungen und Berichte des Naturkundemuseums Gorlitz, 66, 1 - 67.","Schlick-Steiner, B. C., Steiner, F. M., Schodl, S. & Seifert, B. (2003) Lasius austriacus sp. n., a central European ant related to the invasive species Lasius neglectus. Sociobiology, 41, 725 - 736.","Schar, S., Talavera, G., Espadaler, X., Rana, J. D., Anderson, A. A., Cover, S. P. & Vila, R. (2018) Do Holarctic ant species exist? Trans-Beringian dispersal and homoplasy in the Formicidae. Journal of Biogeography, 45, 1 - 12. https: // doi. org / 10.1111 / jbi. 13380.","Dlussky, G. M. (2011) The ants of the genus Lasius (hymenoptera, Formicidae) from late Eocene European ambers. Vestnik Zoologii, 45, 209 - 222.","Mayr, G. 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Most known species of entomopathogenic nematodes (EPNs) are generalist obligate parasites of insects. They kill their hosts within days after infection and mortality is mainly caused by toxins produced by bacteria that co-infect the hosts and serve as food for the nematodes. EPNs can infect a very broad spectrum of insects and these insects can therefore be expected to have evolved strategies to avoid infection. Indeed, ants are known to avoid feeding on EPN-infected insect cadavers, most likely because they are repelled by semiochemicals that emanate from the cadavers. The source and nature of these repellents are so far unknown. In a series of behavioral and chemical analytical experiments we identified hexadecanal and 2-heptadecanone as two compounds that are emitted by insect larva that are infected by the EPN Steinernema feltiae, but not by uninfected larvae. When spiking honey water with the two semiochemicals, they were confirmed to be highly deterrent to the ant Lasius niger. The environmentally benign hexadecanal and 2-heptadecanone could be employed to ward off ants and possibly other pests. Additional experiments are needed to fully determine their application potential., Open Access funding provided by Université de Neuchâtel. This work was supported by grant 31003A_166632 from the Swiss National Science Foundation.