Ant Lasius Flavus Research Articles

Differential transport of a guild of mutualistic root aphids by the ant Lasius flavus.

Mutually beneficial associations are widespread in ecological networks. They are typically assembled as multispecies guilds of symbionts that compete for one or more host species. The ant Lasius flavus engages in an intriguing and obligate mutualistic association with a community of aphids that are cultivated on plant roots in its nests. The ant displays a repertoire of amicable behaviors toward the aphids, including their transport. I examined whether L. flavus preferentially carried some of the root aphids. Using a no-choice and a choice experiment, I comparatively analyzed the transport rate of 5 obligate and one loosely associated species back to the ant nest and used the transport rate of the ant larvae as a reference. All associated root aphids were carried back to the nest, but in a clear preferential hierarchy. Geoica utricularia, Forda Formicaria, and Trama rara were rapidly transported, but slower than the own larvae. Tetraneura ulmi and Geoica setulosa were collected at a moderate rate and the loosely associated Aploneura lentisci was slowly retrieved. In contrast, different species of unassociated aphids were not transported and even provoked aggressive behavior in L. flavus. This study revealed that co-occurring symbionts may induce different degrees of host attraction, which ultimately may affect the coexistence and assembly of ant-symbiont communities.

The role of ant nests in European ground squirrel’s (Spermophilus citellus) post-reintroduction adaptation in two Bulgarian mountains

The European ground squirrel (Spermophilus citellus) is a vulnerable species, whose populations are declining throughout its entire range in Central and South-Eastern Europe. To a great extent, its conservation depends on habitat restoration, maintenance and protection. In order to improve the conservation status of the species, reintroductions are increasingly applied. Therefore, researchers focus their attention on factors that facilitate these activities and contribute to their success. In addition to the well-known factors like grass height and exposition, others, related to the underground characteristics, are more difficult to evaluate. The presence of other digging species could help this evaluation. Here, we present two reintroduced ground squirrel colonies, where the vast majority of the burrows are located in the base of anthills, mainly of yellow meadow ant (Lasius flavus). This interspecies relationship offers numerous advantages for the ground squirrel and is mostly neutral for the ants. The benefits for the ground squirrel, including reduced energy demand for digging, as well as additional surveillance and hiding places available, could greatly enhance the post-reintroduction adaptation process.

Behavioural development, fat reserves and their association with productivity in Lasius flavus founding queens

Reproduction-related behaviours are key components determining individual fitness. Many behavioural traits are linked, and such trait associations often affect fitness. Here, we combine behavioural and physiological data during two critical time points of founding queens (early and late nest-founding stage) in the claustral ant Lasius flavus to assess how these factors affect their initial productivity. We show that most behavioural traits, except brood care behaviour, are plastic during queen development and demonstrate that there are alternative behavioural pathways to achieve high productivity under standardised conditions. These results indicate that queens can utilise multiple behavioural trait combinations to maximise reproductive output at the earliest, and arguably most critical, time of colony foundation.

Myrmecophilous pygmephoroid mites (Acari: Pygmephoroidea) associated with Lasius flavus (Hymenoptera: Formicidae) in Russia.

Twenty four species of pygmephoroid mites (Acari: Pygmephoroidea: Neopygmephoridae, Scutacaridae, Microdispidae) are recorded from the ant Lasius flavus (Fabricius) or from its nests from Western Siberia and Crimea. Four of them of the genus Scutacarus Gros, 1845 (Acari: Scutacaridae), S. insolitus sp. nov., S. heterotrichus sp. nov., S. moseri sp. nov. and S. sibiriensis sp. nov. are described as new for science. Four species of scutacarid mites are recorded for the first time in Russia. The comparison of pygmephoroid mite communities associated with Lasius flavus from Crimean and West Siberian populations and notes on phoresy of pygmephoroid mites on ants are provided.

The diversity of soil mites (Acari: Mesostigmata) in yellow ant (Lasius flavus) nests along a gradient of land use

Mesostigmatid mites communities in yellow ant (Lasius flavus) hills and phoresis of mites on this ant species were analysed in the Wielkopolska Region, Central Poland. Samples were collected from ant nests located along a gradient of four different types of land use: forest, ecotone, meadow and garden. In total, 132 mites were collected in ant nests among which 26 species were identified. The highest total abundance of mites was observed in the ecotone. Moreover, 14 mite specimens were found on L. flavus workers bodies. These are the first records of phoresis of mesostigmatid mites on this ant species.

Linking ecosystem modification by the yellow meadow ant (Lasius flavus) to microbial assemblages in different soil environments

The mound building ant Lasius flavus can sustain many large colonies in extensively managed grassland ecosystems. L. flavus employs specialised nesting strategies in various soil environments, with distinctive mounds possibly constructed to obtain optimal environmental conditions regardless of nest location. As such, L. flavus is an important ecosystem engineer, and by modifying the environment they may affect other organisms. Ten replicate L. flavus nests were chosen from grasslands on soils from different parent material (limestone, peat, sandstone and shale) and compared to similar, nearby ant-free soil. Ecosystem modification was assessed by characterising soil physico-chemical properties and measuring the diversity of general bacteria, general fungi and nitrogen-fixing bacteria. For all soil types L. flavus significantly altered physico-chemical properties. This may be associated with greater microbial activities and highly different microbial assemblages within nests compared to reference soils. Overall, pH and moisture content significantly explained differences in assemblages of bacteria, fungi and nitrogen-fixing bacteria between the nest and reference soils. It remains unclear whether L. flavus directly or indirectly influenced soil microbial assemblages. Forming unique micro-habitats within grassland ecosystems, L. flavus mounds may contribute to the diversity of these ecosystems and understanding processes involved within these micro-habitats is paramount for their conservation.

Reproduction and dispersal in an ant‐associated root aphid community

Clonal organisms with occasional sex are important for our general understanding of the costs and benefits that maintain sexual reproduction. Cyclically parthenogenetic aphids are highly variable in their frequency of sexual reproduction. However, studies have mostly focused on free-living aphids above ground, whereas dispersal constraints and dependence on ant-tending may differentially affect the costs and benefits of sex in subterranean aphids. Here, we studied reproductive mode and dispersal in a community of root aphids that are obligately associated with the ant Lasius flavus. We assessed the genetic population structure of four species (Geoica utricularia, Tetraneura ulmi, Forda marginata and Forda formicaria) in a Dutch population and found that all species reproduce predominantly if not exclusively asexually, so that populations consist of multiple clonal lineages. We show that population viscosity is high and winged aphids rare, consistent with infrequent horizontal transmission between ant host colonies. The absence of the primary host shrub (Pistacia) may explain the absence of sex in three of the studied species, but elm trees (Ulmus) that are primary hosts of the fourth species (T.ulmi) occurred within a few km of the study population. We discuss the extent to which obligate ant-tending and absence of primary hosts may have affected selection for permanent parthenogenesis, and we highlight the need for further study of these aphids in Southern Europe where primary hosts may occur close to L.flavus populations, so that all four root aphid species would have realistic opportunities for completing their sexual life cycle.

Multicolonial population structure and nestmate recognition in an extremely dense population of the European ant Lasius flavus

Under optimal ecological conditions ant populations can reach high nest densities, leading to strong competition between colonies and affecting ant behaviour and sociogenetic structure. Extremely high population densities are commonly found in invasive ant species in which all colonies of a population act as a single super-colony with no behavioural or genetic boundaries between nests. In contrast, the typical and ancestral ant population structure consists of discrete genetic units, i.e. colonies with a single or few queens and highly related workers. The subterranean mound building ant Lasius flavus, which is native to Central Europe, reaches nest densities of up to 0.5 colonies per m2 in our study population in Southern Germany. We investigated the sociogenetic structure and its temporal stability in this dense population using genomic microsatellites. Despite close proximity, neighbouring nests were generally genetically distinct. Most mounds were inhabited by a single colony, but we also found a few polydomous colonies spreading over two or more mounds. About half of all colonies were monogynous, the others either polygynous and/or polyandrous. We re-sampled mounds after 8 months and found mound occupancy to be predominantly stable over time. Behavioural experiments revealed low aggression between workers from different nests, albeit these ants recognised their nestmates. Our study demonstrates that native ant species can reach high densities despite a multi-colonial population structure and that intense competition does not invariably lead to high aggression between nests.

Characterisation and cross-amplification of polymorphic microsatellite loci in ant-associated root-aphids

Twenty-six polymorphic microsatellite loci were developed for four species of ant-associated root-aphids: Geoica utricularia, Forda marginata, Tetraneura ulmi and Anoecia corni. We found up to 9 alleles per locus, with an average of 4.8. We also report polymorphic cross-amplification of eleven of these markers between different pairs of study species. Furthermore, we tested previously published aphid microsatellites and found one locus developed for Pemphigus bursarius to be polymorphic in G. utricularia. These microsatellite markers will be useful to study the population structure of aphids associated with the ant Lasius flavus and possibly other ants. Such studies are relevant because: 1. L. flavus mounds and their associated flora and fauna are often key components in protected temperate grasslands, and 2. L. flavus and its diverse community of root-aphids provide an interesting model system for studying the long-term stability of mutualistic interactions.

Soil engineering ants increase grass root arbuscular mycorrhizal colonization

The role of edaphic factors in driving the relationship between plant community structure and ecosystem processes is a key issue of the current debate on functional implications of biodiversity. In this study, we draw a direct link between aboveground/belowground relationships, vegetation structure, and aboveground management. We used ground nesting ants and arbuscular mycorrhizal fungi (AMF) as an example for quantifying the role of biotic interactions in soil. Although both groups are known to have a major impact on grasslands, the interactive effect of these taxa on vegetation structure and its sensitivity to grassland management is poorly understood. We show that the ant Lasius flavus increases the root arbuscular mycorrhizal colonization (AMC) of grasses by modifying biotic and abiotic soil properties. As a possible consequence, the shoot length of grass growing on ant mounds was shorter and shoot N and P concentrations were higher than in grass growing off of the mounds. In addition, management affected ant nest architecture and soil and, in turn, AMC. These results emphasize the need to consider the interactions between plants, soil microorganisms, soil fauna, and aboveground management to increase the understanding of the drivers of biodiversity and ecosystem functioning in grasslands both aboveground and belowground.

Population dynamics of annuals in perennial grassland controlled by ants and environmental stochasticity

AbstractQuestions:In a system of five annual plant species restricted to nest‐mounds of the antLasiusflavusin a perennial grassland: 1. Are the population dynamics influenced by ant disturbance? 2. Is the survival of the annuals at the scale of the whole grassland possible under the observed conditions of disturbance dynamics? 3. Which phases in the annuals’ life cycle and patch types contribute most to population growth?Location:Borec hill, northern Czechia, 50°31’ N, 13°59’ E, 446 m a.s.l.Methods:Local population dynamics of the annuals were analysed separately for five patch types that differed in the proportion of bare soil. Vitality rates were assessed directly in the field, but also in a garden experiment, during 2000–2001 and 2001–2002. Population dynamics at the scale of the whole grassland was analysed with a megamatrix approach, combining patch dynamics of the nest‐mounds with patch‐specific population dynamics. Contributions of different phases and patch types to growth rate were estimated by elasticity analysis.Results:Nest‐mounds differed in the percentage of bare soil. Increasing moss cover significantly reduced germination and seed production of all studied annuals and decreased their population growth rates (λ). Although successional processes dominated over ant disturbance, populations of all species could survive well (λ≫ 1) in the grassland according to the 2000–2001 megamatrix dynamics. Based on the dynamics from the following period, two species would not survive in a long‐term perspective due to random environmental variation. Whereas the A‐A transition (adult plants originating from adults of the previous year) had the highest elasticity under open conditions and ‘good period’ demography, the importance of persistent seeds increased under reverse conditions. This, however, differed among species.Conclusions:Ant‐disturbance was shown to be critical for the population survival of five annual species in the studied grassland. The fate of the annual populations in the grassland system also depends on random environmental variation, which may override the effect of ant activity.

Population dynamics of annuals in perennial grassland controlled by ants and environmental stochasticity

Questions: In a system of five annual plant species restricted to nest-mounds of the ant Lasius flavus in a perennial grassland: 1. Are the population dynamics influenced by ant disturbance? 2. Is the survival of the annuals at the scale of the whole grassland possible under the observed conditions of disturbance dynamics? 3. Which phases in the annualsʼ life cycle and patch types contribute most to population growth? Location: Borec hill, northern Czechia, 50°31' N, 13°59' E, 446 m a.s.l. Methods: Local population dynamics of the annuals were analysed separately for five patch types that differed in the proportion of bare soil. Vitality rates were assessed directly in the field, but also in a garden experiment, during 2000-2001 and 2001-2002. Population dynamics at the scale of the whole grassland was analysed with a megamatrix approach, combining patch dynamics of the nest-mounds with patch-specific population dynamics. Contributions of different phases and patch types to growth rate were estimated by elasticity analysis. Results: Nest-mounds differed in the percentage of bare soil. Increasing moss cover significantly reduced germination and seed production of all studied annuals and decreased their population growth rates (λ). Although successional processes dominated over ant disturbance, populations of all species could survive well (λ >> 1) in the grassland according to the 20002001 megamatrix dynamics. Based on the dynamics from the following period, two species would not survive in a long-term perspective due to random environmental variation. Whereas the A-A transition (adult plants originating from adults of the previous year) had the highest elasticity under open conditions and ʻgood periodʼ demography, the importance of persistent seeds increased under reverse conditions. This, however, differed among species. Conclusions: Ant-disturbance was shown to be critical for the population survival of five annual species in the studied grassland. The fate of the annual populations in the grassland system also depends on random environmental variation, which may override the effect of ant activity.

The ant Lasius flavus alters the viable seed bank in pastures

The creation of small-scale vegetation mosaics by mound building is an important aspect of ant activity in grasslands. The consequences of this process for the composition of the viable soil seed bank are poorly understood. In this study we quantified the impact of the yellow ant Lasius flavus on both aboveground vegetation and seed bank of a low-intensity pasture located in the Vogelsberg area (Hesse, Germany). A few species of the mound vegetation (mainly therophytes) were restricted to the mounds, but most species also occurred in the surrounding area. The seed bank of ant mounds differed from that of the pasture soil between the mounds, with the abundance of germinating seeds being twice as high in the mounds. This was mainly due to the very large number of seeds originating from winter annuals and Thymus pulegioides. Seed abundance of most other species was lower in the mounds. Our results showed that this is partly due to dispersule weight limiting dispersal of seeds from the surrounding vegetation onto the mounds.

Social structure in the ant Lasius flavus: multi‐queen nests or multi‐nest mounds?

Abstract. The yellow subterranean ant Lasius flavus is generally considered to have a single queen in mature nests. Yet, many anecdotal observations have suggested that the conspicuous earth mounds of this ant may, at least occasionally, contain several queens and their offspring. To estimate the number of matrilines per mound, samples for horizontal starch gel electrophoresis were collected from a total of thirty‐seven mounds in three sites of old chalk‐grassland in southern England. Allozymatic variation at an esterase and hexokinase locus showed that probably more than 50% of the mounds contained more than one queen and that the mean number of queens per mound is at least 1.5–2. Further results strongly suggested that workers from different matrilines may share the same galleries, at least in the top of the mound. The apparently variable social structure of Lasius flavus colonies is discussed, both technically and with reference to ecological processes related to the presence of ants in the nest mounds.

Studies on the relationship between the ant ectoparasiteAntennophorus grandis(Acarina: Antennophoridae) and its hostLasius flavus(Hymenoptera: Formicidae)

The mite Antennophorus grandis (Berlese, 1903) is a large obligate ectoparasite of workers of the ant Lasius flavus(Fabricius). It rides under the head of the ants and uses its long front legs to communicate with its hosts and stimulate them to give it food. We present allometric and morphometric data showing that L. flavus workers can occur in two size classes. We also present the first quantitative ethograms of mite-bearing and mite-free L. flavus workers of the two size categories. The mites tend to occur on the smaller nurse workers and receive food from them at an extremely high frequency. Antennophorus grandis also frequently gain food when one ant is donating food to the one they are riding upon. The mites seem to inhibit the ability of their host worker to show most social behaviours such as tending ant larvae. The mites frequently move from one host worker to another. For these reasons the mites may have a larger impact upon their host colony than their relative rarity first suggests. The ants do not seem to have any specific defence against these parasites. The mites live in small populations and show female-biased sex ratios consistent with local mate competition. Preliminary evidence suggests that the mites have haplodiploid sex determination which may explain how they are able to adapt their sex allocation to their population size.

The growth and development of the overwintering larvae in the ant Lasius flavus (Hymenoptera: Formicidae)

The growth and development of the larvae of the ant Lasius flavus (F.) have been traced from the autumn to the following summer. The changes in fresh weight, dry weight, protein content and food reserves in the form of fats and carbohydrates are given. The course of development of the larvae is discussed in relation to the production of queens, workers and males.

Ontogenesis of the defence reactions in the workers of Myrmica rubra L. (Hymenoptera: Formicidae)

Differently pigmented workers of Myrmica rubra societies were observed when stimulated by the ant Lasius flavus. They showed different reactions primarily according to their age. The oldest ants of pigmentary group 5 mostly attacked the enemy while younger ones of categories 4 and 3 spent more time in recruiting congeners. The youngest workers took no part in defending the colony against an intruder.

Further Considerations of Competition and the Ecology of the Ants Lasius flavus (F.) and L. niger (L.)

In earlier papers (Pontin 1957, 1960, 1961a, b; Odum & Pontin 1961) work on populations of these ants in 1956-58 was described and the following account is of population changes observed after a lapse of 5 years and discussion of some aspects not previously covered. It is convenient to divide the paper into two parts. The first deals with the history of the populations from early colonization to eventual extinction, and the second deals with stabilization of mature populations where plant succession has been checked at a suitable stage.

The effect of the number of queens of the antLasius flavus (Fab.) (Hym., Formicidae) on their survival and on the rate of development of the first brood

Populous colonies ofLasius flavus F. are generally haplometrotic, yet not infrequently several queens combine in founding nests. This aggregation after flight is not always accidental, but may arise from cooperation between the females in the digging of new burrows. Probably the queens become habituated to one another at this stage. In the laboratory the multi-female colonies were at an advantage over the single female ones, as the mortality of the queens was reduced and the first brood of workers was reared more rapidly. Grouping of the queens ofL. flavus and of those ofL. niger did not appear to influence the ovarial development of the survivors, and they all contributed to the establishment and the rearing of the first brood. This pleometrosis was temporary and the multi-queen colonies began to split into smaller units at the time of the appearance of the earliest pupae. InL. niger, fighting to death between the queens, at times of repeated ovipositions, also contributed towards the final state of haplometrosis.

The Effect of Gravity on the Oscillations in the Path of an Ant (Lasius Flavus NearticusWheeler): A Study of Random Movements

The Effect of Gravity on the Oscillations in the Path of an Ant (<i>Lasius Flavus Nearticus</i>Wheeler): A Study of Random Movements