Wood Ants Research Articles

Level locomotion in wood ants: evidence for grounded running

In order to better understand the strategies of locomotion in small insects, we have studied continuous level locomotion of the wood ant species Formica polyctena. We determined the three-dimensional centre of mass kinematics during the gait cycle and recorded the ground reaction forces of single legs utilising a self-developed test site. Our findings show that the animals used the same gait dynamics across a wide speed range without dissolving the tripodal stride pattern. To achieve higher velocities, the ants proportionally increased stride length and stepping frequency. The centre of mass energetics indicated a bouncing gait, in which horizontal kinetic and gravitational potential energy fluctuated in close phase. We determined a high degree of compliance especially in the front legs, as the effective leg length was nearly halved during the contact phase. This leads to only small vertical oscillations of the body, which are important in maintaining ground contact. Bouncing gaits without aerial phases seem to be a common strategy in small runners and can be sufficiently described by the bipedal spring-loaded inverted pendulum model. Thus, with our results, we provide evidence that wood ants perform 'grounded running'.

Contribution of ant and microbial respiration to CO2 emission from wood ant (Formica polyctena) nests

As ecosystem engineers, wood ants (Formica s. str.) influence many processes in forest ecosystems. Their nests are “hot spots” for CO2 production, and some nests are relatively wet (>35% moisture content) while others are dry (<20% moisture content). In this study, we compared CO2 production, the contribution of ant and nest material respiration to the overall CO2 production, and the rate of decomposition in dry vs. wet nests of wood ants (Formica polyctena). We also determined whether ants increase microbial respiration in nest material. Respiration in ant nests was higher than in the surrounding soil and was higher in wet nests than in dry nests. Ant contribution to the overall respiration was significantly higher than that of nest material respiration: the average ratio of the contributions (ants:nest material) was 75:25%. Litter mass loss (determined with litter bags buried in the nests) was significantly higher in wet nests than in dry nests. In a laboratory experiment, respiration was significantly higher with the combination of nest material and ants (provided with honey) than with the sum of respiration with nest material and ants (provided with honey) kept separately. This indicates that ants stimulate microbial respiration, most likely because they incorporate honey solution into the nest material.

Differences in nest structure influence the importance of Formica rufa group (Hymenoptera: Formicidae) wood ant nests as refugia for earthworms

A previous study on the nests of the wood ant species Formica aquilonia in Finland showed them to be summer refugia for two species of earthworms in Finland. They showed that earthworm abundance and biomass were greater in nests than in surrounding soil and leaf litter, emphasizing the importance of the ants as ecosystem engineers. In this study nests of the closely related wood ant, Formica rufa in southern England were sampled to investigate whether earthworms use the nests in a similar way. Few earthworms were found in the wood ant nests sampled. The reason for these differences was probably because F. rufa nest structure was dry and lacked the moist decomposing layer found in the nests of F. aquilonia. We conclude that F. rufa nests are not used by earthworms as summer refugia in southern England. This re-emphasizes the difficulties of generalizing across closely related taxa and within biogeographical regions.

Proximity to the forest edge affects the production of sexual offspring and colony survival in the red wood ant Formica aquilonia in forest clear-cuts

Red wood ants of the Formica rufa group, as well as their nests, form a vital part of the ecosystems of both European and Siberian boreal and temperate forests. It has been well documented that the nests of red wood ants in clear-cuts do not perform as well as those deeper in the forest. However, clear-cuts may not be a homogeneously poor habitat for such forest-dwelling ants because the distance of the nest site to the edge of the remaining forest may be a significant factor affecting the nest performance. In this study, I compared the probability of nest survival and sexual offspring production between the nests of Formica aquilonia (Yarrow, 1955) in a forest edge zone (distance to the forest edge <9.2 m) and a clear-cut centre zone in 18 different clear-cut areas. Although the nests were generally smaller, the probability of sexual offspring production and nest survival was higher among those nests in the edge compared to the centre zone. Since the proximity to the forest edge increased the performance of a nest, selective logging and smaller scale clear-cuts may not be as harmful to red wood ants as clear-cutting over a large area.

Catalog Learning: Carabid Beetles Learn to Manipulate with Innate Coherent Behavioral Patterns

One of the most fascinating problems in comparative psychology is how learning contributes to solving specific functional problems in animal life, and which forms of learning our species shares with non-human animals. Simulating a natural situation of territorial conflicts between predatory carabids and red wood ants in field and laboratory experiments, we have revealed a relatively simple and quite natural form of learning that has been overlooked. We call it catalog learning, the name we give to the ability of animals to establish associations between stimuli and coherent behavioral patterns (patterns consist of elementary motor acts that have a fixed order). Instead of budgeting their motor acts gradually, from chaotic to rational sequences in order to learn something new, which is characteristic for a conditioning response, animals seem to be “cataloguing” their repertoire of innate coherent behavioral patterns in order to optimize their response to a certain repetitive event. This form of learning can be described as “stimulus-pattern” learning. In our experiments four “wild” carabid species, whose cognitive abilities have never been studied before, modified their behavior in a rather natural manner in order to avoid damage from aggressive ants. Beetles learned to select the relevant coherent behavioral patterns from the set of seven patterns, which are common to all four species and apparently innate. We suggest that this form of learning differs from the known forms of associative learning, and speculate that it is quite universal and can be present in a wide variety of species, both invertebrate and vertebrate. This study suggests a new link between the concepts of cognition and innateness.

A comparison of mark–release–recapture methods for estimating colony size in the wood ant Formica lugubris

Colony size can be considered the analogue of the body size of a superorganism. Just as body size is important to the physiology of an individual animal, colony size correlates with the life-history and ecology of social insects. Although nest excavation and counting all individuals is the most accurate method for estimating colony size (or nest size), it has the major drawback of being destructive. Alternatively, mark–release–recapture (MRR) can be used repeatedly to measure the size of the same colony or nest. We compared the accuracy and feasibility of four MRR methods and a Mound-Volume method with complete counts from nest excavation for estimating the nest size of F. lugubris, a mound-building wood ant of the Formica rufa group, during the early spring in Scotland. We found that our After-Disturbing method, in which we performed marking and recapturing after gentle disturbance to the top of nest mound, has the best balance between accuracy, non-destructiveness, and time required. We also found that mound volume can be an index of ant nest size under certain conditions. Both non-destructive methods can be used on the same colony or nest repeatedly to monitor nest dynamics.

GeoBioScience: Red Wood Ants as Bioindicators for Active Tectonic Fault Systems in the West Eifel (Germany).

Simple SummaryIn a 1.140 km² study area of the volcanic West Eifel, approx. 3,000 Red Wood Ant (RWA; Formica rufa-group) mounds had been identified and correlated with tectonically active gas-permeable faults, mostly strike-slip faults. Linear alignment of RWA mounds and soil gas anomalies distinctly indicate the course of these faults, while clusters of mounds indicate crosscut zones of fault systems, which can be correlated with voids caused by crustal block rotation. This demonstrates that RWA are bioindicators for identifying active fault systems and useful where information on the active regime is incomplete or the resolution by technical means is insufficient.In a 1.140 km² study area of the volcanic West Eifel, a comprehensive investigation established the correlation between red wood ant mound (RWA; Formica rufa-group) sites and active tectonic faults. The current stress field with a NW-SE-trending main stress direction opens pathways for geogenic gases and potential magmas following the same orientation. At the same time, Variscan and Mesozoic fault zones are reactivated. The results showed linear alignments and clusters of approx. 3,000 RWA mounds. While linear mound distribution correlate with strike-slip fault systems documented by quartz and ore veins and fault planes with slickensides, the clusters represent crosscut zones of dominant fault systems. Latter can be correlated with voids caused by crustal block rotation. Gas analyses from soil air, mineral springs and mofettes (CO2, Helium, Radon and H2S) reveal limiting concentrations for the spatial distribution of mounds and colonization. Striking is further the almost complete absence of RWA mounds in the core area of the Quaternary volcanic field. A possible cause can be found in occasionally occurring H2S in the fault systems, which is toxic at miniscule concentrations to the ants. Viewed overall, there is a strong relationship between RWA mounds and active tectonics in the West Eifel.

TRAIL-FOLLOWING RESPONSES OF THE RED WOOD ANT FORMICA RUFA L. IN DARKNESS

ABSTRACT The responses of the red wood ant, Formica rufa, to an artificial trail were examined in darkness in a controlled laboratory environment using a satiated colony. Artificial trails were prepared in four different solvents from the head, thorax+legs, and gaster extracts of foragers. Thorax+legs extracts did not elicit directional responses in foragers. Gaster extracts were consistently followed, suggesting that trail-following is induced by pheromones issued from gastric glands. Head extracts were also followed, but foragers displayed excitement, most probably in response to an alarm message.

Interference competition, not predation, explains the negative association between wood ants (Formica rufa) and abundance of ground beetles (Coleoptera: Carabidae)

Intraguild interactions between predators have significant implications for how multiple predators impact on their prey. Carabid assemblages are not generally thought to be structured by interspecific competitive interactions, species relative abundances instead being determined mainly by abiotic factors. However, several field studies report negative associations between the abundance of certain carabid species and the presence of wood ants. Replicated laboratory experiments were used to monitor the behaviour of individual female Abax parallelepipedus (Piller &amp; Mitterpacher) in the presence of a range of wood ant (Formica rufa L.) densities (including ant‐free controls) over 23 h. Carabids did not feed when wood ants were present. Running and defence activities were high at low ant densities but decreased with increasing ant density. At the highest ant density, all carabids were killed within the first 2 h of the experiment, but the ants did not consume the carabids after they had killed them. Carabid diurnal activity increased at the higher wood ant densities. Female A. parallelepipedus and Pterostichus madidus (F.) maintained individually in the presence of five wood ants had significantly lower mean body weights and carried fewer eggs after 21 days compared to control beetles that had been kept without ants. The results help to explain the reduced abundance of these two carabid species under field conditions when wood ants are present. We interpret these findings to mean that the interaction between wood ants and carabids is one of asymmetric aggressive interference competition rather than predation.

Visual Scene Perception in Navigating Wood Ants

Ants, like honeybees, can set their travel direction along foraging routes using just the surrounding visual panorama. This ability gives us a way to explore how visual scenes are perceived. By training wood ants to follow a path in an artificial scene and then examining their path within transformed scenes, we identify several perceptual operations that contribute to the ants' choice of direction. The first is a novel extension to the known ability of insects to compute the "center of mass" of large shapes: ants learn a desired heading toward a point on a distant shape as the proportion of the shape that lies to the left and right of the aiming point--the 'fractional position of mass' (FPM). The second operation, the extraction of local visual features like oriented edges, is familiar from studies of shape perception. Ants may use such features for guidance by keeping them in desired retinal locations. Third, ants exhibit segmentation. They compute the learned FPM over the whole of a simple scene, but over a segmented region of a complex scene. We suggest how the three operations may combine to provide efficient directional guidance.

Early Results of Three-Year Monitoring of Red Wood Ants' Behavioral Changes and Their Possible Correlation with Earthquake Events.

Simple SummaryFor three years (2009–2012), two red wood ant mounds (Formica rufa-group), located at the seismically active Neuwied Basin (Eifel, Germany), have been monitored 24/7 by high-resolution cameras. Early results show that ants have a well-identifiable standard daily routine. Correlation with local seismic events suggests changes in the ants’ behavior hours before the earthquake: the nocturnal rest phase and daily activity are suppressed, and standard daily routine does not resume until the next day. At present, an automated image evaluation routine is being applied to the video streams. Based on this automated approach, a statistical analysis of the ant behavior will be carried out. Short-term earthquake predictions with an advance warning of several hours or days are currently not possible due to both incomplete understanding of the complex tectonic processes and inadequate observations. Abnormal animal behaviors before earthquakes have been reported previously, but create problems in monitoring and reliability. The situation is different with red wood ants (RWA; Formica rufa-group (Hymenoptera: Formicidae)). They have stationary mounds on tectonically active, gas-bearing fault systems. These faults may be potential earthquake areas. For three years (2009–2012), two red wood ant mounds (Formica rufa-group), located at the seismically active Neuwied Basin (Eifel, Germany), have been monitored 24/7 by high-resolution cameras with both a color and an infrared sensor. Early results show that ants have a well-identifiable standard daily routine. Correlation with local seismic events suggests changes in the ants’ behavior hours before the earthquake: the nocturnal rest phase and daily activity are suppressed, and standard daily routine does not resume until the next day. At present, an automated image evaluation routine is being applied to the more than 45,000 hours of video streams. Based on this automated approach, a statistical analysis of the ants’ behavior will be carried out. In addition, other parameters (climate, geotectonic and biological), which may influence behavior, will be included in the analysis.

Learning to forage: the learning walks of Australian jack jumper ants

Event Abstract Back to Event Learning to forage: the learning walks of Australian jack jumper ants Piyankarie Jayatilaka1*, Chloé Raderschall1, Jochen Zeil1 and Ajay Narendra1 1 The Australian National University, ARC Centre of Excellence in Vision Science, The Research School of Biology, Australia The ‘jack jumper’ ants, Myrmecia croslandi travel as far as 15m from the nest to find food. Being solitary and highly visual foragers, these ants navigate remarkably well without the help of recruitment and pheromone trails, relying solely on their individual navigational abilities. However, any inexperienced, solitary forager leaving the nest for the first time needs to acquire these abilities. We individually marked all foragers of two nests of M. croslandi and tracked their movements around the nest with video and throughout their foraging journeys with Differential GPS. When inexperienced ants leave the nest for the first time, they perform ‘learning walks’ as have been previously described for desert and wood ants. These walks are different from other forager behaviours and can be clearly identified by the following characteristics. (1) Learning walks are short, round trips that occur in different directions within 1m of the nest. (2) A single ant may carry out several walks throughout the day before it leaves the nest to forage. (3) With time, the area around the nest covered by these learning walks increases. (4) During learning walks ants look around extensively but rarely look back at the nest. Here, I will discuss consistent patterns between learning view directions and the first foraging trip. I will show how individuals perform learning walks in specific directions around the nest, mostly in the initial foraging direction and in the opposite direction. I will also highlight how in some cases learning walks may be repeated by ants that (a) change initial foraging directions or (b) by ants that have had great difficulty in locating the nest on their previous trip. Figure 1 Keywords: Ants, navigation, foraging, learning walks, solitary Conference: International Conference on Invertebrate Vision, Fjälkinge, Sweden, 1 Aug - 8 Aug, 2013. Presentation Type: Poster presentation preferred Topic: Navigation and orientation Citation: Jayatilaka P, Raderschall C, Zeil J and Narendra A (2019). Learning to forage: the learning walks of Australian jack jumper ants. Front. Physiol. Conference Abstract: International Conference on Invertebrate Vision. doi: 10.3389/conf.fphys.2013.25.00081 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 23 Apr 2013; Published Online: 09 Dec 2019. * Correspondence: Ms. Piyankarie Jayatilaka, The Australian National University, ARC Centre of Excellence in Vision Science, The Research School of Biology, Canberra, ACT, 0200, Australia, piyankarie@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Piyankarie Jayatilaka Chloé Raderschall Jochen Zeil Ajay Narendra Google Piyankarie Jayatilaka Chloé Raderschall Jochen Zeil Ajay Narendra Google Scholar Piyankarie Jayatilaka Chloé Raderschall Jochen Zeil Ajay Narendra PubMed Piyankarie Jayatilaka Chloé Raderschall Jochen Zeil Ajay Narendra Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Ants protect conifer seedlings from feeding damage by the pine weevil Hylobius abietis

Ants that protect food resources on plants may prey on (or deter) herbivores and thereby reduce damage. Red wood ants (of the Formica rufa group) are dominant ants in boreal forests of Eurasia and affect the local abundance of several herbivorous species. The pine weevil Hylobius abietis (L.) is a herbivore that causes severe damage by feeding on the bark of coniferous seedlings within areas of forest regeneration. We investigated whether ants can protect conifer seedlings from pine weevil feeding. In a manipulative experiment, ants were attracted to sugar baits attached to spruce seedlings and the damage caused by pine weevils was compared with control seedlings without ant‐baits. The feeding‐scar area was approximately one‐third lower on the seedlings with ant‐baits compared with the controls. Besides red wood ants, Myrmica ants were also attracted in high numbers to the ant baits and the relative effects of these species are discussed. The results obtained in the present study support the trophic cascade hypothesis (i.e. damage to herbivores is suppressed in the presence of predators). The decreased pine weevil feeding on the baited seedlings was probably a result of nonconsumptive interactions [i.e. the presence of (or harassment by) ants distracting pine weevils from feeding]. Understanding the role of ants may have important implications for future strategies aiming to control pine weevil damage. For example, maintaining suitable conditions for ants after harvesting stands may be an environmentally friendly but currently unexploited method of for decreasing weevil damage.

The Role of Wood Ants (Formica rufa group) in Carbon and Nutrient Dynamics of a Boreal Norway Spruce Forest Ecosystem

Wood ants (Formica rufa group) are regarded as keystone species in boreal and mountain forests of Europe and Asia by their effect on ecosystem carbon (C) and nutrient pools and fluxes. To quantify the impact of their activity on boreal forest ecosystems, C, nitrogen (N), phosphorus (P), potassium (K) and calcium (Ca) pools and fluxes in wood ant nests (WAN), and soil were assessed along a 5-, 30-, 60-, and 100-year-old Norway spruce (Picea abies L. Karsten) dominated successional gradient in eastern Finland. Amounts of C and nutrients in WAN increased with stand age, but contained less than 1% of total C and nutrient pools in these stands. The CO2-efflux from nests was also insignificant, as compared to CO2-efflux from the forest floor. Annually, the amount of C brought by wood ants into their nests as honeydew, prey and nest-building materials ranged from 2.7 to 49.3 kg ha−1 C, but this is only 0.1–0.7% of the combined net primary production of trees and understorey in boreal forests. The difference between wood ant nest C inputs and outputs was very small in the younger-aged stands, and increased in the older stands. Carbon accumulation rates in nests over a 100 year period are estimated to be less than 10 kg ha−1 a−1. In contrast to C, annual inputs of N, P, and K are larger compared to wood ant nest nutrient pool size, ranging from 3 to 6% of the annual tree stand and understorey uptake. This indicates a more rapid turnover and transport of N, P, and K out of WAN, and suggests that wood ants increase the cycling rate of these nutrients in boreal forests.

First record of an indoor pest sawtoothed grain beetle &lt;i&gt;Oryzaephilus surinamensis&lt;/i&gt; (Coleoptera: Silvanidae) from wild outdoor wood ant nest

Alive individual adult sawtoothed grain beetle Oryzaephilus surinamensis (Linnaeus, 1758) was discovered inside a nest mound of the red wood ant Formica rufa Linnaeus, 1758 during a survey of myrmecophilous invertebrates. The sawtoothed grain beetle is a widespread indoor pest that has not previously been found in an ant nest. It is one of the most common pests in stored grain and cereal products, but the natural life-style of the species is not known. As the site of discovery was exceptional, we verified the species identification using the DNA barcode. If the sawtoothed grain beetle can live in mounds of red wood ants, the mounds may become widespread source habitats for the future infestations of this serious stored product pest.

Fourmis des bois en Suisse: état de la situation et perspectives de monitoring

Wood ants in Switzerland: situation and outlook of a monitoring The authors summarise their state of knowledge about wood ants and their role in the forest ecosystem. They also describe the situation in Switzerland, their past development and their conservation status. In several regions, mainly in the Plateau, wood ants seem to diminish, despite their total protection since 1966. The reasons for this regression are not well known, but the fragmentation of forest habitats in the Plateau region and direct damage to ant nests seem to play a certain role. A new project in which the development of wood ant nests is monitored in Swiss forest reserves (Formica-Forêts-CH) was recently started in the Swiss national park. It is to be extended, in collaboration with the forest services, over the whole of Switzerland.

The effect of stand age on CO2 efflux from wood ant (Formica rufa group) mounds in boreal forests

Recent studies suggest that wood ants (Formica rufa group) mounds are point sources of carbon dioxide (CO2), which increase the heterogeneity of soil carbon (C) emissions in forest ecosystems. However, little is known about the impact of anthropogenic activities, such as logging and subsequent forest succession, on these fluxes. In this study, we measured the CO2 efflux and temperature of wood ant mounds and the surrounding forest floor in managed Finnish boreal forests of different ages (5, 30, 60, and 100 years old) to assess how the effluxes vary with stand age. We conducted efflux measurements from the mounds and the surrounding forest floor throughout the ants' active season (May–September) and during the onset of hibernation (October). The annual CO2 efflux was then estimated using mound or forest floor temperatures, which were measured for one year. The average annual CO2 efflux from the ant mounds was 10.2 (±5.8 SD) kg m−2 year−1, increasing from 3.9 (±0.3 SD) kg m−2 year−1 in the 5 year-old stands to 14.3 (±3.0 SD) kg m−2 year−1 in the 100 year-old stands. Temperatures was significantly higher in the ant mounds than in the forest floor, and the average temperature difference between mounds and forest floor increased with stand age, being the lowest in the 5 year-old (4.1 (±3.1 SD) °C) and highest in the 100 year-old stands (10.3 (±5.2 SD) °C). There were no statistical differences in the mound CO2 efflux per volume among forest age classes, suggesting higher ant CO2 efflux in the older stands likely come from larger ant populations in the bigger mounts. The different mound temperature regimes among stand age classes indicates that the activity of wood ants changes with forest succession, particularly after clear-cutting, which alters CO2 efflux from the mounds. The impact of ant mounds on total CO2 efflux from the soil, estimated from mound area and volume, respectively, increased with forest age, from 0.05 (±0.05 SD) % to 0.31 (±0.18 SD) % and from 0.05 (±0.06 SD) % to 0.90% (±1.11 SD).

Antiparasite behavior

Antiparasite behavior

Asymmetry in antennal contacts during trophallaxis in ants

Behavioural and brain left–right asymmetries are a common feature among the animal kingdom. Lateralization often manifests itself at the population-level with most individuals showing the same direction of lateral bias. Theoretical model based on evolutionary stable strategy predicts that lateralization at the population-level is more likely to characterize social rather than solitary species. Empirical data supporting this hypothesis has been recently obtained in Hymenoptera showing that eusocial honeybees present an asymmetrical use of the antennae: the right antenna is involved in olfactory learning and present more olfactory receptors. However, no evidences about the role of antennal asymmetries in social interactions have been provided so far. Highly social ant species belonging to Formica rufa group are a good model for investigating natural communication because they are able to pass exact information to their nest mates. We applied the “binary tree” experimental paradigm, which allowed us to observe different types of antennal contacts performed by ants out of their nest. To examine possible asymmetrical use of the right and left antenna, we focused on “feeding” (the simplest) contacts where a “donor” ant is exchanging food with a “receiver” ant through trophallaxis. We observed a population-level asymmetry, with the “receiver” ant using the right antenna significantly more often than the left antenna. This study provides the first evidence of lateralization in antennal contacts in ants, and seems to support the hypothesis of mathematical models on the evolution of lateralization suggesting that the alignment of lateralization at the population-level matters in social interactions.

Stand type is more important than red wood ant abundance for the structure of ground-dwelling arthropod assemblages in managed boreal forests

1 The relationships between red wood ants (Formica rufa group) and other ground-dwelling arthropods were studied in young managed forests stands in Eastern Finland. The main objectives were: (i) to test the influence of stand type (dominant tree species; age: sapling versus pole stage) and numbers of red wood ants on the occurrence of other ground-dwelling arthropods and (ii) to study the occurrence of red wood ants versus other arthropods on a distance gradient from ant mounds. We used pitfall traps set in 5–14-year-old sapling stands and 30–45-year-old pole-stage stands of Scots pine (Pinus sylvestris L.) and birch (Betula spp.) forests. 2 Pitfall trap catches of red wood ants did not vary significantly between the forest stand types, although some groups of other arthropods showed clear responses to stand type (e.g. catches of other Formicinae and Gnaphosidae were higher in sapling stands than in pole-stage stands). The number of red wood ants clearly explained less of the variation in assemblages of other ground-dwelling arthropods than the forest stand type. 3 Red wood ant numbers decreased significantly with distance from the mounds, but the other ground-dwelling arthropods were insensitive to this gradient or even showed a preference for proximity to ant mounds and high ant activity. 4 The results obtained in the present study suggest that wood ants do not have strong effects on several other ground-dwelling arthropod groups in young managed forests other than in the immediate vicinity of their mounds.