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Ant communities are structured, in part, by competition between related and unrelated ant species for territories and food resources. In eastern deciduous forests of the United States, a single ant genus (Aphaenogaster) appears ecologically dominant with high abundance and opportunistic foraging. However, Aphaenogaster ants are not particularly behaviorally aggressive toward co-occurring ants, making it unclear as to how they might sustain dominance. We offered myrmecochorous seeds and termite carrion at bait stations and quantified ant aggression, food selection and recruitment. We conducted the experiments throughout the natural seed-release window to determine how the abundance of low- and high-quality food items impacted behavior. We found evidence that Aphaenogaster ants dominate the retrieval of both seeds and insect carrion (dead termites). Aphaenogaster foraging dominance did not appear driven by superior fighting or recruitment abilities but simply by having more foragers on the ground, essentially achieving control of different types of food resources through numerical dominance. Moreover, though they are the dominant effective seed dispersers in the system, A. picea exhibited a much greater affinity for termites than seeds, and the desirability of termites decreased in the presence of seeds. Overall, our results suggest that high numbers of foragers—as opposed to aggressive territoriality—can be an effective ecological strategy for sustaining ecological dominance through resource acquisition.

The twin flagged jumping spider, Anasaitis canosa (Walckenaer) (Araneae: Salticidae) is a common ant-predating spider whose diet has been quantified previously only in the laboratory. We investigated the diet of this spider species in the field, as well as approximated its abundance in the observation area. During 30 d of observation, A. canosa occurred in a density of 2.43 ± 1.35 spiders per m2 where 32 attacks were observed on a variety of invertebrate prey. These results parallel previous observations of spiders having greater success killing ant workers opposed to other invertebrates in addition to providing evidence that these spiders likely are not dietary specialists on ant prey. Sumario La arana saltarina de bandera gemela, Anasaitis canosa (Walckenaer) (Araneae: Salticidae) es una arana depredadora de hormigas comun cuya dieta se ha cuantificado previamente solo en el laboratorio. Investigamos la dieta de esta especie de arana en el campo, asi como aproximamos su abundancia en el area de observacion. Durante 30 dias de observacion, A. canosa se presento en una densidad de 2.43 ± 1.35 aranas por m2 donde se observaron 32 ataques en una variedad de presas invertebradas. Estos resultados son paralelos a las observaciones previas de aranas que tienen mas exito matando a las hormigas trabajadoras en comparacion con otros invertebrados, ademas de proporcionar evidencia de que estas aranas probablemente tienen una dieta especializada en las hormigas presas. Key Words: stenophagy; myrmecophagy; spider ecology; Florida View this article in BioOne

Standing dead trees (snags) decompose more slowly than downed dead wood and provide critical habitat for many species. The rate at which snags fall therefore influences forest carbon dynamics and biodiversity. Fall rates correlate strongly with mean annual temperature, presumably because warmer climates facilitate faster wood decomposition and hence degradation of the structural stability of standing wood. These faster decomposition rates coincide with turnover from fungal-dominated wood decomposer communities in cooler forests to codomination by fungi and termites in warmer regions. A key question for projecting forest dynamics is therefore whether temperature effects on wood decomposition arise primarily because warmer conditions facilitate faster decomposer metabolism, or are also influenced indirectly by belowground community turnover (e.g., termites exert additional influence beyond fungal-plus-bacterial mediated decomposition). To test between these possibilities, we simulate standing dead trees with untreated wooden posts and follow them in the field across 5 yr at 12 sites, before measuring buried, soil-air interface and aerial post sections to quantify wood decomposition and organism activities. High termite activities at the warmer sites are associated with rates of postfall that are three times higher than at the cooler sites. Termites primarily consume buried wood, with decomposition rates greatest where termite activities are highest. However, where higher microbial and termite activities co-occur, they appear to compensate for one another first, and then to slow decomposition rates at their highest activities, suggestive of interference competition. If the range of microbial and termite codomination of wood decomposer communities expands under climate warming, our data suggest that expansion will accelerate snag fall with consequent effects on forest carbon cycling and biodiversity in forests previously dominated by microbial decomposers.

Ants are a widespread group of ecologically important insects. Therefore, ants that are important predators of other ants are likely to play key roles by changing the abundance and impacts of their prey. Familiar arthropod predators, like army ants, are known for their overwhelming raids on invertebrate prey but are limited to mostly tropical systems. Thief ants (Genus: Solenopsis Westwood) are a cosmopolitan group of mostly subterranean ants found in a wide variety of ecosystem types. They are known for their extremely small sizes and their specialized predation where they stealthily tunnel into the nests of other larger ant species to capture and consume only immature ants (larvae and pupae). Predation of ant colonies by other ants, and specialized predatory behaviors of presumed top ant predators (e.g., army ants) are well known. However long-term predation effects, such as across several seasons, are still poorly understood because of a lack of experimental studies. Here we report results of a ~1.5-year press field experiment where thief ants were reduced in natural ant communities. Potential impacts, such as predator-release, were quantified by sampling the co-occurring ant community. Compared to control plots, overall worker abundance and biomass increased where thief ants were reduced, and effects varied among ant species. Results suggest predator release as select aboveground foraging ant species increased in abundance and that thief ants may act as significant predators. Because thief ants are abundant and widespread, similar predatory effects may occur in many ant communities, and our understanding of important predators may need to adjust to include thieving species as well as army ants. Thief ants are very abundant, tiny, specialized to consume immature life stages, equipped with powerful venom, eusocial, and subterranean. This suite of adaptive traits seems unique to eusocial predators compared to animals, where "thieving" predators are usually larger in size compared to their adult-sized prey. Future work quantifying top-down regulation of prey and cascading consumptive and non-consumptive effects will help to understand thief ant predation and potential effects on ecosystem processes.

Summary Hypotheses of community assembly include limitation through habitat physical attributes, as well as competition among species. Such hypotheses must be resolved through experimental tests. Previous experiments have shown that: (i) fire ants of the monogyne social form occur mostly in highly disturbed habitat where they do not compete with mature colonies of co-occurring ants; (ii) in native pine forests of northern Florida, habitat disturbance favours fire ants while simultaneously reducing native ants; (iii) fire ants thrive in these disturbances but do not persist as these become less disturbed over time; and finally, (iv) newly mated, dispersing/colony-founding fire ant queens settle preferentially in such disturbed sites. We now show that by choosing disturbed sites, newly mated, monogyne fire ant queens greatly increase their chances of successful colony establishment. Experimental plots were created in the native ground cover of a north Florida pine forest with all combinations of tilling, shading or reduction of the native ant community. Newly mated fire ant queens, incipient colonies and small colonies were planted in these plots. Only five of 980 (0·5%) newly mated queen nests survived after 120 days, and only five of 400 incipient colonies (1·3%) survived after 30 days. All survivors were in plots with tilling and/or native ant reduction. Extrapolation indicated that 0·04% of newly mated queens and 0·1% of incipient colonies were likely to have survived at 1 year. In contrast, planting small colonies resulted in much higher rates of survival – in plots with native ant reduction, fire ants increased on baits throughout the year but decreased in unreduced control plots. Fifteen months after planting 108 colonies, 21 mounds (19%) were found in the ant-reduced plots, but

Social insects are an obvious example of soil macrofauna whose role in soil food webs remains poorly understood. Termites and ants are among the most abundant invertebrates found in many terrestrial ecosystems. Termites are functionally detritivores while ants are functionally omnivores in most soil food webs although variation in ant feeding habits and preferences can mean that some species are functionally herbivores while others are predators. The areal abundance of termites and ants in soils, their ecosystem engineering activities in soils and dead wood, and their enormous variety of species interactions with soil organisms suggest that they are key members of soil food webs. Identifying the species of social insects present in soil food webs and quantifying their abundance by collecting whole colonies, whenever possible, will allow quantification of their areal abundance. Using manipulative experiments to test their impacts in combination with studying their areal abundance, diet, and describing the interacting species found within their functional domains (nests, galleries, gut faunae, etc.) it will be possible to better understand the impacts of social insects on soil food webs.

Exotic invasive species are one of the most widespread and common agents of change in ecosystems worldwide. Here, we are focused on community-level changes associated with the appearance and persistence of exotic species in an ecosystem over more than 2 decades. We combined datasets of Florida's ant (Hymenoptera: Formicidae) community from Wekiwa Springs State Park, Florida, USA, spanning 25 yr, which included 3 sampling events in several distinct upland ecosystems. Species accumulation curves, non-parametric species estimators, community similarity indices, and ratios of exotic to native ants were used to assess sampling effort, including patterns of diversity, and changes in community composition. Our data showed that the ant community of Wekiwa Springs has at least 4 exotic species present in all of the ecosystems sampled within the park. These upland ecosystems are accumulating exotics slowly and, with one exception, there is no clear signal that the exotic species are displacing native species. The likely exception is the invasive fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), causing local extinction of the native fire ant Solenopsis geminata (Fabricius) (Hymenoptera: Formicidae). Continued long-term monitoring efforts are necessary to understand how these exotics may impact native communities in the future.

Invasive species generally occur and thrive in human-disturbed ecosystems, but Brachyponera chinensis (Asian needle ant, formerly ‘Pachycondyla chinensis’) also invades intact forests. The invasion into native habitats potentially puts B. chinensis in direct competition with the keystone seed-dispersing ants in the genus Aphaenogaster. We observed B. chinensis colonizing artificial nests placed in deciduous forest of the north Georgia Piedmont (US). Their presence appeared to displace existing Aphaenogaster rudis and Reticulitermes flavipes (subterranean termite) colonies. We subsequently mapped the B. chinensis invasion as well as co-existing A. rudis and R. flavipes colonies by examining coarse woody material (CWM) for nesting colonies. We tested whether the B. chinensis invasion changed with forest microclimates, covaried with A. rudis and/or R. flavipes occurrence, and whether it was associated with failed dispersal of a dominant understory herb. Our results and observations suggest that B. chinensis shares ecological niche requirements (temperature, moisture and CWM as nesting habitat) with A. rudis, severely diminishing the abundance of this native ant. In supplanting A. rudis, B. chinensis appears to play an equivalent role to A. rudis as a termite predator, but fails as a seed disperser. Essentially, the invader substitutes for the negative but not the positive species interactions, thereby apparently shifting ecological dynamics in the invaded system.

Although rarely considered as a saproxylic insect group, ants are an important, highly abundant insect taxon in dead wood environments worldwide. Ants directly impact the dead wood environment primarily through nesting in standing dead trees, logs, stumps, and coarse and fine woody materials, contributing to the physical breakdown of woody materials. Ants indirectly impact the dead wood environment through predation of a wide variety of arthropods, particularly termites, and by serving as a food source for other animals, particularly birds (woodpeckers) and bears that physically break down dead wood to prey upon ant colonies. The known impacts of ant nesting and predation in dead wood are reviewed with a case study that provides new information on the role of abiotic factors affecting nesting site location in dead wood in the eastern temperate US forests. Results showed horizontal and vertical nest stratification of ant nests that shifted with spatial scale. At broad scales, climate determines disparate ranges among species across a latitudinal gradient. At the scale of a forest floor, however, microsite temperature, moisture, and biotic interactions affect nesting locations in downed logs. Future research aimed at better understanding the interactions between ants and other organisms in dead wood environments is necessary to improve our understanding of the importance of ants in shaping dead wood communities and ecosystem processes like decomposition.

1. Wood decomposition in temperate forests is dominated by termites, fungi, and some species of ants and beetles. Outside of urban areas, temperate termite ecology is largely unknown, particularly when compared to tropical termites and other temperate organisms in the functional guild of wood-decomposing animals. 2. This review combines climate habitat modelling with knowledge of species physiology, behaviour, and community interactions to identify and prioritise future research on temperate termite ecology and biogeography. 3. Using a correlative climate model, the regional distributions of three common temperate forest termite species are shown to correlate with different aspects of climate (e.g. mean versus minimum monthly temperature), but that overall their distributions within temperate systems correlate more strongly with temperature variables than with precipitation variables. 4. Existing data are synthesised to outline how the subterranean, wood-nesting behaviour of most temperate forest termite species links their activity to an additional set of non-climate controls: wood type and tree species, soil depth, fungal activity, ant abundances and phenology, and competitive asymmetries among termite species. 5. Although fine-scale estimates of temperate termite abundances are rare, we provide upper bounds on their ecosystem impacts and illustrate how their regional abundances may influence forest structure and habitat availability for other organisms. 6. This review highlights that rigorous ecological studies in non-urban, intact ecosystems – with a particular focus on community interactions – are critically needed to accurately project future abundances, economic impacts, and ecosystem effects of temperate forest termites.

spatial scale from which they are inferred. We show that the common assumption that climate is a predominant control on decomposition is supported only when local-scale variation is aggregated into mean values. Disaggregated data instead reveal that local-scale factors explain 73% of the variation in wood decomposition, and climate only 28%. Further, the temperature sensitivity of decomposition estimated from local versus mean analyses is 1.3-times greater. Fundamental issues with mean correlations were highlighted decades ago 9,10 , yet mean climate‐decomposition relationships are used to generate simulations that inform management and adaptation under environmental change. Our results suggest that to predict accurately how decomposition will respond to climate change, models must account for local-scale factors that control regional dynamics. Climate is traditionally thought to be the predominant control on decomposition rates at global and regional scales, with biotic factors controlling only local rates 2,4 . Biotic factors are divided into decomposer organisms, such as soil microbes, and the quality (for example, chemical composition) of the plant litter they decompose. Recent work suggests that litter quality may be more important than climate in controlling decomposition rates across biomes worldwide 3,11 , but the influence of decomposer organisms is still assumed limited across broad climate gradients 12 . A core reason for this assumption is that climate is considered a primary control on the activity of decomposers. As such, across climate gradients, mean temperature and moisture availability are assumed to explain much of the variation in the activity of decomposer organisms and hence decomposition rates of organic matter. These climatedecomposition relationships are used to parameterize and evaluate Earth-system models 13 . It is therefore important to test the assumption that climate drives decomposer activities because proper understanding of these activities is needed to inform model projections such as carbon cycleclimate

The language that scientists use to frame biological invasions may reveal inherent bias—including how data are interpreted. A frequent critique of invasion biology is the use of value-laden language that may indicate context bias. Here we use a systematic study of language and interpretation in papers drawn from invasion biology to evaluate whether there is a link between the framing of papers and the interpretation of results. We also examine any trends in context bias in biological invasion research. We examined 651 peer-reviewed invasive species competition studies and implemented a rigorous systematic review to examine bias in the presentation and interpretation of native and invasive competition in invasion biology. We predicted that bias in the presentation of invasive species is increasing, as suggested by several authors, and that bias against invasive species would result in misinterpreting their competitive dominance in correlational observational studies compared to causative experimental studies. We indeed found evidence of bias in the presentation and interpretation of invasive species research; authors often introduced research with invasive species in a negative context and study results were interpreted against invasive species more in correlational studies. However, we also found a distinct decrease in those biases since the mid-2000s. Given that there have been several waves of criticism from scientists both inside and outside invasion biology, our evidence suggests that the subdiscipline has somewhat self-corrected apparent biases.

1. Fire ants naturally invade some undisturbed ecosystems of high conservation value and may negatively impact co-occurring ants. 2. Over 3 years, fire ants were added and removed from a longleaf pine savanna ecosystem that naturally supports a low density of fire ants. Impacts on co-occurring ants were monitored using pitfall traps. 3. Treatments resulted in significant differences in average fire ant abundance across all plots only in the first year of the experiment. Fire ants had little discernible impact. The abundance and species richness of co-occurring ants in removal plots never differed from unmanipulated control plots. The abundance of co-occurring ants was very slightly lower and ant species richness was slightly higher where Solenopsis invicta Buren colonies were added, but neither contrast was significant. 4. The poor conditions in this habitat for many native ants may explain this outcome. More broadly, the impact of fire ants on ant assemblages still appears to be secondary and largely a consequence of human impacts on the environment.

A key shortcoming in our understanding of exotic species' success is that it is not known how post-introduction dispersal contributes to the success of exotic species and the reassembly of invaded communities. Exotic and native species face poorly understood competition-colonization trade-offs in heterogeneous landscapes of natural and anthropogenic habitats. We conducted three experiments that tested how ant queen behavior during dispersal affects community composition. Using experimental plots, we tested whether (1) different types of habitat disturbance and (2) different sizes of habitat disturbance affected the abundance of newly mated queens landing in the plots. The three most abundant species captured were the exotic fire ant Solenopsis invicta, and the native species Brachymyrmex depilis, and S. pergandei, respectively. When queens were considered collectively, more queens landed in plowed, sand-added, and roadside plots than in control or mow plots, in other words, in the more heavily disturbed plots. We also tested (3) the effect of habitat manipulations on the survival of newly mated fire ant queens (Solenopsis invicta). Soil disturbance (tilling), lack of shade, and removal (poisoning) of the ant community resulted in the greatest fire ant colony survivorship. Collectively, experiments revealed that both exotic and native newly mated ant queens select open, human-altered ecosystems for founding new colonies. The selection of such habitats by fire ant queens leads to their successful colony founding and ultimately to their dominance in those habitats. Selection of disturbed habitats is therefore advantageous for exotic species but is an ecological trap for native species because they do not often succeed in founding colonies in these habitats.

Myrmecochory is a facultative, mutualistic interaction in which ants receive a protein-rich food reward (elaiosome) in return for dispersing plant seeds. In North American northeastern hardwood forests, Aphaenogaster ants are the primary genus dispersing myrmecochorous plants. In these forests, myrmecochores occur in plant guilds of understory spring ephemerals or seasonal greens. This mutualism has been demonstrated for Aphaenogaster rudis (Emery) and individual plant species, but it has not been demonstrated for other Aphaenogaster species or guilds of myrmecochores as they naturally occur. Aphaenogaster picea (Wheeler) colonies were fed three treatments over 5 mo: 1) a mixture of only elaiosomes from an entire plant guild, 2) a diet of only insect protein and 3) a combination diet of both elaiosomes and insect protein. This experiment investigated two potential hypotheses through which elaiosomes can benefit ants: 1) elaiosome proteins can substitute for protein nutritional requirements when ants are prey-limited, and 2) elaiosome nutrition can supplement insect protein when prey is ample. First, a mixture of elaiosomes from four myrmecochorous plant species provided to A. picea colonies was sufficient to maintain worker production, larval growth, and fat stores when no other food was available. A. picea colonies consuming elaiosomes as their only protein source could be sustained for a growing season (5 mo). Second, colonies fed both elaiosomes and protein did not yield more productive colonies than a control diet of just insect protein. These results support the hypothesis that myrmecochory is indeed a facultative mutualism in which ants take advantage of the protein content of elaiosomes when it is favorable, but when they are not limited by insect prey they do not gain any additional benefit from elaiosomes.

Biological invasions are often closely associated with human impacts and it is difficult to determine whether either or both are responsible for the negative impacts on native communities. Here, we show that human activity, not biological invasion, is the primary driver of negative effects on native communities and of the process of invasion itself. In a large-scale experiment, we combined additions of the exotic fire ant, Solenopsis invicta , with 2 disturbance treatments, mowing and plowing, in a fully crossed factorial design. Results indicate that plowing, in the absence of fire ants, greatly diminished total native ant abundance and diversity, whereas fire ants, even in the absence of disturbance, diminished some, but not all, native ant abundance and diversity. Transplanted fire ant colonies were favored by disturbance. In the absence of disturbance and on their own, fire ants do not invade the forest habitats of native ants. Our results demonstrate that fire ants are “passengers” rather than “drivers” of ecological change. We propose that fire ants may be representative of other invasive species that would be better described as disturbance specialists. Current pest management and conservation strategies should be reassessed to better account for the central role of human impacts in the process of biological invasion.

Understanding how exotic invasive species are spread is fundamental for ecology and conservation biology. Human transport has become one of the primary modes of dispersal for exotic species. We examined how the multiple queen, or polygyne, social form of the fire ant Solenopsis invicta is spread along roadsides in Tallahassee, Florida, USA. We then determined the likely source of this expanding population, which was a central soil depot. A survey of road maintenance practices in counties of several southeastern states and Texas revealed that the use of a central soil depot is a common practice. Road maintenance therefore may be the primary source for the establishment of new polygyne fire ant populations in this region and elsewhere. Control efforts focused on the soil depots will help to limit further spread of polygyne fire ants and perhaps other invasive organisms, particularly invasive weeds.

The exotic ant, Pheidole obscurithorax Naves, is currently expanding its range and increasing in local density in the southeastern United States. We describe new county records from 5 states and local density increases along roadside transects in the Tallahassee, Florida area. The patchy distribution suggests that this species is being transported to new localities by people. Throughout its introduced range, this species is largely confined to highly disturbed habitats, such as lawns and roadsides and frequently co-occurs with the introduced fire ant, Solenopsis invicta Buren. Locally, although the maximum density of nests per unit area has not changed since 2002, the total area occupied, and the total number of nests of P. obscurithorax is much greater. Beyond these data, little is known of the biology of this species.

Ecological experiments on fire ants cannot, or should not, use poison baits to eliminate the fire ants because such baits are not specific to fire ants, or even to ants. Hot water is an extremely effective and specific killing agent for fire ant colonies, but producing large amounts of hot water in the field, and making the production apparatus mobile have been problematical. The construction and use of a charcoal-fired kiln made from a 55-gal. oil drum lined with a sand-fireclay mixture is described. An automobile heater fan powered from a 12-v battery provided a draft. Dual bilge pumps pumped water from a large tank through a long coil of copper tubing within the kiln to produce 4 to 5 l. of hot water per min. The hot water was collected in 20 l. buckets and poured into fire ant nests previously opened by piercing with a stick. The entire assembly was transported in and operated from the back of a pickup truck. Five experimental plots containing 32 to 38 colonies of the fire ant, Solenopsis invicta, Buren (Hymenoptera: Formicidae), were treated with hot water over a period of two years. All colonies on the treatment plots were treated twice with hot water early in 2004, reducing their numbers to zero. However new colonies were formed, and mature colonies expanded into the plots. A third treatment was made in the spring of 2005, after which fire ant populations were suppressed for over a year. Whereas the 5 control plots contained a total of 166 mostly large colonies, the 5 treatment plots contained no live colonies at all. Averaged over a two-year period, a 70% reduction in total number of colonies was achieved (P < 0.001) on the treatment plots, and a 93% reduction of large, mature colonies. Over this same time span, the number of colonies in control plots remained stable. The reduction in colony numbers on the treatment plots was reflected in the pitfall trap samples that recorded a 60% reduction in fire ants.

Slave making ants of the Polyergus lucidus Mayr (Hymenoptera: Formicidae) complex enslave 3 different Formica species, Formica archboldi, F. dolosa, and F. pallidefalva, in northern Florida. This is the first record of presumed P. lucidus subspecies co-occurring with and enslaving multiple Formica hosts in the southern end of their range. The behavior, colony sizes, body sizes, nest architecture, and other natural history observations of Polyergus colonies and their Formica hosts are reported. The taxonomic and conservation implications of these observations are discussed.

1. The fire ant, Solenopsis invicta, is a globally distributed invasive ant that is largely restricted to disturbed habitats in its introduced range. For more than half a century, biologists have believed its success results from superior competitive abilities relative to native ant species, as well as an escape from their natural enemies. 2. We used large volumes of hot water to kill fire ant colonies, and only fire ant colonies, on experimental plots in pastures, and found that populations and diversity of co-occurring ants did not subsequently increase. 3. These results are contrary to classical predictions and indicate that S. invicta is not a superior competitor that suppresses native ants, and that the low diversity and abundance of native ants in degraded ecosystems does not result from interaction with fire ants. Instead, other factors such as prior disturbance and recruitment limitation may be the primary limiting factors for native species in these habitats.

The growing emphasis on including invertebrates in global biodiversity conservation efforts has prompted an increase in the study of invertebrate assemblages. Invertebrate sampling designs and the bias of individual methods, nevertheless, remain poorly understood for a variety of habitats. We used a structured inventory approach to sampling ants in Þve upland ecosystems in Florida. We evaluated the efÞciency of quantitative and nonquantitative methods for sampling ants. We also evaluated the performance of four species richness estimators. A total of 3,774 species occurrences were distributed among 1,732 samples that contained 94 species from 31 genera. Twenty unique species and 10 duplicate species were collected. Compared with a comprehensive species list for Florida, sampling captured 66% of the regional fauna and 70 Ð90% of species within the ecosystems studied. Combinations of sampling methods were much more effective for assessing species richness. Individual methods were complementary and sampled only part of the entire assemblage. Nonparametric estimators (an incidence-based coverage estimator (ICE) and a jackknife estimator (Jack2)) performed better than lognormal Þtting, and Michaelis-Menten curve extrapola- tion. However, none of the estimators was stable, and their estimates should be viewed with skepticism. The results of this study provide support for the use of the Ants of the Leaf Litter (ALL) protocol for thoroughly sampling ant assemblages in temperate and subtropical ecosystems. Furthermore, our results indicate that even in relatively species-poor (compared with the tropics) temperate and subtropical regions, a large sampling effort that includes multiple sampling methods is the most effective manner of thoroughly sampling an ant assemblage. Therefore, we suggest that structured inventory should be adopted for a wider variety of terrestrial invertebrate studies.

Collectors use a variety of concentrations and types of alcohols to preserve ant specimens. We evaluated existing literature, experimental evidence, and expert myrmecological advice to determine what kind and concentration of alcohol will result in the best preserved specimens for card-point mounting and DNA extraction. For our experimental evaluation, we killed and stored Solenopsis invicta, Camponotus floridanus, and Dorymyrmex bureni workers in isopropanol and ethanol at four concentrations (70, 85, 95, 100%) over three time periods (24 h, 1 month, 6 months). We then compared specimen condition and amenability to manipulation for mounting on card points. Specimens stored in either 95% isopropanol or 95% ethanol for time periods longer than 24 h produced the best specimens for mounting. A literature review revealed that DNA is best preserved in 95–100% ethanol due to the ability of ethanol to more rapidly penetrate cellular membranes and deactivate DNase activity than other primary alcohols. We recommend that general collections of adult ant specimens should be killed and stored in 95% ethanol. Following this recommendation will result in ant specimens that are easier to mount for museum collections and better preserved for molecular studies. A variety of other killing and preservation techniques relevant to the study of ants are also discussed.

Female parasitoids use a hierarchy of cues to locate suitable hosts. We conducted a series of field observations and experiments to examine host location behavior in Pseudacteon tricuspis Borgmeier, a phorid parasitoid of Solenopsis invicta Buren worker ants. The parasitoids were frequently attracted to host workers at disturbed colonies, but were almost never attracted to host workers foraging at baits. When conspecific nonnestmate workers were introduced to baits, resulting in aggressive interactions, parasitoids appeared at the majority of baits. Moreover, larger numbers of parasitoids appeared at baits to which greater numbers of nonnestmate workers had been added. Addition of nonnestmate workers to disturbed colonies resulted in increased numbers of parasitoids attracted. Pseudacteon tricuspis did not display a pattern of uniform distribution at disturbed colonies but often was very abundant at some colony locations while absent or rare at nearby colony locations. Solenopsis invicta workers release alarm pheromones in aggressive interactions with nonnestmates, and this substance is likely an important chemical cue that attracts P. tricuspis flies to host workers from a distance.

A functional group model of ant community composition has been widely used in Australia to analyse biogeographical patterns of ant community structure and the responses of ant communities to disturbance. The model has provided valuable support to the widespread use of ant communities as bioindicators of ecological change. However, the model was developed from studies of arid-zone faunas, and its applicability to the World Heritage rainforests of Queensland's humid tropics has not yet been validated. Here we test predictions based on the functional group model for ant communities in Queensland's humid rainforests, by documenting ant community composition and its responses to disturbance on the Atherton Tablelands. Five sites were studied, comprising two relatively undisturbed reference sites representing contrasting rainforest types, and three previously cleared sites, two of which were undergoing revegetation. A variety of sampling techniques were employed, including pitfall trapping, litter extractions, baiting, and general searching. A total of 50 ant species from 29 genera were collected. Site species richness was highest at the reference sites, and lowest at the unvegetated disturbed site, and overall was negatively related to mean ground temperature. As predicted by the functional group model, behaviorally dominant dolichoderines were uncommon or absent at the reference sites, and the most common ants were Generalized myrmicines and Opportunists. Also as predicted, habitat disturbance favored Opportunists, and, as the disturbance involved canopy clearance, this led to colonization by Iridomyrmex and other Dominant dolichoderines. Opportunists represented about 40% of total ants in traps at the reference sites, compared with 80–95% at the disturbed sites. Except one species, Tropical Climate Specialists and Specialist Predators were absent from disturbed sites. In conclusion, patterns of ant composition in relation to disturbance on the Atherton Tablelands conform to the functional group model that has been widely applied to ant faunas elsewhere in Australia. The model may therefore play an important role in the use of ants as bioindicators of ecological change in the World Heritage rainforests of this region.

Longleaf pine savannas are one of the most threatened ecosystems in the world, yet are understudied. Ants are a functionally important and diverse group of insects in these ecosystems. It is largely unknown how local patterns of species diversity and composition are determined through the interaction of this dominant animal group with abiotic features of longleaf pine ecosystems. Here we describe how an important abiotic variable, depth to water table, relates to ant species distributions at local scales. Pitfall trapping studies across habitat gradients in the Florida coastal plains longleaf pine flatwoods showed that the ant community changed with mild differences in habitat. In this undulating landscape, elevation differences were less than 2 m, and the depth to the water table ranged from < 20 cm to 1.2 m. The plant species composing the ground cover were zoned in response to depth to water, and shading by canopy trees increased over deeper water tables. Of the 27 ant species that were analyzed, depending on the statistical test, seven or eight were significantly more abundant over a deep water table, eight to ten over a shallow one, and nine to eleven were not significantly patterned with respect to depth to water. Ant species preferring sites with shallow groundwater also preferred the shadier parts of the sites, while those preferring sites with deeper groundwater preferred the sunnier parts of the sites. This suggests that one group of species prefers hot-dry conditions, and the other cooler-moist. Factor analysis and abundance-weighted mean site characteristics generally confirmed these results. These results show that ant communities in this region respond to subtle differences in habitat, but whether these differences arise from founding preferences, survival, competition, or some combination of these is not known.

Myrmecochory is a facultative, mutualistic interaction in which ants receive a protein-rich food reward (elaiosome) in return for dispersing plant seeds. In North American northeastern hardwood forests, Aphaenogaster ants are the primary genus dispersing myrmecochorous plants. In these forests, myrmecochores occur in plant guilds of understory spring ephemerals or seasonal greens. This mutualism has been demonstrated for Aphaenogaster rudis (Emery) and individual plant species, but it has not been demonstrated for other Aphaenogaster species or guilds of myrmecochores as they naturally occur. Aphaenogaster picea (Wheeler) colonies were fed three treatments over 5 mo: 1) a mixture of only elaiosomes from an entire plant guild, 2) a diet of only insect protein and 3) a combination diet of both elaiosomes and insect protein. This experiment investigated two potential hypotheses through which elaiosomes can benefit ants: 1) elaiosome proteins can substitute for protein nutritional requirements when ants are prey-limited, and 2) elaiosome nutrition can supplement insect protein when prey is ample. First, a mixture of elaiosomes from four myrmecochorous plant species provided to A. picea colonies was sufficient to maintain worker production, larval growth, and fat stores when no other food was available. A. picea colonies consuming elaiosomes as their only protein source could be sustained for a growing season (5 mo). Second, colonies fed both elaiosomes and protein did not yield more productive colonies than a control diet of just insect protein. These results support the hypothesis that myrmecochory is indeed a facultative mutualism in which ants take advantage of the protein content of elaiosomes when it is favorable, but when they are not limited by insect prey they do not gain any additional benefit from elaiosomes.

Earthworms, termites, and ants are common macroinvertebrates in terrestrial environments, although for most ecosystems data on their abundance and biomass is sparse. Quantifying their areal abundance is a critical first step in understanding their functional importance. We intensively sampled dead wood, litter, and soil in eastern US temperate hardwood forests at four sites, which span much of the latitudinal range of this ecosystem, to estimate the abundance and biomass m(-2) of individuals in macroinvertebrate communities. Macroinvertebrates, other than ants and termites, differed only slightly among sites in total abundance and biomass and they were similar in ordinal composition. Termites and ants were the most abundant macroinvertebrates in dead wood, and ants were the most abundant in litter and soil. Ant abundance and biomass m(-2) in the southernmost site (Florida) were among the highest values recorded for ants in any ecosystem. Ant and termite biomass and abundance varied greatly across the range, from 95% in the southern sites. Our data reveal a pronounced shift to eusocial insect dominance with decreasing latitude in a temperate ecosystem. The extraordinarily high social insect relative abundance outside of the tropics lends support to existing data suggesting that ants, along with termites, are globally the most abundant soil macroinvertebrates, and surpass the majority of other terrestrial animal (vertebrate and invertebrate) groups in biomass m(-2). Our results provide a foundation for improving our understanding of the functional role of social insects in regulating ecosystem processes in temperate forest.

The association of the exotic fire ant, Solenopsis invicta with man-modified habitats has been amply demonstrated, but the fate of such populations if ecological succession proceeds has rarely been investigated. Resurvey of a fire ant population in a longleaf pine plantation after 25 years showed that the recovery of the site from habitat disturbance was associated with a large fire ant population decline. Most of the persisting colonies were associated with the disturbance caused by vehicle tracks. In a second study, mature monogyne fire ant colonies that had been planted in experimental plots in native groundcover of the north Florida longleaf pine forest had mostly vanished six years later. These observations and experiments show that S. invicta colonies rarely persist in the native habitat of these pine forests, probably because they are not replaced when they die. A single site harbored a modest population of polygyne fire ants whose persistence was probably facilitated by reproduction through colony fission.