Litter Ant Communities Research Articles

Six decades of museum collections reveal disruption of native ant assemblages by introduced species

There is a looming environmental crisis characterized by widespread declines in global biodiversity,1,2,3,4,5,6 coupled with the establishment of introduced species at accelerated rates.7,8,9,10,11,12,13,14 We quantified how multi-species invasions affect litter ant communities in natural ecosystems by leveraging museum records and contemporary collections to assemble a large (18,990 occurrences, 6,483 sampled local communities, and 177 species) 54-year (1965-2019) dataset for the entire state of Florida, USA. Nine of ten species that decreased most strongly in relative abundance ("losers") were native, while nine of the top ten "winners" were introduced species. These changes led to shifts in the composition of rare and common species: in 1965, only two of the ten most common ants were introduced, whereas by 2019, six of ten were introduced species. Native losers included seed dispersers and specialist predators, suggesting a potential loss of ecosystem function through time, despite no obvious loss of phylogenetic diversity. We also examined the role of species-level traits as predictors of invasion success. Introduced species were more likely to be polygynous than native species. The tendency to form supercolonies, where workers from separate nests integrate, also differed between native and introduced species and was correlated with the degree to which species increased in their rank abundances over 50 years. In Florida, introduced ants now account for 30% of occurrence records, and up to 70% in southern Florida. If current trends continue, introduced species will account for over half of occurrence records in all Florida's litter ant communities within the next 50 years.

Scale-Dependent Spatial Ecology of Paleotropical Leaf Litter Ants (Hymenoptera: Formicidae)

The grain for which an observer conducts a study is an important determinant of its outcome. Studies of ants have considered spatial grains spanning from single meters to entire forest ecosystems and found patterns related to nutrient availability, leaf litter depth, disturbance, and forest composition. Here, we examine a Bornean leaf litter ant community at small (1–4 m) and large (50–250 m) spatial scales and consider the differences in community structure using structured 1 m2 quadrats sampled via leaf litter sifting and Berlese extraction. We found that small-scale patterns in ant abundance and richness did not spatially autocorrelate within a plot until >1.5 m. Leaf litter characteristics, forest stand characteristics and sampling season were homogenous among our sites, suggesting that macro-scale stand variables are not largely regulating the small spatial scale ant communities: These may be driven by microclimate, competition, niche space, nutrient available, microclimatic conditions, or other localized effects. Further experimental work is needed to elicit causal mechanisms.

Spatiotemporal dynamics of the ant community in a dry forest differ by vertical strata but not by successional stage

AbstractAnts are diverse and ecologically important organisms in tropical forests, where their spatiotemporal distribution can be highly complex. This complexity arises mainly from marked differences in microclimatic conditions and resource availability through space and time that is even more evident in highly seasonal environments, such as tropical dry forests. However, it is unclear how seasonality interacts with other factors that might shape temporal variation of ant composition (β‐diversity), like vertical strata and habitat disturbance. Our goal was to examine the potential influence of vertical stratification and the successional stage on the spatiotemporal variation of a tropical dry forest's ant species composition. We assessed whether species turnover or nestedness was the main component determining the spatiotemporal β‐diversity of ant communities across the canopy and litter strata. We sampled canopy and litter ants in ten plots, half in the early and half on the late stage of secondary succession at four times, twice in wet and twice in dry season. A high species turnover defined the spatiotemporal β‐diversity of canopy and litter ant communities across years and seasons in our focal dry forests. Importantly, the temporal ant species composition was much more stable in the canopy than in the litter. Moreover, we found that the ant community's temporal dynamics was consistently high across successional stages, not differing in the temporal β‐diversity between early and late succession. Our results provide valuable insights into the potential underlying causes of community assembly and spatiotemporal dynamics in seasonal habitats, like the highly threatened and diverse tropical dry forests.Abstract in Portuguese is available with online material.

Environmental determinants of leaf litter ant community composition along an elevational gradient

AbstractAnt communities are extremely diverse and provide a wide variety of ecological functions in tropical forests. Here, we investigated the abiotic factors driving ant composition turnover across an elevational gradient at Mont Itoupé, French Guiana. Mont Itoupé is an isolated mountain whose top is covered by cloud forests, a biogeographical rarity that is likely to be threatened according to climate change scenarios in the region. We examined the influence of six soil, climatic, and LiDAR‐derived vegetation structural variables on leaf litter ant assembly (267 species) across nine 0.12‐ha plots disposed at three elevations (ca. 400, 600, and 800m asl). We tested (a) whether species cooccurring within a same plot or a same elevation were more similar in terms of taxonomic, functional, and phylogenetic composition, than species from different plots/elevations, and (b) which environmental variables significantly explained compositional turnover among plots. We found that the distribution of species and traits of ant communities along the elevational gradient was significantly explained by a turnover of environmental conditions, particularly in soil phosphorus and sand content, canopy height, and mean annual relative humidity of soil. Our results shed light on the role exerted by environmental filtering in shaping ant community assembly in tropical forests. Identifying the environmental determinants of ant species distribution along tropical elevational gradients could help predicting the future impacts of global warming on biodiversity organization in vulnerable environments such as cloud forests.

The ecological implications of rubber‐based agroforestry: Insect conservation and invasion control

AbstractProtected areas are increasingly threatened by biological invasions, especially in tropical Asia where extensive areas of natural habitats have been converted to monoculture plantations. Such disturbance provides a gateway for exotic species invasions, highlighting an urgent need for cross‐boundary solutions to mitigate invasion impacts.Agroforests, with multi‐storied trees and crops resembling the complex structure of natural forest, are known to promote native species compared to monoculture plantations. Yet, our knowledge on their roles in controlling exotic species is limited to plant invaders, with effects on animal invaders still unknown. Given that protected areas are increasingly threatened by invaders from surrounding plantations, with a majority of them represented by insects, it is important to evaluate the effect of agroforestry practice, and mechanisms of associated management to control invasions.By using both taxonomic and functional trait‐based approaches, we studied leaf litter ant communities in 12 rubber monoculture (mono‐rubber), 9 rubber plantation with understory crops (agro‐rubber), 16 secondary and 12 old‐growth secondary forest plots in and around protected areas in Hainan, China. Sampled ants were further classified into groups based on their invasive potential (tramp vs. non‐tramp) to determine the ecological values of agro‐rubber.We found that despite mono‐rubber and agro‐rubber presenting similar species richness, the latter (a) supports species composition and functional diversity more similar to secondary forests and (b) reduces tramp ant species occurrence, a novel management incentive. Nonetheless, agro‐rubber is not comparable to secondary forest in terms of non‐tramp ant species composition.Synthesis and applications.Against the increasing threat of biological invasions, preserving natural forests in human‐dominated landscapes is crucial. Increasing the area of agro‐rubber at the periphery of protected areas as a proactive mitigation can, however, be perceived as an additional measure to reduce invasive species' establishment and spread across the landscape. Plantation‐based agroforestry has emerged as a potential management avenue and incentive for transforming monoculture plantations into a less ‘harmful’ alternative.

Land use impacts poison frog chemical defenses through changes in leaf litter ant communities

ABSTRACT Much of the world’s biodiversity is held within tropical rainforests, which are increasingly fragmented by agricultural practices. In these threatened landscapes, there are many organisms that acquire chemical defenses from their diet and are therefore intimately connected with their local food webs. Poison frogs (Family Dendrobatidae) are one such example, as they acquire alkaloid-based chemical defenses from their diet of leaf litter ants and mites. It is currently unknown how habitat fragmentation impacts chemical defense across trophic levels, from arthropods to frogs. We examined the chemical defenses and diet of the Diablito poison frog (Oophaga sylvatica), and the diversity of their leaf litter ant communities in secondary forest and reclaimed cattle pasture. Notably, this research was performed in collaboration with two high school science classrooms. We found that the leaf litter of forest and pasture frog habitats differed significantly in ant community structure. We also found that forest and pasture frogs differed significantly in diet and alkaloid profiles, where forest frogs contained more of specific alkaloids and ate more ants in both number and volume. Finally, ant species composition of frog diets resembled the surrounding leaf litter, but diets were less variable. This suggests that frogs tend to consume particular ant species within each habitat. To better understand how ants contribute to the alkaloid chemical profiles of frogs, we chemically profiled several ant species and found some alkaloids to be common across many ant species while others are restricted to a few species. At least one alkaloid (223H) found in ants from disturbed sites was also found in skins from pasture frogs. Our experiments are the first to link anthropogenic land use changes to dendrobatid poison frog chemical defenses through variation in leaf litter communities, which has implications for conservation management of these threatened amphibians.

Tropical ant communities are in long-term equilibrium

Communities change with time. Studying long-term change in community structure permits deeper understanding of community dynamics, and allows us to forecast community responses to perturbations at local (e.g. fire, secondary succession) and global (e.g. desertification, global warming) spatial scales. Monitoring efforts exploring the temporal dynamics of indicator taxa are therefore a critical part of conservation agendas. Here, the temporal dynamics of the Otongachi leaf litter ant community, occurring in a cloud forest in coastal Ecuador, were explored. By sampling this community six times over eleven years, I assessed how the ant fauna caught by Winkler traps (more diverse and cryptic fauna) and caught by pitfall traps (larger, more mobile fauna) changed over time. The Otongachi leaf litter ant community was dynamic. Although species richness in the community remained constant, temporal turnover of species was high: on average, 51% of the ant species in Winkler traps, and 56% of those in pitfall traps, were replaced with other ant species from one year to the other. Shifts in the rank abundance of species in the community were also large across the eleven years and, on average, shifts in the rank abundance of species collected by Winkler traps doubled those occurring in pitfall traps from one census to the other. In spite of these trends, the Otongachi ant fauna showed no (Winkler) or weak (pitfall) evidence of directional change (towards a new community). Thus, this tropical ant community can be divided in two community compartments. The Winkler compartment composed by a more diverse and cryptic ant fauna appears to be resilient and stable in time. The pitfall compartment composed by larger and more mobile ants may be prone to respond to disturbance. This study suggests that 1) species appearing/disappearing from a site may be rather the rule, difficult to separate from responses to ecological stress. 2) Conclusions made in short-term studies, or studies comparing two (e.g. before and after) snapshots of a community, should thus be revisited. Finally, 3) the ant fauna caught by pitfall traps (a rather simple and cheap survey method) is the most likely community compartment to indicate ecological perturbation. This study adds to the growing evidence that using ants as ecological indicators should incorporate long-term temporal dynamics.

Riparian reserves within oil palm plantations conserve logged forest leaf litter ant communities and maintain associated scavenging rates.

Summary The expansion of oil palm plantations at the expense of tropical forests is causing declines in many species and altering ecosystem functions. Maintaining forest‐dependent species and processes in these landscapes may therefore limit the negative impacts of this economically important industry. Protecting riparian vegetation may be one such opportunity; forest buffer strips are commonly protected for hydrological reasons, but can also conserve functionally important taxa and the processes they support.We surveyed leaf litter ant communities within oil palm‐dominated landscapes in Sabah, Malaysia, using protein baits. As the scavenging activity of ants influences important ecological characteristics such as nutrient cycling and soil structure, we quantified species‐specific rates of bait removal to examine how this process may change across land uses and establish which changes in community structure underlie observed shifts in activity.Riparian reserves had similar ant species richness, community composition and scavenging rates to nearby continuous logged forest. Reserve width and vegetation structure did not affect ant species richness significantly. However, the number of foraging individuals decreased with increasing reserve width, and scavenging rate increased with vegetation complexity.Oil palm ant communities were characterized by significantly lower species richness than logged forest and riparian reserves and also by altered community composition and reduced scavenging rates.Reduced scavenging activity in oil palm was not explained by a reduction in ant species richness, nor by replacement of forest ant species by those with lower per species scavenging rates. There was also no significant effect of land use on the scavenging activity of the forest species that persisted in oil palm. Rather, changes in scavenging activity were best explained by a reduction in the mean rate of bait removal per individual ant across all species in the community. Synthesis and applications. Our results suggest that riparian reserves are comparable to areas of logged forest in terms of ant community composition and ant‐mediated scavenging. Hence, in addition to protecting large continuous areas of primary and logged forest, maintaining riparian reserves is a successful strategy for conserving leaf litter ants and their scavenging activities in tropical agricultural landscapes.

Ecosystem-Wide Morphological Structure of Leaf-Litter Ant Communities along a Tropical Latitudinal Gradient

General principles that shape community structure can be described based on a functional trait approach grounded on predictive models; increased attention has been paid to factors accounting for the functional diversity of species assemblages and its association with species richness along environmental gradients. We analyze here the interaction between leaf-litter ant species richness, the local communities' morphological structure and fundamental niche within the context of a northeast-southeast latitudinal gradient in one of the world's most species-rich ecosystems, the Atlantic Forest, representing 2,700 km of tropical rainforest along almost 20o of latitude in eastern Brazil. Our results are consistent with an ecosystem-wide pattern in communities' structure, with relatively high species turnover but functionally analogous leaf-litter ant communities' organization. Our results suggest directional shifts in the morphological space along the environmental gradient from overdispersed to aggregated (from North to South), suggesting that primary productivity and environmental heterogeneity (altitude, temperature and precipitation in the case) determine the distribution of traits and regulate the assembly rules, shaping local leaf-litter ant communities. Contrary to the expected and most common pattern along latitudinal gradients, the Atlantic Forest leaf litter ant communities show an inverse pattern in richness, that is, richer communities in higher than in lower latitudes. The morphological specialization of communities showed more morphologically distinct communities at low latitudes and species redundancy at high latitudes. We claim that an inverse latitudinal gradient in primary productivity and environmental heterogeneity across the Atlantic forest may affect morphological diversity and species richness, enhancing species coexistence mechanisms, and producing thus the observed patterns. We suggest that a functional framework based on flexible enough traits should be pursued to allow comparisons at local, regional and global levels.

Assembly mechanisms shaping tropical litter ant communities

Community ecology seeks to unravel the mechanisms that allow species to coexist in space. Some of the contending mechanisms may generate tractable signatures in the amount of trait and phylogenetic dispersion among co‐existing species. When a community presents a pattern with reduced trait or phylogenetic dispersion, mechanisms based on ecological filters are brought into consideration. On the other hand, limiting similarity mechanisms such as competitive exclusion are proposed when communities present patterns of trait or phylogenetic even‐dispersion. The strength of these mechanisms likely varies with the spatial scale of an observed sample. I surveyed species‐rich tropical litter ant communities in a spatially nested design that allowed me to explore the spatial scales, fine (0.25 m2), intermediate (9 m2), and broad (361 m2) at which these mechanisms act. I then assessed the relationship between observed ant communities and potential species pools ranging in size, from plot, site, and island‐wide areas. Patterns of phylogenetic dispersion within ant communities suggested that ant communities were composed of species that were more closely related than expected by a random sampling of phylogenetic pools. The magnitude of phylogenetic ‘clustering’ increased with the size of the species pool but was similar among communities assembled from different spatial scales. Patterns of dispersion of one ecological trait (i.e. body size) within ant communities also showed clustering of body sizes, and most communities were composed of ant species that were smaller than expected by a random sampling of trait pools. Trait clustering increased with the size of the species pool but decreased at broad spatial scales. Together, these results suggest that ecological filters, not interspecific interactions, are structuring tropical ant communities, favoring clades with small worker sizes. The larger dependency on the size of regional pools than on the spatial scale suggests that environmental heterogeneity is greater among than within the study sites.

Short-Term Effects of Prescribed Burning on Ant (Hymenoptera: Formicidae) Assemblages in Ozark Forests

Abstract Prescribed fire is a valuable and effective tool in forest management, and understanding the effects of fire on animal communities is increasingly important for monitoring and conservation. We quantified the short-term responses of leaf litter ants to fire in Ozark oak-dominated forests of Arkansas. We repeatedly surveyed litter ants in replicate burned and unburned sites via Berlese extraction, baiting, and hand collecting 30–170 d postfire. We collected 6,301 ants representing 59 species. Cumulative ant species richness was lower in burned forests than in unburned forests. However, differences in average richness and abundance between treatments were inconsistent overtime; lower ant abundance and species richness in burned sites occurred only during the first few months postburn. Ant species composition was very similar between treatments, although some species typically associated within mesic and lowland habitats were found only in unburned forests. We conclude that litter ant communities in Ozark forests, as in other regions, are relatively resilient to the effects of prescribed burning.

The responses of leaf litter ant communities to wildfires in the Brazilian Amazon: a multi-region assessment

Fire is frequently used as tool for land management in the Amazon, but often escapes into surrounding forests, with potentially severe impacts for forest biodiversity. We investigated the effects of single wildfires on ant communities in four geographically distinct regions of the Brazilian Amazon (Roraima, Para, Acre and Mato Grosso) where forests had burned between 8 months and 10 years before our sampling. We established 7–12 transects, 500 m each, in burned and unburned forests in each region to investigate the effects of fire on forest structure and leaf litter ant communities, which were sampled using Winkler sacks. Fire effects on forest structure were more drastic in the most recently burned forests in Acre and Mato Grosso, while the impacts of older burns in Roraima and Para were more subtle. Ant species richness was not different between burnt and unburned areas, but community composition differed between burned and control forests in all regions except Mato Grosso. At the species level, indicator species analysis showed that a limited number of species were significant indicators of unburned control forests in all regions, except Acre. Forests structure variables and leaf litter volume were all important in shaping ant communities, but their relative importance varied between regions. Our results indicate that burned forest have different ant species communities from unburned forests, and those differences are still apparent 10 years after the disturbance, highlighting the importance of effective policies for fire management in Amazon.

Using nutritional ecology to predict community structure: a field test in Neotropical ants

Nutritional ecology predicts consumer behavior based on the biochemistry of species and biogeochemistry of the environment. It is thus well suited as a tool for predicting the effects of specific nutrients on consumer activity, abundance, and diversity across the landscape. We tested hypotheses from nutritional ecology in a Neotropical litter ant community by supplementing forest plots with carbohydrates (CHOs) and protein in a blocked factorial design. We tested the Compensation Hypothesis, which posits that consumers accumulate in patches of the rarest food type relative to demand, and the Economics Hypothesis, which assumes that species differ in nutrient based‐functional traits, and that changes in nutrient availability will generate changes in species composition and community behavior. We found that CHO and protein had distinct effects on ant density, community composition, and per‐worker activity. Ant density increased by 35% on +CHO plots but not +Protein plots, a result supporting the Compensation Hypothesis because CHO‐rich plant exudates are uncommon and CHO‐demanding microbial productivity is high in this brown food web. Consistent with the Economics Hypothesis, we found that +CHO plots had higher per‐capita ant activity (the Metabolic Fuel Hypothesis) and attracted ants averaging 10% lower δ15N values. Species composition changed as well, with Wasmannia auropunctata, an invasive outside its native range, elsewhere, increasing five‐fold on +CHO plots. Nutritional ecology can thus account for some of the patchiness and behavior of consumers in diverse communities.

Biodiversity Assessment in Incomplete Inventories: Leaf Litter Ant Communities in Several Types of Bornean Rain Forest

Biodiversity assessment of tropical taxa is hampered by their tremendous richness, which leads to large numbers of singletons and incomplete inventories in survey studies. Species estimators can be used for assessment of alpha diversity, but calculation of beta diversity is hampered by pseudo-turnover of species in undersampled plots. To assess the impact of unseen species, we investigated different methods, including an unbiased estimator of Shannon beta diversity that was compared to biased calculations. We studied alpha and beta diversity of a diverse ground ant assemblage from the Southeast Asian island of Borneo in different types of tropical forest: diperocarp forest, alluvial forest, limestone forest and heath forests. Forests varied in plant composition, geology, flooding regimes and other environmental parameters. We tested whether forest types differed in species composition and if species turnover was a function of the distance between plots at different spatial scales. As pseudo-turnover may bias beta diversity we hypothesized a large effect of unseen species reducing beta diversity. We sampled 206 ant species (25% singletons) from ten subfamilies and 55 genera. Diversity partitioning among the four forest types revealed that whereas alpha species richness and alpha Shannon diversity were significantly smaller than expected, beta-diversity for both measurements was significantly higher than expected by chance. This result was confirmed when we used the unbiased estimation of Shannon diversity: while alpha diversity was much higher, beta diversity differed only slightly from biased calculations. Beta diversity as measured with the Chao-Sørensen or Morisita-Horn Index correlated with distance between transects and between sample points, indicating a distance decay of similarity between communities. We conclude that habitat heterogeneity has a high influence on ant diversity and species turnover in tropical sites and that unseen species may have only little impact on calculation of Shannon beta diversity when sampling effort has been high.

The influence of nest availability on the abundance and diversity of twig-dwelling ants in a Papua New Guinea forest

Tropical ant communities are frequently diverse, but highly patchy in nature. The availability of suitable nest sites may be a regulating force in structuring litter ant communities. Our aim was to examine ant resource utilization in naturally occurring twigs, and to modify the availability of these resources in order to quantify the influence of nest availability on ant communities in a Papua New Guinean forest. First, we compared ant communities that assemble in artificial twigs (drilled, wooden dowels), naturally occurring twigs, and the leaf litter. A total of 55 ant species were captured: 33 from the leaf litter, 29 from naturally occurring twigs, and only 12 from artificial nests. Significantly different communities formed in each of the three nest types. Second, we examined how the density of natural or artificial nest material influenced the ant abundance and species richness. Plots had between 5 and 96 potential nest sites. An average of only 11.2% of these twigs was colonized. Both species richness and the total abundance of adult ants were significantly positively correlated with increasing naturally occurring twig density. Conversely, increasing the availability of artificial nests from 5 to 20 per plot had no significant effect on the proportion of artificial nests colonized, species richness, or the colony size. We observed that ant species richness and abundance increased with natural twig density, at least for naturally occurring communities. But why so many twigs remain vacant and available for ant colonization remains unknown. Other biotic and abiotic factors likely influence the use of nesting habitat in these ant communities.

More food, less habitat: how necromass and leaf litter decomposition combine to regulate a litter ant community

1. In brown food webs of the forest floor, necromass (e.g. insect carcasses and frass) falling from the canopy feeds both microbes and ants, with the former decomposing the homes of the latter. In a tropical litter ant community, we added necromass to 1 m2 plots, testing if it added as a net food (increasing ant colony growth and recruitment) or destroyer of habitat (by decomposing leaf litter).2. Maximum, but not mean, colony growth rates were higher on +food plots. However, neither average colony size, nor density was higher on +food plots. In contrast, +food plots saw diminished availability of leaf litter and higher microbial decomposition of cellulose, a main component of the organic substrate that comprises litter habitat.3. Furthermore, necromass acted as a limiting resource to the ant community only when nest sites were supplemented on +food plots in a second experiment. Many of these +food +nest plots were colonised by the weedy species Wasmannia auropunctata.4. Combined, these results support the more food–less habitat hypothesis and highlight the importance of embedding studies of litter ant ecology within broader decomposer food web dynamics.

Morphological patterns and community organization in leaf‐litter ant assemblages

We present a new approach to determine the number and composition of guilds, using the hyperdiverse leaf‐litter ant fauna as a model, based on appropriate morphological variables and species co‐occurrence null models to describe the complex assemblages of interacting species community structure at the 1‐m2scale. We obtained 18 linear morphometric measures from 949 workers of 171 leaf‐litter ant species (18 762 measurements) surveyed in four Atlantic Forest localities to test whether the assemblages are morphologically structured; the morphological characters were selected to indicate diet and foraging habits. Principal components analysis was used to characterize the morphospace and to describe the guild structure (number of species and composition). The guild proportionality assembly rule (significant tendency toward constant proportion of species in guilds) was assessed at the 1‐m2scale. Our analysis indicates that the division of leaf‐litter ants into guilds is based mainly on microhabitat distribution in the leaf‐litter, body size and shape, eye size, and phylogeny. The same guild scheme applied to four more sites shows that different Atlantic Forest areas have the same leaf‐litter ant guilds. The guild proportionality assembly rule was confirmed for most guilds, suggesting that there are guild‐specific limitations on species coexistence within assemblages; on the other hand, in a few cases the variance in guild proportion was greater than expected under the null assumptions. Other studies on ant functional group classification are partially supported by our quantitative morphological analysis. Our results, however, imply that there are more compartments than indicated in previous models, particularly among cryptic species (confined to soil and litter) and tropical climate specialists. We argue that a general null model for the analysis of species association based on morphology can reveal objectively defined groups and may thus contribute to a robust theory to explain community structure in general and have important consequences on studies of litter ant community ecology in particular.

Composition of a high diversity leaf litter ant community (Hymenoptera: Formicidae) from an Ecuadorian pre-montane rainforest

The pre-montane forest of the northern Andes is considered one of the most biodiverse regions in the world. Tools for rapidly assessing biodiversity inventories are currently being developed and may aid conservation efforts. Here, we focus on the use of the Ants of the Leaf Litter (ALL) protocol as such a tool and describe the composition of an Ecuadorian pre-montane leaf litter ant community. Two 200-m transects (i.e. two complete replications of the protocol) with a total of 40 winkler sacs and 39 pitfall traps were analyzed. In total, we collected 4 875 specimens from 103 species, 37 genera and 9 subfamilies. The abundance-based coverage estimator (ACE), an asymptotic estimator of species richness, predicted a total of 109 ant species for the forest fl oor, making this ant community one of the most diverse recorded in tropical mid-altitude forests. Subsets of the community sampled by winkler sacs and pitfall traps differed signifi cantly. Winkler sacs were more effi cient than pitfall traps at capturing individual ants (226% more) and species (129% more). Relative to pitfall traps, an analysis of morphology suggested that winkler sacs collected a subset of the ant community that was smaller, less mobile and with smaller eyes (e.g. more subterranean). Finally, we present the fi rst published records of the ant species Acanthognathus teledectus Brown & Kempf 1969, Hypoponera distinguenda (Emery 1890), Prionopelta amabilis Borgmeier 1949, Pachycondyla chyzeri (Forel 1907) and Procryptocerus mayri Forel 1899 for Ecuador.

Community structure and functional group classification of litter ants in the montane evergreen and deciduous forests of Wayanad region of Western Ghats, Southern India

Community structure of litter ants based on feeding guilds and the more recent functional group classification, and also the role of abiotic factors in determining the community structure have been analyzed following ‘Ants of Leaf Litter’ protocol in a montane evergreen (shola) and deciduous forests in the Wayanad region of Western Ghats, southern India. Distinct variations in the guild structure of litter ant communities in shola and deciduous forests have been recorded. Predators dominated deciduous and omnivores in the shola forests. Cryptic species was the dominant functional guild in both litter stands, although hot-climate specialists have not been recorded from the shola forests. Rank-abundance plots attributed the difference in diversity between the forests to the dominance of Tapinoma sp. and Myrmicaria brunnea in deciduous forest. Physical characteristics of the habitat critically influenced ant abundance in both forest types. Functional group model classification was found to be a better model for the classification of litter ants than the conventional feeding-guild categorization as it enabled a meaningful comparison in relation to physical factors.

Leaf litter ant diversity in Guyana

Leaf litter ants are an important group of organisms for informing conservation planning. This study presents the beginning of a leaf litter ant dataset for Guyana. Following the ants of the leaf litter protocol, ants were extracted from sifted leaf litter sampled along eight transects from across Guyana. A total of 230 species were collected from 44 genera. Of those 230 species, 122 species (ca. 53%) were found at only one site. Out of the 122 species found at only one site, 43 species (ca. 19%) were singletons, being known from only one specimen. Using a cluster analysis, faunistic composition was compared among sites. While the lowland sites accounted for the highest species richness, Mt. Ayanganna possessed an especially distinctive ant fauna and may represent a center of endemism. Three leaf litter ant communities were identified: lowland and two Mt. Ayanganna communities, mid-elevation and upper elevation. Recent mining operations on Mt. Ayanganna threaten its pristine nature and this study confirms the need for further biological study of the area. With upwards of 70% of its area still forested Guyana has the opportunity to preserve its biological heritage before widespread deforestation occurs. If expanded, this leaf litter ant dataset will be increasingly useful for country-wide conservation planning.