Fire and ant interactions mediated by honeydew and extrafloral nectar in an australian tropical savanna.

Fire is a major disturbance affecting ecosystems globally, but its impact on mutualisms has received minimal attention. Here, we use a long-term field experiment to investigate the impact of different fire regimes on globally important ant-honeydew and ant-extrafloral nectar (EFN) mutualistic interactions in an Australian tropical savanna. These interactions provide ants with a key energy source, while their plant and hemipteran hosts receive protection services. We examined ant interactions on species of Eucalyptus (lacking EFNs) and Acacia (with EFNs) in three replicate plots each of burning every 2 and 3 years early in the dry season, burning late in the dry season every 2 years, and unburnt for > 25 years. The proportions of plants with ant-honeydew interactions in Acacia (44.6%) and Eucalyptus (36.3%) were double those of Acacia plants with ant-EFN interactions (18.9%). The most common ants, representing 85% of all interactions, were behaviourally dominant species of Oecophylla, Iridomyrmex and Papyrius. Fire promoted the incidence of ant interactions, especially those involving EFNs on Acacia, which occurred on only 3% of plants in unburnt plots compared with 24% in frequently burnt plots. Fire also promoted the relative incidence of behaviourally dominant ants, which are considered the highest quality mutualists. Contrary to expectations, frequent fire did not result in a switching of behaviourally dominant ant partners from forest-adapted Oecophylla to arid-adapted Iridomyrmex. Our findings that frequent fire increases ant interactions mediated by honeydew and extrafloral nectar, and promotes the quality of ant mutualists, have important implications for protective services provided by ants in highly fire-prone ecosystems.

Critical thermal maxima in neotropical ants at colony, population, and community levels.

Global warming is exposing many organisms to severe thermal conditions and is having impacts at multiple levels of biological organisation, from individuals to species and beyond. Biotic and abiotic factors can influence organismal thermal tolerance, shaping responses to climate change. In eusocial ants, thermal tolerance can be measured at the colony level (among workers within colonies), the population level (among colonies within species), and the community level (among species). We analysed critical thermal maxima (CTmax) across these three levels for ants in a semiarid region of northeastern Brazil. We examined the individual and combined effects of phylogeny, body size (BS), and nesting microhabitat on community-level CTmax and the individual effects of BS on population- and colony-level CTmax. We sampled 1864 workers from 99 ant colonies across 47 species, for which we characterised CTmax, nesting microhabitat, BS, and phylogenetic history. Among species, CTmax ranged from 39.3 to 49.7°C, and community-level differences were best explained by phylogeny and BS. For more than half of the species, CTmax differed significantly among colonies in a way that was not explained by BS. Notably, there was almost as much variability in CTmax within colonies as within the entire community. Monomorphic and polymorphic species exhibited similar levels of CTmax variability within colonies, a pattern not always explained by BS. This vital intra- and inter-colony variability in thermal tolerance is likely allows tropical ant species to better cope with climate change. Our results underscore why ecological research must examine multiple levels of biological organisation.

Long-term strict ant-plant mutualism identity characterises growth rate and leaf shearing resistance of an Amazonian myrmecophyte.

Over 125 million years of ant-plant interactions have culminated in one of the most intriguing evolutionary outcomes in life history. The myrmecophyte Duroia hirsuta (Rubiaceae) is known for its mutualistic association with the ant Myrmelachista schumanni and several other species, mainly Azteca, in the north-western Amazon. While both ants provide indirect defences to plants, only M. schumanni nests in plant domatia and has the unique behaviour of clearing the surroundings of its host tree from heterospecific plants, potentially increasing resource availability to its host. Using a 12-year survey, we asked how the continuous presence of either only M. schumanni or only Azteca spp. benefits the growth and defence traits of host trees. We found that the continuous presence of M. schumanni improved relative growth rates and leaf shearing resistance of Duroia better than trees with Azteca. However, leaf herbivory, dry matter content, trichome density, and secondary metabolite production were the same in all trees. Survival depended directly on ant association (> 94% of trees died when ants were absent). This study extends our understanding of the long-term effects of strict ant-plant mutualism on host plant traits in the field and reinforces the use of D. hirsuta-M. schumanni as a model system suitable for eco-co-evolutionary research on plant-animal interactions.

Evolutionary déjà vu? A case of convergent evolution in an ant-plant association.

Obligatory ant-plant symbioses often appear to be single evolutionary shifts within particular ant lineages; however, convergence can be revealed once natural history observations are complemented with molecular phylogenetics. Here, we describe a remarkable example of convergent evolution in an ant-plant symbiotic system. Exclusively arboreal, Myrmelachista species can be generalized opportunists nesting in several plant species or obligately symbiotic, live-stem nesters of a narrow set of plant species. Instances of specialization within Myrmelachista are known from northern South America and throughout Middle America. In Middle America, a diverse radiation of specialists occupies understory treelets of lowland rainforests. The morphological and behavioural uniformity of specialists suggests that they form a monophyletic assemblage, diversifying after a single origin of specialization. Using ultraconserved element phylogenomics and ancestral state reconstructions, we show that shifts from opportunistic to obligately symbiotic evolved independently in South and Middle America. Furthermore, our analyses support a remarkable case of convergence within the Middle American radiation, with two independently evolved specialist clades, arising nearly simultaneously from putative opportunistic ancestors during the late Pliocene. This repeated evolution of a complex phenotype suggests similar mechanisms behind trait shifts from opportunists to specialists, generating further questions about the selective forces driving specialization.

Taxon-dependent diversity response along a temperate elevation gradient covered by grassland.

Elevational gradients constitute excellent systems for understanding the mechanisms that generate and maintain global biodiversity patterns. Climatic gradients associated with elevation show strong influence on species distribution in mountains. The study of mountains covered by the same habitat type is an ideal scenario to compare alternatives to the energy hypotheses. Our aim was to investigate how changes in climatic conditions along the elevational gradient drive α- and ß-diversity of four taxa in a mountain system located within a grassland biome. We sampled ants, spiders, birds and plants, and measured climatic variables at six elevational bands (with 10 sampling sites each) established between 470 and 1,000 masl on a mountain from the Ventania Mountain System, Argentina. Species richness per site and ß-diversity (turnover and nestedness) between the lowest band and upper sites were estimated. For most taxa, species richness declined at high elevations and energy, through temperature, was the major driver of species richness for ants, plants and birds, prevailing over productivity and water availability. The major ß-diversity component was turnover for plants, spiders and birds, and nestedness for ants. The unique environmental conditions of the upper bands could favour the occurrence of specialist and endemic species.

With the dead under the mat: the zombie ant extended phenotype under a new perspective.

Some parasitic fungi can increase fitness by modifying the behavior of their hosts. These behaviors are known as extended phenotypes because they favor parasitic gene propagation. Here, we studied three lineages of Ophiocordyceps, a fungus that infects ants, altering their conduct before death. According to fungal strategy, ants may die in leaf litter, with entwined legs in branches, under the moss mat, or biting plant tissue. It is critical for parasites that the corpses stay at these places because Ophiocordyceps exhibit iteroparity, possibly releasing spores in multiple life cycles. Thus, we assumed substrate cadaver permanence as a fungi reproductive proxy and corpse height as a proxy of cadaver removal. We hypothesize that biting vegetation and dying in higher places may increase the permanence of ant corpses while avoiding possible corpse predation on the forest floor. We monitored over a year more than 4000 zombie ants in approximately 15 km2 of undisturbed tropical forest in central Amazonia. Our results show a longer permanence of corpses with increasing ground height, suggesting that the parasites may have better chances of releasing spores and infecting new hosts at these places. We found that the zombie ants that last longer on the substrate die under the moss mat in tree trunks, not necessarily biting vegetation. The biting behavior appears to be the most derived and complex mechanism among Ophiocordyceps syndromes. Our results put these findings under a new perspective, proposing that seemingly less complex behavioral changes are ecologically equivalent and adaptative for other parasite lineages.

Scavenging in two mountain ecosystems: Distinctive contribution of ants in grassland and non-ant invertebrates in forest.

Scavenging is a key process for the cycling of nutrients in ecosystems, yet it is still neglected in the ecological literature. Apart from the importance of specific groups of animals in scavenging, there have been few ecological studies that compare them. Furthermore, the ecological studies on scavenging have mainly focused on vertebrates despite the crucial importance of invertebrates in this process. Here, we performed a large-scale ant suppression and vertebrate exclusion experiment to quantify the relative contribution of ants, non-ant invertebrates and vertebrates in scavenging nitrogen-rich (insect carcasses) and carbon-rich (seeds) baits in two contrasting mountainous habitats in Brazil (grasslands and forests). Overall, bait removal was 23.2% higher in forests than in grasslands. Ants were the primary scavengers in grasslands, responsible for more than 57% of dead insect larvae and seed removal, while, in forests, non-ant invertebrates dominated, removing nearly 65% of all baits. Vertebrates had a minor role in scavenging dead insect larvae and seeds in both habitats, with <4% of removals. Furthermore, our results show that animal-based baits were more consumed in forests than seeds, and both resources were equally consumed in grasslands. Therefore, we demonstrate the superiority of invertebrates in this process, with a particular emphasis on the irreplaceable role of ants, especially in this grassland ecosystem. As such, we further advance our knowledge of a key ecosystem process, showing the relative importance of three major groups in scavenging and the differences in ecosystems functioning between two contrasting tropical habitats.

Considering climate change impact on the global potential geographical distribution of the invasive Argentine ant and little fire ant.

The Argentine ant (Linepithema humile) and the little fire ant (Wasmannia auropunctata) are among the top 100 invasive alien species globally, causing significant ecological and economic harm. Therefore, it is crucial to study their potential geographic distribution worldwide. This study aimed to predict their global distribution under current and future climate conditions. We used distribution data from various sources, including CABI, GBIF, and PIAKey, and key climate variables selected from 19 environmental factors to model their potential geographic distribution using MaxEnt. The AUC values were 0.925 and 0.937 for L. humile and W. auropunctata, respectively, indicating good predictive performance. Suitable areas for L. humile were mainly in southern North America, northern South America, Europe, central Asia, southern Oceania, and parts of Africa, while W. auropunctata suitable areas were mostly in southern North America, most of South America, a small part of Europe, southern Asia, central Africa, and some parts of Oceania. Under climate change scenario, suitable areas for L. humile increased, while highly suitable areas for W. auropunctata decreased. The top four countries with the largest areas of overlapping suitable habitat under current climate were Brazil, China, Australia, and Argentina, while under future SSP585 climate scenario, the top four countries were Brazil, China, Indonesia, and Argentina. Some countries, such as Estonia and Finland, will see an overlapping adaptation area under climate change. In conclusion, this study provides insight into controlling the spread and harm of L. humile and W. auropunctata.

Low Intraspecific Aggression Level, Cuticular Hydrocarbons, and Polydomy in the Bullet Ant.

Ants use chemical cues known as cuticular hydrocarbons (CHCs) for both intraspecific and interspecific recognition. These compounds serve ants in distinguishing between nestmates and non-nestmates, enabling them to coexist in polydomous colonies characterized by socially connected yet spatially separated nests. Hence, the aim of this study was to investigate the intraspecific aggression level between nestmates and non-nestmates of the bullet ant Paraponera clavata (Fabricius, 1775), analyze and compare their CHCs, and evaluate the occurrence of polydomy in this species. We conducted aggression tests between foragers, both in laboratory and field settings. To identify the chemical profiles, we utilized gas chromatography coupled with mass spectrometry (GC-MS). We marked the foragers found at nest entrances and subsequently recaptured these marked ants to validate workers exchange among nests. Across all nests, a low intraspecific aggression level was observed within the same area. However, a significant difference in aggression correlated to distance between nests. Analysis of the cuticular chemical profile of P. clavata unveiled colony-specific CHCs, both qualitatively and quantitatively. Notably, we observed instances of ants from certain nests entering or exiting different nests. This behavior, in conjunction with the observed low intraspecific aggression despite differences in CHCs suggests polydomy for this species. Polydomy can offer several benefits, including risk spreading, efficient exploitation of resources, potential for colony size increasing and reduced costs associated with foraging and competition.

Leafcutter ants enhance microbial drought resilience in tropical forest soil.

We conducted a research campaign in a neotropical rainforest in Costa Rica throughout the drought phase of an El-Nino Southern Oscillation event to determine microbial community dynamics and soil C fluxes. Our study included nests of the leafcutter ant Atta cephalotes, as soil disturbances made by these ecosystem engineers may influence microbial drought response. Drought decreased the diversity of microbes and the abundance of core microbiome taxa, including Verrucomicrobial bacteria and Sordariomycete fungi. Despite initial responses of decreasing diversity and altered composition, 6 months post-drought the microbiomes were similar to pre-drought conditions, demonstrating the resilience of soil microbial communities to drought events. A. cephalotes nests altered fungal composition in the surrounding soil, and reduced both fungal mortality and growth of Acidobacteria post-drought. Drought increased CH4 consumption in soils due to lower soil moisture, and A. cephalotes nests decrease the variability of CH4 emissions in some soil types. CH4 emissions were tracked by the abundance of methanotrophic bacteria and fungal composition. These results characterize the microbiome of tropical soils across both time and space during drought and provide evidence for the importance of leafcutter ant nests in shaping soil microbiomes and enhancing microbial resilience during climatic perturbations.

Influence of Host Plants and Tending Ants on the Cuticular Hydrocarbon Profile of a Generalist Myrmecophilous Caterpillar.

In myrmecophilous organisms, which live in symbiosis with ants, cuticular hydrocarbons (CHCs) play a pivotal role in interspecific communication and defense against chemical-oriented predators. Although these interactions form complex information webs, little is known about the influence of biotic environmental factors on the CHC profiles of myrmecophiles. Here, we analyzed the effect of different host plants and tending ants on the larval CHC profile of Synargis calyce (Lepidoptera: Riodinidae), a polyphagous species with facultative myrmecophily. Groups of caterpillars were fed individually with three host plant species (without tending ants), and with two tending ant species. Through gas chromatography analysis, we compared the cuticular profiles of treatments and found a high similarity between plants and caterpillars (65-82%), but a low similarity between caterpillars and their tending ants (30 - 25%). Cluster analysis showed that caterpillars, ants, and plants form distinct groups, indicating that S. calyce caterpillars have their own chemical profile. These results are similar to those observed for Lycaenidae caterpillars indicating that there is functional convergence in the chemical strategies used by myrmecophilous caterpillar species with similar ecology. Also, the results suggest that the cuticular compounds of S. calyce are primarily influenced by their host plants rather than their tending ants. Thus, we propose that these caterpillars present a trade-off between camouflage and directly informing their presence to ants, maintaining their unique chemical profile, though slightly affected by biotic environmental factors.

Interspecific insect relationships on Terminalia argentea (Myrtales: Combretaceae) trees in the Cerrado biome.

Terminalia argentea Mart. (Combretaceae), native to Brazil, is used in habitat restoration programs. Arthropods are bioindicators because their populations reflect changes in the environment. We evaluated the recovery of a degraded area by using ecological indices and analyzing arthropod interactions on T. argentea plants. The richness and diversity of sap-sucking Hemiptera and the abundance of tending ants and Sternorrhyncha predators increased with the number of T. argentea leaves. The correlation of the abundance of tending ants and Sternorrhyncha predators was positive with that of the sap-sucking Hemiptera, and the abundance of Sternorrhyncha predators was negative with that of tending ants and sap-sucking Hemiptera. The positive correlation between the abundance, richness, and diversity of insect groups and numbers of T. argentea leaves is an example of the bottom-up regulation mechanism, with the population dynamics of the lower trophic levels dictating those of higher trophic levels. The contribution of T. argentea, a host plant of many arthropods, to the recovery of ecological relationships between organisms in degraded ecosystems is important.

Ants evade harmful food by active abandonment.

Invasive ants, such as the Argentine ant, pose a severe economic and ecological threat. Despite advancements in baiting techniques, effectively managing established ant populations remains a daunting challenge, often ending in failure. Ant colonies employ behavioural immunity against pathogens, raising the question of whether ants can collectively respond to toxic baits. This study investigates whether ant colonies actively abandon palatable but harmful food sources. We provided two sucrose feeders, each generating a new foraging trail, with one transitioning to offering toxic food. Six hours later, ant activity on that path decreases, while activity on the non-toxic food and the trunk trail remains unaffected, excluding factors like population decline or satiation as reasons for the activity decline. Laboratory experiments confirmed that ants remained alive six hours after ingesting toxic food. Ant presence remains low on the toxic food path for days, gradually decreasing along the nearest section of the trunk trail. This abandonment behaviour minimises the entry of harmful food into the nest, acting as a protective social mechanism. The evasion of toxic bait-treated areas likely contributes considerably to control failures. Understanding the behavioural response to toxic baits is essential for developing effective strategies to combat invasive ant species.

Seed morphology and germination of Willd. ex Schult. emulating environmental conditions within ant nest.

Damiana (Turnera diffusa Willd. ex Schult.) is a species of plant used in traditional Mexican medicine for its aphrodisiac properties. Although it has a high commercial demand, both nationally and internationally, its sexual propagation is not usual due to the low percentage of seed germination. It has been proposed that ants play an important role in germination, due to the presence of elaiosomes. Therefore, the objectives of this study were to characterize the seed morphology of T. diffusa for agronomic purposes, analyze their viability, and evaluate their germination by simulating environmental conditions of an ant nest. For the morphological characterization, 30 seeds were selected and evaluated for the variables of color, size, and weight. Viability was evaluated with a tetrazolium test using two lots of seeds collected in 2016 and 2017, with different concentrations and three exposure times at 40°C. The germination of T. diffusa was evaluated under three pre-germination treatments and nine germination treatments. The results of the study showed that the seeds of T. diffusa have an average size of 0.725 mm long and 0.182 mm wide; the color of the seeds varies from brown to black when ripe and yellowish white when immature. There are no significant differences in the viability percentage (60%) for seeds collected in 2016 and 2017 (p = 0.20). On the other hand, there are significant differences between all the pre-germination and germination tests analyzed. Seeds of T. diffusa have the highest percentage of germination (36%) with the presence of elaiosome and 500 ppm of GA3. The germination interval of the seeds occurs over a period of six to 39 days. The application of GA3 in the germination of the seeds indicates that they present a physiological latency which was inhibited at concentrations of 500 and 300 ppm.

Simulated biomechanical performance of morphologically disparate ant mandibles under bite loading.

Insects evolved various modifications to their mouthparts, allowing for a broad exploration of feeding modes. In ants, workers perform non-reproductive tasks like excavation, food processing, and juvenile care, relying heavily on their mandibles. Given the importance of biting for ant workers and the significant mandible morphological diversity across species, it is essential to understand how mandible shape influences its mechanical responses to bite loading. We employed Finite Element Analysis to simulate biting scenarios on mandible volumetric models from 25 ant species classified in different feeding habits. We hypothesize that mandibles of predatory ants, especially trap-jaw ants, would perform better than mandibles of omnivorous species due to their necessity to subdue living prey. We defined simulations to allow only variation in mandible morphology between specimens. Our results demonstrated interspecific differences in mandible mechanical responses to biting loading. However, we found no evident differences in biting performance between the predatory and the remaining ants, and trap-jaw mandibles did not show lower stress levels than other mandibles under bite loading. These results suggest that ant feeding habit is not a robust predictor of mandible biting performance, a possible consequence of mandibles being employed as versatile tools to perform several tasks.

Plant species with larger extrafloral nectaries produce better quality nectar when needed and interact with the best ant partners.

Few studies have explored the phenotypic plasticity of nectar production on plant attractiveness to ants. Here, we investigate the role of extrafloral nectary (EFN) size on the productivity of extrafloral nectar in three sympatric legume species. We hypothesized that plant species with larger EFNs (i) have higher induced nectar secretion after herbivory events, and (ii) are more likely to interact with more protective (i.e. dominant) ant partners. We target 90 plants of three Chamaecrista species in the field. We estimated EFN size and conducted field experiments to evaluate any differences in nectar traits before and after leaf damage to investigate the phenotypic plasticity of nectar production across species. We conducted multiple censuses of ant species feeding on EFNs over time. Plant species increased nectar descriptors after leaf damage, but in different ways. Supporting our hypothesis, C. duckeana, with the largest EFN size, increased all nectar descriptors, with most intense post-herbivory-induced response, taking its place as the most attractive to ants, including dominant species. EFN size variation was an excellent indicator of nectar productivity across species. The higher control over reward production in plants with larger sized EFNs reflects an induction mechanism under damage that reduces costs and increases the potential benefits of indirect biotic defences.

Critical thermal limits and temperature-dependent walking speed may mediate coexistence between the native winter ant (Prenolepis imparis) and the invasive Argentine ant (Linepithemahumile).

Comparing the thermal tolerance and performance of native and invasive species from varying climatic origins may explain why some native and invasive species can coexist. We compared the thermal niches of an invasive and native ant species. The Argentine ant (Linepithema humile) is an invasive species that has spread to Mediterranean climates worldwide, where it is associated with losses in native arthropod biodiversity. In northern California, long-term surveys of ant biodiversity have shown that the winter ant (Prenolepis imparis) is the native species best able to coexist with Argentine ants. Both species tend hemipteran scales for food, and previous research suggests that these species' coexistence may depend on seasonal partitioning: winter ants are active primarily in the colder winter months, while Argentine ants are active primarily in the warmer months in northern California. We investigated the physiological basis of seasonal partitioning in Argentine and winter ants by a) measuring critical thermal limits, and b) comparing how ant walking speed varies with temperature. While both species had similar CTmax values, we found differences between the two species' critical thermal minima that may allow winter ants to remain functional at ecologically relevant temperatures between 0 and 2.5 °C. We also found that winter ants' walking speeds are significantly less temperature-dependent than those of Argentine ants. Winter ants walk faster than Argentine ants at low temperatures, which may allow the winter ants to remain active and forage at lower winter temperatures. These results suggest that partitioning based on differences in temperature tolerance promotes the winter ant's continued occupation of areas invaded by the Argentine ant.

Do bromeliads affect the arboreal ant communities on orange trees in northwestern Costa Rica?

Ants often interact with other invertebrates as predators or mutualists. Epiphytic bromeliads provide nesting sites for ants, and could increase ant abundances in the tree canopy. We surveyed ants in the foliage of orange trees that either hosted bromeliads or did not. To determine if observed associations between bromeliads and tree ants were causal, we removed bromeliads from half of the trees, and resurveyed ants six weeks later. Our results show that bromeliad presence is correlated with higher ant abundances and different species of ants on orange trees during the dry season. This increase in ant abundance was driven primarily by Solenopsis ants, which were both numerous and found to facultatively nest in bromeliads. Bromeliad removal did not affect either ant abundance or composition, potentially because this manipulation coincided with the transition from dry to wet season. Other ant species were never encountered nesting in bromeliads, and the abundances of such ants on tree leaves were unaffected by bromeliad presence or removal. Considering the importance of ants in herbivore regulation, our findings suggest that bromeliads-through their association with ants-could indirectly be associated with biological control in agricultural systems.

Nest architecture and colony composition in two populations of Ectatomma ruidum sp. 2 (E. ruidum species complex) in southwestern Colombia.

Nest architecture plays a fundamental role in the adaptation of ants to their habitat, favoring the action of economically important species. Ectatomma ruidum sp. 2 (ruidum species complex) is a biological control agent in Neotropical agroecosystems, exhibiting high bioturbation impact due to high nest densities. The architecture and composition of 152 nests were studied in two Andean populations of southwestern Colombia, 24 of them being cast using the paraffin wax technique. Nest entrance was a single, circular, 4 mm hole at ground level, without any special external structure, connected to a single vertical tunnel communicating with successive half ellipsoidal chambers. Nests were extremely shallow (depth range: 28.7-35.4 cm), with an average of six chambers and an overall volume of 92.2 cm3 per nest. The deeper the chamber, the smaller its volume. Nest building was independent of plants or roots, and no surface or underground physical connections were found between neighboring nests. Few nests possessed a queen, and neither ergatoids nor microgynes were recorded. Despite significant interactions between localities and the number of both males and workers, queen presence had an overall highly positive effect on the number of workers and larvae and a negative one on the number of gynes. Overall, the studied Colombian populations of E. ruidum sp. 2 retained the simple nest structure described for other species of this species complex and for colonies of the same species from other geographical areas, though they constrasted in their extreme shallowness. Our data suggest that E. ruidum sp. 2, at the local level, does not follow the usual monodomic pattern of this species with facultative polygyny but, rather, has a polydomic pattern with monogyny, perhaps related to the extreme shallowness of the nests due to soil structure, which could significantly enhance the queen's reproductive inhibition previously reported for this species.

Critical thermal limits in ants and their implications under climate change.

Critical thermal limits (CTLs) constrain the performance of organisms, shaping their abundance, current distributions, and future distributions. Consequently, CTLs may also determine the quality of ecosystem services as well as organismal and ecosystem vulnerability to climate change. As some of the most ubiquitous animals in terrestrial ecosystems, ants are important members of ecological communities. In recent years, an increasing body of research has explored ant physiological thermal limits. However, these CTL data tend to centre on a few species and biogeographical regions. To encourage an expansion of perspectives, we herein review the factors that determine ant CTLs and examine their effects on present and future species distributions and ecosystem processes. Special emphasis is placed on the implications of CTLs for safeguarding ant diversity and ant-mediated ecosystem services in the future. First, we compile, quantify, and categorise studies on ant CTLs based on study taxon, biogeographical region, methodology, and study question. Second, we use this comprehensive database to analyse the abiotic and biotic factors shaping ant CTLs. Our results highlight how CTLs may affect future distribution patterns and ecological performance in ants. Additionally, we identify the greatest remaining gaps in knowledge and create a research roadmap to promote rapid advances in this field of study.