Native Ants Research Articles

New crop, new pest, old ants: Crop colonisation by native ants disrupt biological control of an invasive mealybug in Mediterranean persimmon

Abstract Crop expansion is generally followed by an increase of herbivores. Some of these herbivore species can be favoured by mutualisms with ants that can also colonise introduced crops. Here, we hypothesized that the invasive mealybug Pseudococcus longispinus has established mutualistic relationships with native or exotic ants in Mediterranean persimmon crop. This relationship could negatively impact mealybug natural enemies and facilitate the colonisation of this new crop by the mealybug. To test this hypothesis, we sampled 17 persimmon orchards from the main producing area of the Mediterranean basin across two consecutive years and three different seasons. We identified the ant complex attending Ps. longispinus, calculated the ant attendance ratios and assessed the density dependence between tending ants and Ps. longispinus at mealybug colony level. Finally, we evaluated the effect of ants on the density of Ps. longispinus and its natural enemies at tree level. Fifteen ant species were found foraging in persimmon trees, out of which 11 attended Ps. longispinus colonies. The Mediterranean native species Lasius grandis, Pheidole pallidula and Plagiolepis spp. were the most abundant ant species in the canopies, and La. grandis was the most abundant species attending Ps. longispinus. This ant tended to attend large colonies of the mealybug in spring and summer. Pseudococcus longispinus density was positively correlated with ant activity in persimmon trees, which can be partially explained by the negative effect of ants on the mealybug parasitism and the density of potential predators. This study suggests that the density and damage caused by Ps. longispinus in Mediterranean persimmon are exacerbated by the attendance of native ants that disrupt mealybug biological control. Our results reinforce the hypothesis that ant attendance is a driving factor determining the density of honeydew‐producing herbivores and highlight that native ant species may facilitate the establishment and spread of exotic honeydew‐producing pests in new crops.

Discovering Native Ant Species with the Potential to Suppress Red Imported Fire Ants.

Native ants have long been considered for their potential to suppress the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), a highly invasive and destructive species. However, the knowledge in this field is limited to behavioral observations of a few related native ants. In this study, by setting up a series of ant combinations of three native ants, i.e., Monomorium chinense Santschi, the robust crazy ant Nylanderia bourbonica Forel, and Iridomyrmex anceps Roger, with S. invicta, we observed the aggression levels and mortality rates. Using baited vials, we also investigated the abundance of native ants in four types of habitats in Eastern China that are preferred by S. invicta (woodland, green belts on roadsides, grassland, and farmland), as well as their seasonal abundance when co-existing with S. invicta and their spatial distribution before and after control of S. invicta. We found that M. chinense and N. bourbonica show a degree of aggression towards S. invicta and can kill substantial proportions of S. invicta under laboratory conditions, but I. anceps does not. Both M. chinense and N. bourbonica can occur in each type of habitat investigated and are more abundant in green belts (particularly lawns with turf) and grasslands relative to other habitats. In grasslands with S. invicta, M. chinense maintained a low density before early July; however, its abundance increased thereafter and reached a peak in September. N. bourbonica also had a low density early in the season and increased steadily from April. Its abundance began to decrease substantially from November. In grasslands invaded by S. invicta, both M. chinense and N. bourbonica were restricted to sites close to the margins before S. invicta was controlled; however, they spread to a larger range within a few weeks after control of S. invicta. In conclusion, M. chinense and N. bourbonica have the potential to suppress S. invicta invasion in habitats that are abundant with these two native ants.

La última búsqueda de E.O. Wilson: ¿hay hormigas en las Islas Malvinas?

The Falkland Islands constitute a remote archipelago in the South Atlantic Ocean that is about 450 km east of continental South America. The invertebrate fauna of the Falkland Islands is poorly known, and thus far no ants have been reported. We conducted surveys for ants on East Falkland Island during the austral summer 2019. No ants were found during our surveys, such that East Falkland Island is one of few oceanic islands that lack native and non-native ants.

Impact of temperature and season on ant foraging activity of two invasive species in a Mediterranean urban area

Abstract Invasive species often have harmful effects on human activities and biodiversity. The Tapinoma nigerrimum complex includes three species that exhibit invasive traits and the ability to form supercolonies, including Tapinoma magnum and Tapinoma darioi. While these species are native to the Mediterranean basin, they have recently been reported as invasive in more northern regions of Europe. However, T. magnum and T. darioi show different invasion patterns in Europe, suggesting differences in thermal preferences between these species. We aimed to determine whether there was any difference in activity pattern depending on temperature or season between the two Tapinoma species and between Tapinoma and co‐occurring native Mediterranean ants. We measured ambient temperature and ant foraging activity around the nest entrances of T. darioi and T. magnum in urbanised sites around Montpellier, southern France, over almost 1 year. We did not detect differences in activity between the two species according to temperature, but T. magnum was more active than T. darioi in winter. Compared to the co‐occurring native species, the two Tapinoma species were more active at low temperatures and earlier in the year. These results suggest that the difference in invasion success between T. magnum and T. darioi may not be explained by temperature preference. The difference in activity between native Mediterranean species and invasive Tapinoma suggests a coexistence through niche partitioning. In addition, our results suggest that control measures against invasive Tapinoma species would be more effective if applied at the end of winter.

Do Dominant Native Ants Outcompete the Invasive Argentine Ant in Mediterranean Citrus Ecosystems? A Laboratory Test.

The invasive Argentine ant (Linepithema humile) poses a significant threat to ecosystem stability worldwide. In Mediterranean citrus ecosystems, its spread may be limited by interactions with dominant native ant species. We conducted laboratory experiments to investigate the competitive dynamics between Argentine ants and two major native species, Tapinoma nigerrimum and Lasius grandis. At the individual level, both native species exhibited superior competitive performance, attributed to their larger body sizes and potential differences in chemical defences. At the colony level, T. nigerrimum demonstrated efficiency in interference competition, successfully defending food resources from Argentine ants. However, the Argentine ant exhibited higher recruitment capacity, albeit it was density-dependent. Our findings support the hypothesis that dominant native ants can serve as barriers against Argentine ant invasion in citrus ecosystems, highlighting the importance of interspecific competition in shaping community dynamics and invasive species management. This study underscores the potential role of native ant species in mitigating the impacts of invasive ants on ecosystem functioning and biodiversity conservation in agricultural landscapes, offering valuable insights for invasive species management strategies in Mediterranean citrus ecosystems.

Misapplied management makes matters worse: Spatially explicit control leverages biotic interactions to slow invasion.

A wide range of approaches has been used to manage the spread of invasive species, yet invaders continue to be a challenge to control. In some cases, management actions have no effect or may even inadvertently benefit the targeted invader. Here, we use the mid-20th century management of the Red Imported Fire Ant, Solenopsis invicta, in the US as a motivating case study to explore the conditions under which such wasted management effort may occur. Introduced in approximately 1940, the fire ant spread widely through the southeast USand became a problematic pest. Historically, fire ants were managed with broad-spectrum pesticides; unfortunately, these efforts were largely unsuccessful. One hypothesis suggests that, by also killing native ants, mass pesticide application reduced competitive burdens thereby enabling fire ants to invade more quickly than they would in the absence of management. We use a mechanistic competition model to demonstrate the landscape-level effects of such management. We explicitly model the extent and location of pesticide applications, showing that the same pesticide application can have a positive, neutral, or negative effect on the progress of an invasion, depending on where it is applied on the landscape with respect to the invasion front. When designing management, the target species is often considered alone; however, this work suggests that leveraging existing biotic interactions, specifically competition with native species, can increase the efficacy of management. Our model not only highlights the potential unintended consequences of ignoring biotic interactions, but also provides a framework for developing spatially explicit management strategies that take advantage of these biotic interactions to work smarter, not harder.

Native ants vary in their use of seeds from a recently introduced myrmecochorous exotic plant

AbstractMyrmecochory is a common mutualism between ants and plants benefiting both partners: ants obtain a nutrient-rich food source, while plants enjoy a host of benefits ranging from enhanced dispersal to protected germination sites. However, this mutualism can be exploited by invasive myrmecochores, where native ants spread invasive plant seeds, possibly to the detriment of native plant assemblages. With the recent introduction of a potentially invasive myrmecochorous plant (Thesium ramosum) in Alberta, Canada, we tested ant interest in T. ramosum. To evaluate both general interest in T. ramosum as a food source, and preference for T. ramosum over other food sources, we collected colonies of four commonly occurring native Formica species and conducted seed removal trials and food preference trials. We then evaluated interest in and preference for T. ramosum seeds through assessing mean rate of seed removal and food item removal, total number of seeds and food items removed, and trends in seed and food item removal through time. We found that while all ant species tested showed interest in T. ramosum, interest level varied among species, and additional factors such as colony size and presence of host species in socially parasitic species influenced interest in T. ramosum. Considering native ant interest in T. ramosum as a food source, it seems plausible that Formica species may act as a dispersal vector for T. ramosum, potentially enhancing its invasiveness.

Ant community composition in a citrus grove reveals eastern expansion in Florida of the South American big-headed ant (Hymenoptera: Formicidae)

Abstract Florida has become a worldwide hotspot for introduced and invasive ants (Hymenoptera: Formicidae). Furthermore, studies have shown that non-native ants support other invasive insects in Florida, such as the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), which is the vector of Candidatus Liberibacter asiaticus, the causal pathogen of citrus greening, the worst citrus disease in the world. The Asian citrus psyllid establishes beneficial interactions with invasive, introduced, and native ants. In this study, we described the ant diversity in a citrus grove in south Florida as a first step to assess ant-Asian citrus psyllid interactions for future studies. During the summer of 2018, 25 pitfall traps were set in a citrus grove. The red imported fire ant, Solenopsis invicta (Buren), was present in all the traps (100 %), and 19 traps (76 %) had Dorymyrmex bureni (Trager), the pyramid ant, which is native to the southeast United States. Two introduced ants, Cardiocondyla emeryi (Forel) and Brachymyrmex obscurior (Forel), were found in 15 (60 %) and 11 (44 %) traps, respectively. The South American big-headed ant, Pheidole obscurithorax (Naves), was found in 14 traps (56 %). This introduced ant has been found to co-exist with S. invicta, and to our knowledge, this is the first report of the species in this eastern part of peninsular Florida. Finally, Cardiocondyla venustula (Wheeler), an introduced ant from Africa, was found in one of the traps. Although, this ant is found in south Florida, it seems uncommon, and this is its first report in this county. Our study highlights the continued spread of introduced and invasive ants in Florida.

Disruption of an ant-plant mutualism shapes interactions between lions and their primary prey.

Mutualisms often define ecosystems, but they are susceptible to human activities. Combining experiments, animal tracking, and mortality investigations, we show that the invasive big-headed ant (Pheidole megacephala) makes lions (Panthera leo) less effective at killing their primary prey, plains zebra (Equus quagga). Big-headed ants disrupted the mutualism between native ants (Crematogaster spp.) and the dominant whistling-thorn tree (Vachellia drepanolobium), rendering trees vulnerable to elephant (Loxodonta africana) browsing and resulting in landscapes with higher visibility. Although zebra kills were significantly less likely to occur in higher-visibility, invaded areas, lion numbers did not decline since the onset of the invasion, likely because of prey-switching to African buffalo (Syncerus caffer). We show that by controlling biophysical structure across landscapes, a tiny invader reconfigured predator-prey dynamics among iconic species.

In vitro Studies on the Biology and Predatory Potential of Commonly Occurring Ant Species in a Selected Agro-ecosystem of the Himalayan Range, India

Four commonly occurring species of queen ants were collected after their nuptial flight from an agroecosystem in Lehri Sarail village of Himachal Pradesh (31°32’03.9”N 76°38’57.7“E) using light traps. Queens named HAC1, HAC2, HAC3, and HAC4 were placed individually in a test tube with water sources. Once the queen started laying eggs, and a few workers emerged, they were transferred to an artificial formicarium. HAC1 and HAC2 were identified as Camponotus compressus, while HAC3 and HAC4 were identified as Polyrhachis thompsoni and Pheidole minor, respectively. In the study period of one year between July 2020 and July 2021, offspring from all colonies were found to be workers. HAC1, HAC2, and HAC4 produced dimorphic workers, the majors and minors. Studies on colony establishment, biology, and behavior were carried out with colonies from HAC1, HAC2, and HAC3, while a colony from HAC4 failed to establish. All species showed similar types of colony founding, nesting, brood management, necrophorosis, and hibernation. C. compressus showed higher fecundity, while percent hatchability was higher in P. thompsoni. Percent pupation and adult emergence were higher in C. compressus and lower in P. thompsoni. P. thompsoni was observed to be more aggressive with a high predation rate, followed by C. compressus. P. minor showed aggressiveness initially but was unable to incapacitate the host larva. Understanding ant biodiversity, biology, behavior, predatory potential, etc., will allow us to use the native ants in the agroecosystem as biological control agents. Methods of rearing ants under the artificial setup described here enable laboratory culturing of ants with biocontrol potential and using ants as model organisms to study the bio-efficacy of agrochemicals and pharmaceutical drugs.

Warming promotes non‐native invasive ants while inhibiting native ant communities

Abstract1. Non‐native species may be the cause of native species declines or an effect of habitat degradations that promote the former and damage the latter. Social insects are extraordinarily successful organisms, and non‐native social insects, such as ants, often are very successful invaders of novel habitats.2. The red imported fire ant (Solenopsis invicta) and the Asian needle ant (Brachyponera chinensis) are widespread non‐native invaders in the eastern United States that bring ecological, economic and social impacts, but their putative effects on native ant communities may be concomitant with habitat degradation rather than inherent in their invasion.3. Given this gap in understanding, our goal was to examine how experimental warming influenced native and non‐native ant communities. Specifically, we hypothesised that (a) non‐native ant abundance and species richness will increase in warmed plots and that (b) warming‐induced increases in the non‐native ant populations will correspond with decreases in native ant abundance and species richness.4. To test these hypotheses, we used three levels of experimental forest edge soil warming (warming targeted at +0, +3, and +5°C above ambient soil temperature) in a mixed deciduous forest in the Georgia (USA) Piedmont. We used repeated pitfall trapping to investigate how the experimental warming influenced the composition of native and non‐native ant communities with a focus on how warming combined with S. invicta and B. chinensis invasion impacted native ant communities.5. Our results suggest that experimental warming promoted the non‐native invasive ants, particularly S. invicta and B. chinensis. We also found that B. chinensis somewhat inhibited native ant communities, but not because of warming. The warmed environment benefited both non‐native invasive ants at the expense of native ants but, given that B. chinensis negatively impacted the native ants with far fewer workers than S. invicta, B. chinensis may pose a greater threat to native ant communities than S. invicta in a warmer world.

Tree canopy cover and elevation affect the distribution of red harvester ant nests in a peri-urban setting.

With an increase in human population over the past 30 years, regional land use in south Texas has shifted from grassland and shrubland to a peri-urban matrix. Despite this shift from natural areas to more anthropogenically modified habitats, native red harvester ants (Pogonomyrmex barbatus) have maintained nest sites within parts of these matrices. To determine which habitat characteristics in a peri-urban landscape may play a role in red harvester ant nest site selection, we mapped the location of nests in 2020 and 2021. We then evaluated nest presence and absence relative to elevation, percentage of surrounding impervious surfaces, distance to roadways, and tree canopy cover (using NDVI). For a sub-sample of the study site, we also measured soil moisture and estimated the potential foraging area per colony with Voronoi tessellation. We found that nests were clustered together near high human-use areas such as athletic fields, lawns, sidewalks, and railroad tracks. Nests were more likely to be found in areas with higher elevation and lower tree canopy cover, with no impact from surrounding impervious surfaces or soil moisture. In fact, many nests were observed immediately adjacent to roadways and in paved parking lots. Red harvester ants are highly adept at nesting in disturbed, urbanized matrices, but still appear to be constrained by certain environmental factors like shading, potential flood risk (elevation), and access to food resources (foraging area).

Native ants facilitate the invasion by Delottococcus aberiae in Mediterranean citrus

Native ants facilitate the invasion by Delottococcus aberiae in Mediterranean citrus

Interaction and resource exploitations between invasive and native ants in cocoa and surronding farmlands in southern Cameroon rainforest

Interaction and resource exploitations between invasive and native ants in cocoa and surronding farmlands in southern Cameroon rainforest

First evidence of ants (Hymenoptera, Formicidae) in the early Pleistocene of Madeira Island (Portugal)

ABSTRACT To be successfully established on oceanic islands, native ants (Hymenoptera: Formicidae) have to migrate from the mainland or from nearby islands, crossing the ocean barriers, to find a suitable habitat. Despite the general interest on oceanic islands biotas, nothing is known about the deep-time migration and settling of native ants in these insular ecosystems. Palaeoentomological studies on oceanic islands that could provide palaeobiological information on Formicidae are scarce. Here, we describe and illustrate the first fossil of an ant from the Macaronesian archipelagos (Atlantic Ocean), based on a partial forewing found within 1.3 Ma (Calabrian, Pleistocene) lacustrine sediments from Madeira Island, Portugal. Although unidentifiable beyond the family level, this fossil record provides a minimum age for the presence of ants in the Madeira archipelago. Palaeoecologically, this record indicates the presence of suitable habitats for ants during the early Pleistocene.

Global change drivers synergize with the negative impacts of non-native invasive ants on native seed-dispersing ants

Global change drivers synergize with the negative impacts of non-native invasive ants on native seed-dispersing ants

Chemical identification of an active component and putative neural mechanism for repellent effect of a native ant's odor on invasive species.

The invasive Argentine ants (Linepithema humile) and the red imported fire ants (Solenopsis invicta) constitute a worldwide threat, causing severe disruption to ecological systems and harming human welfare. In view of the limited success of current pest control measures, we propose here to employ repellents as means to mitigate the effect of these species. We demonstrate that cuticular hydrocarbons (CHCs) used as nestmate-recognition pheromone in the Japanese carpenter ant (Camponotus japonicus), and particularly its (Z)-9-tricosene component, induced vigorous olfactory response and intense aversion in these invasive species. (Z)-9-Tricosene, when given to their antennae, caused indiscriminate glomerular activation of antennal lobe (AL) regions, creating neural disarray and leading to aversive behavior. Considering the putative massive central neural effect, we suggest that the appropriate use of certain CHCs of native ants can facilitate aversive withdrawal of invasive ants.

Native European ants can discourage host colonization and reduce reproductive success of the invasive ambrosia beetle Xylosandrus compactus

Due to their ubiquity and their nature as generalist predators, ants have long been used as biological control agents in forest and agricultural systems. Several exotic ambrosia beetles (Coleoptera: Curculionidae: Scolytinae, Platypodinae) are considered emerging widespread pests of various trees and shrubs growing in forests, nurseries, orchards, and urban areas. Among them, the Scolytinae Xylosandrus compactus (Eichhoff) is an invasive fungus-farming species native to Asia and able to cause serious damage to a broad range of natural and cultivated plants worldwide, exerting significant ecological and economic costs. Its biology makes conventional control strategies often ineffective, while little is known about natural enemies. We explored the potential of native European predators as natural enemy of this pest, conducting laboratory tests with four widespread ant species using chestnut and laurel as beetle hosts. In particular, we evaluated the interactions between X. compactus and four species of native Euro-Mediterranean ants that usually forage on plants: Crematogaster scutellaris (Olivier), Tapinoma magnum Mayr, Temnothorax affinis (Mayr), and Temnothorax mediterraneus Ward, Brady, Fisher & Schultz. Results indicate that ants may significantly limit the reproductive success of X. compactus, increasing the mortality of the beetle foundresses and reducing their offspring. Smaller ant species may also invade X. compactus nests, killing larvae, pupae and adults, while female beetles avoid nesting in twigs previously visited by ants. These results encourage to explore possible applications of ants in the biological control of X. compactus and the ecological implications of these interactions in the field.

Non‐native stinging ant interactions with native anurans

AbstractNative predators may ignore or avoid non‐native prey because they do not recognize the novel organisms as food, or the invasive prey may bring antipredatory defences against which the native predators have not co‐evolved a sufficient attack. Non‐native ants successfully invade novel habitats worldwide and, in eastern North America, several invasive ant species bring venomous stings in quantities that far exceed that of native ant species. Ants make up a considerable portion of anuran diets, and we investigated how several native anurans reacted to the invasion of the non‐native European fire ant (Myrmica rubra). Myrmica rubra has a venomous sting, and it occurs in aggressive swarms that can deliver multiple stings. Despite these defences, based on field observations, we expected that leopard frogs (Lithobates pipiens) might consume the abundant ants. We also predicted that habitat niche differences from the moisture‐dependent ants would limit consumption by the more terrestrial American toads (Anaxyrus americanus) and more aquatic green frogs (Lithobates clamitans). Our results suggested that none of the anuran species make use of the M. rubra swarms. The anurans, particularly A. americanus, consumed ample native ants in the field, but not M. rubra ants. In the laboratory, A. americanus ate several M. rubra ants, and L. pipiens a few, but experienced anuran individuals collected from M. rubra‐invaded habitat were less likely to eat the ants in laboratory. Hence, at best, M. rubra invasion appears to supplant rather than supplement anuran food resources.

Avoidance of invasive prey reduces subsequent consumption of similar native prey

Learned avoidance of invasive species could carry over to ecologically similar non-threatening native taxa, altering predator-prey interactions and food webs. The red imported fire ant, Solenopsis invicta, is an invasive prey of the eastern fence lizard, Sceloporus undulatus. Despite potentially lethal outcomes, juvenile fence lizards innately consume fire ants; however, they rapidly learn to avoid eating them with early-life exposure. Ants comprise a large portion of fence lizards' diets and a generalized avoidance of ants could thus reduce their prey pool. We tested whether learned avoidance following exposure to invasive fire ants would reduce the subsequent consumption of a palatable native ant. Lizards that consumed invasive fire ants for five days were less likely to subsequently consume native common pyramid ants, Dorymrymex bureni, than were lizards that initially consumed these non-threatening native ants. Our results suggest that learned avoidance of invasive prey can carry-over to avoidance of palatable native prey. The broad avoidance of native ants, due to the presence of invasive fire ants, could potentially increase native ant populations affecting their predators and competitors.