Wasmannia Auropunctata Research Articles

Dominance of a highly invasive ant is limited to the nesting territory of its supercolony

Abstract Ant invasions represent a serious threat to biodiversity, agriculture and public health. Highly invasive ant species exhibit a very high abundance within its introduced range and cause severe impacts on native ant communities. This scenario tends to be different within the native range, where competitor ants may limit its access to food sources, thus its abundance. Here, we evaluated the competitive ability of a typical clonal and supercolonial native population of Wasmannia auropunctata (Roger) (Hymenoptera: Formicidae) in Argentina. We used a combination of pitfall traps and food baits to study the ant interactions within an assemblage where W. auropunctata coexists with another great invader, Solenopsis invicta (Buren) (Hymenoptera: Formicidae). The studied assemblage presented 56 ant species/morphospecies. Although W. auropunctata was the most abundant numerically, its ability to discover baits was intermediate, and its ability to recruit workers massively and monopolise baits was low. Wasmannia auropunctata was not successful defending baits nor attempting to usurp baits dominated by other species. Moreover, it lost all contests against S. invicta, one of the most ecologically dominant species in this assemblage. Wasmannia auropunctata dominated food sources only when they were located within the nesting territory of its supercolony. Within the native range, clonality and supercoloniality may favour the local numerical abundance of a highly invasive ant but may not be enough to achieve ecological dominance. This study sheds light on the important role of biotic interactions as a key factor that may limit the dispersal of invasive species.

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.

Establishment of a Microfluidic Chip Based Rapid Detection Method for <i>Wasmannia auropunctata</i>

Invasive alien ants are one of the most aggressive, competitive, and widespread invasive alien species around the world. <i>Wasmannia auropunctata, </i>native to the neotropical zoogeographic area, has been inadvertently introduced all over the world. The first disclosed record of field establishment of <i>W. auropunctata</i> in Chinese mainland was reported in 2022. In this paper, we aim to establish a rapid detection method targeting the <i>W. auropunctata </i>polymorphic microsatellite locus Waur-275, based on the microfluidic chip technology, to contribute to an active response to the crisis caused by this invasive pest. Eight primer sets were generated using the PrimerExplorer v5 online service, and the fifth primer set selected had the lowest Ct in the volume ratio of 8 (FIP/BIP:F3/B3). Method validity with six <i>W. auropunctata </i>samples confirmed the efficiency of this assay. High specificity was demonstrated by the positive result for <i>W. auropunctata</i> out of 6 related insect samples tested. Sensitivity analysis showed that this microfluidic chip method could achieve the detection limit of 1.00×10<sup>1</sup> copies/μL. A rapid screening method is essential for the whole process of interception and control of <i>W. auropunctata </i>in China. It can also help determine the origin of invasion, clarify the path of introduction to ensure biosecurity, and also uncover other possible undetected establishments in the wild.

Impacto de la hormiga invasora Wasmannia auropunctata (Roger, 1863) en la mirmecofauna local (Hymenoptera, Formicidae), seguimiento del área ocupada y una nueva población en España

In an urbanized area of the Eastern district of Marbella, and infested with the little fire ant Wasmannia auropunctata, the apparent exclusion of other ant species is described. By using baits arranged in seven infested transects and in six transects on their periphery, 14 non-Wasmannia species (12 genera) were recorded in the outer zone, while only one non-Wasmannia species was recorded in the infested zone. Wasmannia occupied 5.7 ha in 2018 and 16 ha in 2023. Benalmádena is added as a fourth municipality on the south Spanish coast in which that species has been detected.

Invasion alert for Wasmannia auropunctata: a potential distribution in southern China and associated invasion risk to urban, rural, agricultural, and forest lands

Invasion alert for Wasmannia auropunctata: a potential distribution in southern China and associated invasion risk to urban, rural, agricultural, and forest lands

Evidence of queen-rearing suppression by mature queens in the little fire ant, Wasmannia auropunctata.

The little fire ant (LFA), Wasmannia auropunctata, is a serious invasive pest first reported on Hawaii Island in 1999, and has since spread and established itself across the island. LFA is considered one of the worst 100 invasive species and has significant ecological, agricultural, and public health impacts in invaded areas, which include much of the tropical New World. Although localized eradication efforts have proven successful, they are intensive and difficult to implement. Furthermore, LFA's high invasive-ability resists these control efforts in areas where the species is established and can re-infest treated areas. This research set out to determine whether LFA queens have a suppressant effect on new queen production in nests, as a first step in identifying a potential queen pheromone for LFA. A queen pheromone could offer a means to shutdown LFA reproductive capability, potentially by suppressing the production of new queens or inducing the execution of queens or queen-destined larvae. When queenless experimental nests and polygyne experimental nests were compared, six out of eight queenless nests successfully reared both new alate queens (2.25 queens/nest) and drones (3.63 drones/nest) to adulthood, whereas only three of eight polygyne nests reared sexual larvae that failed to develop to adulthood or even the pupal stage. These results suggest that dealate mature LFA queens suppress the production of new alate queens in LFA nests, and is the first evidence that LFA may utilize a queen pheromone.

RNA virus discoveries in the electric ant, Wasmannia auropunctata

Despite being one of the most destructive invasive species of ants, only two natural enemies are known currently for Wasmannia auropunctata, commonly known as the electric ant or little fire ant. Because viruses can be effective biological control agents against many insect pests, including ants, a metagenomics/next-generation sequencing approach was used to facilitate discovery of virus sequences from the transcriptomes of W. auropunctata. Five new and complete positive sense, single-stranded RNA virus genomes, and one new negative sense, single-stranded RNA virus genome were identified, sequenced, and characterized from W. auropunctata collected in Argentina by this approach, including a dicistrovirus (Electric ant dicistrovirus), two polycipiviruses (Electric ant polycipivirus 1; Electric ant polycipivirus 2), a solinvivirus (Electric ant solinvivirus), a divergent genome with similarity to an unclassified group in the Picornavirales (Electric ant virus 1), and a rhabdovirus (Electric ant rhabdovirus). An additional virus genome was detected that is likely Solenopsis invicta virus 10 (MH727527). The virus genome sequences were absent from the transcriptomes of W. auropunctata collected in the USA (Hawaii and Florida). Additional limited field surveys corroborated the absence of these viruses in regions where the electric ant is invasive (the USA and Australia). The replicative genome strand of four of the viruses (Electric ant polycipivirus 2, Electric ant solinvivirus, Electric ant virus 1, and Solenopsis invicta virus 10 (in the electric ant) was detected in Argentinean-collected W. auropunctata indicating that the ant is a host for these viruses. These are the first virus discoveries to be made from W. auropunctata.

Interspecific competition predicts the potential impact of little fire ant Wasmannia auropunctata (Roger) (Hymenoptera: Formicidae) invasion on resident ants in southern China.

The little fire ant Wasmannia auropunctata (Roger) is a major invasive species that seriously threatens the biodiversity of invaded areas. W. auropunctata was first reported in Chinese mainland in 2022 and its impact on native species is still unknown. To evaluate the impact of W. auropunctata invasion on the ant communities in southern China, a series of interspecific competition experiments were conducted in this study. The individual aggression index and group aggression experiments showed the advantage of W. auropunctata in competition with 5 resident ants under equal worker numbers. When encountering Anoplolepis gracilipes, Camponotus nicobarensis, Tetramorium bicarinatum, Polyrhachis dives, and Solenopsis invicta, W. auropunctata gradually gained a competitive advantage with an increase in its number of workers. In the group aggression experiments with equal worker numbers, there was a negative correlation between the body length and mortality rate of resident ants. The results of the foraging behavior experiments showed that W. auropunctata was able to dominate food resources under competition with Carebara diversa, which also displayed weak competition in the group aggression bioassay. In addition, the abilities to recruit workers and retrieve food were inhibited under competition with S. invicta and T. bicarinatum. The results of the nesting behavior experiments showed that in the 24-h bout of space resource competition, W. auropunctata was dominant over C. diversa, S. invicta, and T. bicarinatum. The results of this study show that W. auropunctata has certain advantages in competition for food and space resources over resident ants in southern China, and some resident ant species may be replaced in the future.

One of the World’s Worst Invasive Alien Species Wasmannia auropunctata (Hymenoptera: Formicidae) Detected in Cyprus

Native to the Neotropics, Wasmannia auropunctata (Roger, 1863) has been unintentionally introduced around the world, heavily impacting native ant biodiversity, societies, and economies as well as human and animal health due to its potentially dangerous stings. Herein we report on the first record of W. auropunctata in Cyprus. Specimens were collected from plant nurseries and tourist facilities in Paphos and Limassol district. Wasmannia auropunctata is believed to spread via the horticultural pathway to locations with sufficient humidity. Further research is necessary to determine the distribution and assess possible negative impacts of W. auropunctata to native biodiversity, society, the economy and human health in Cyprus.

Monitoring the little fire ant, Wasmannia auropunctata (Roger 1863), in the early stage of its invasion in China: Predicting its geographical distribution pattern under climate change

Invasive alien ants (IAAs) are among the most aggressive, competitive, and widespread invasive alien species (IAS) worldwide. Wasmannia auropunctata, the greatest IAAs threat in the Pacific region and listed in “100 of the world’s worst IAS”, has established itself in many countries and on islands worldwide. Wild populations of W. auropunctata were recently reported in southeastern China, representing a tremendous potential threat to China’s agricultural, economic, environmental, public health, and social well-being. Estimating the potential geographical distribution (PGD) of W. auropunctata in China can illustrate areas that may potentially face invasion risk. Therefore, based on the global distribution records of W. auropunctata and bioclimatic variables, we predicted the geographical distribution pattern of W. auropunctata in China under the effects of climate change using an ensemble model (EM). Our findings showed that artificial neural network (ANN), flexible discriminant analysis (FDA), gradient boosting model (GBM), Random Forest (RF) were more accurate than categorical regression tree analysis (CTA), generalized linear model (GLM), maximum entropy model (MaxEnt) and surface distance envelope (SRE). The mean TSS values of ANN, FDA, GBM, and RF were 0.820, 0.810, 0.843, and 0.857, respectively, and the mean AUC values were 0.946, 0.954, 0.968, and 0.979, respectively. The mean TSS and AUC values of EM were 0.882 and 0.972, respectively, indicating that the prediction results with EM were more reliable than those with the single model. The PGD of W. auropunctata in China is mainly located in southern China under current and future climate change. Under climate change, the PGD of W. auropunctata in China will expand to higher-latitude areas. The annual temperature range (bio7) and mean temperature of the warmest quarter (bio10) were the most significant variables affecting the PGD of W. auropunctata in China. The PGD of W. auropunctata in China was mainly attributed to temperature variables, such as the annual temperature range (bio7) and the mean temperature of the warmest quarter (bio10). The populations of W. auropunctata in southern China have broad potential invasion areas. Developing strategies for the early warning, monitoring, prevention, and control of W. auropunctata in southern China requires more attention.

Horizon scanning for potential invasive non‐native species across the United Kingdom Overseas Territories

AbstractInvasive non‐native species (INNS) are recognized as a major threat to island biodiversity, ecosystems, and economies globally. Preventing high‐risk INNS from being introduced is the most cost‐effective way to avoid their adverse impacts. We applied a horizon scanning approach to identify potentially INNS in the United Kingdom Overseas Territories (OTs), ranging from Antarctica to the Caribbean, and from the Pacific to the Atlantic. High‐risk species were identified according to their potential for arrival, establishment, and likely impacts on biodiversity and ecosystem function, economies, and human health. Across OTs, 231 taxa were included on high‐risk lists. The highest ranking species were the Asian green mussel (Perna viridis), little fire ant (Wasmannia auropunctata), brown rat (Rattus norvegicus), and mesquite tree (Prosopis juliflora). Shipping containers were identified as the introduction pathway associated with the most species. The shared high‐risk species and pathways identified provide a guide for other remote islands and archipelagos to focus ongoing biosecurity and surveillance aimed at preventing future incursions.

Economic costs of invasive alien ants worldwide

Invasive ants are amongst the most destructive and widespread invaders across the globe; they can strongly alter invaded ecosystems and are responsible for the loss of native ant species. Several studies have reported that invasive ants can also lead to substantial economic costs. In this study, we search, describe and analyse 1342 reported costs of invasive ants compiled in the InvaCost database. Economic costs, reported since 1930 for 12 ant species in 27 countries, totalled US$ 51.93 billion, from which US$ 10.95 billion were incurred, and US$ 40.98 billion were potential costs (i.e., expected or predicted costs). More than 80% of total costs were associated with only two species, Solenopsis invicta and Wasmannia auropunctata; and two countries, the USA and Australia. Overall, damage costs amounted to 92% of the total cost, mainly impacting the agriculture, public and social welfare sectors. Management costs were primarily post-invasion management (US$ 1.79 billion), with much lower amounts dedicated to prevention (US$ 235.63 million). Besides the taxonomic bias, cost information was lacking for an average of 78% of the invaded countries. Moreover, even in countries where costs were reported, such information was available for only 56% of the invaded locations. Our synthesis suggests that the global costs of invasive ants are massive but largely biased towards developed economies, with a huge proportion of underreported costs, and thus most likely grossly underestimated. We advocate for more and improved cost reporting of invasive ants through better collaborations between managers, practitioners and researchers, a crucial basis for adequately informing future budgets and improving proactive management actions of invasive ants.

A global review of socioeconomic and environmental impacts of ants reveals new insights for risk assessment.

Risk assessments are fundamental to invasive species management and are underpinned by comprehensive characterization of invasive species impacts. Our understanding of the impacts of invasive species is growing constantly, and several recently developed frameworks offer the opportunity to systematically categorize environmental and socioeconomic impacts of invasive species. Invasive ants are among the most widespread and damaging invaders. Although a handful of species receives most of the policy attention, nearly 200 species have established outside their native range. Here, we provide a global, comprehensive assessment of the impacts of ants and propose a priority list of risk species. We used the Socioeconomic Impact Classification for Alien Taxa (SEICAT), Environmental Impact Classification for Alien Taxa (EICAT) and Generic Impact Scoring System (GISS) to analyze 642 unique sources for 100 named species. Different methodologies provided generally consistent results. The most frequently identified socioeconomic impacts were to human health. Environmental impacts were primarily on animal and plant populations, with the most common mechanisms being predation and competition. Species recognized as harmful nearly 20 years ago featured prominently, including Wasmannia auropunctata (little fire ant, electric ant), Solenopsis invicta (red imported fire ant), Anoplolepis gracilipes (yellow crazy ant), and Pheidole megacephala (African big-headed ant). All these species except W. auropunctata have been implicated in local extinctions of native species. Although our assessments affirmed that the most serious impacts have been driven by a small number of species, our results also highlighted a substantial number of less well publicized species that have had major environmental impacts and may currently be overlooked when prioritizing prevention efforts. Several of these species were ranked as high or higher than some of the previously recognized "usual suspects," most notably Nylanderia fulva (tawny crazy ant). We compared and combined our assessments with trait-based profiles and other lists to propose a consensus set of 31 priority species. Ever-increasing global trade contributes to growing rates of species introductions. The integrated approaches we used can contribute to robust, holistic risk assessments for many taxa entrained in these pathways.

Cytogenetic survey of eight ant species from the Amazon rainforest

The scarce information regarding ant diversity in the state of Amapá and lack of cytogenetic data of species from the Amazon region can hide ant biodiversity information that may be detectable with affordable cytogenetic techniques. In this study, we describe the karyotypes of eight ant taxa collected from Amazonian localities in French Guiana and Brazil. Chromosome numbers ranged from 2n = 18 to 2n = 68. The following chromosome numbers were observed for each species: Azteca sp. group chartifex 2n = 28; Dolichoderus bidens (Linnaeus, 1758) 2n = 18; Gnamptogenys tortuolosa (Smith, 1858) 2n = 44; Camponotus renggeri Emery, 1894 n = 20; Pseudomyrmex unicolor (Smith, 1855) 2n = 68 and n = 34; Apterostigma sp. pilosum complex 2n = 46; Odontomachus bauri Emery, 1892 2n = 44, and Wasmannia auropunctata (Roger, 1863) 2n = 32. The karyotypes of P. unicolor, G. tortuolosa, and O. bauri are reported here for the first time. Our data enabled comparisons between chromosomal data of some species from Amazon and Atlantic rainforests. We also highlight the methods used for the ant chromosome classification.

Behavioral flexibility in Wasmannia auropunctata (Hymenoptera: Formicidae).

Worker division of labor is a defining trait in social insects. Many species are characterized by having behavioral flexibility where workers perform non-typical tasks for their age depending on the colony’s needs. Worker division of labor and behavioral flexibility were examined in the little fire ant Wasmannia auropunctata (Roger, 1863), for which age-related division of labor has been found. Young workers perform nursing duties which include tending of brood and queens, and colony defense, while older workers forage. When nurses were experimentally removed from the colony, foragers were observed carrying out nursing and colony defense duties, yet when foragers were removed nurses did not forage precociously. We also administered juvenile hormone analog, methoprene, to workers. When methoprene was applied, foragers increased their nursing and defense activities while nurses became mainly idle. The behavioral flexibility of foragers of the little fire ant may be evidence of an expansion of worker’s repertoires as they age; older workers can perform tasks they have already done in their life while young individuals are not capable of performing tasks ahead of time. This may be an important adaptation associated with the success of this ant as an invasive species.

Differential effects of ants as biological control of the coffee berry borer in Puerto Rico

Conservation biological control consists of managing agroecosystem to maintain and enhance the action of natural enemies. Agroforestry systems such as shaded coffee system has been shown to maintain high diversity of organisms, including predators and parasitoids of insect pest. The coffee berry borer (CBB), Hypothenemus hampei, is one of the most widely distributed coffee pests frequently causing severe economic damage. Ants have been reported as natural enemies of the CBB, but different species of ants are known to have different and sometime contrasting effects against the CBB. In this study, we examine the damage and survival of CBB on coffee plants that are dominated by six different species of ants, Solenopsis invicta, Wasmannia auropunctata, Monomorium floricola, Paratrechina longicornis, Brachymyrmex heeri and Pheidole moerens, in Puerto Rico. This represents a novel community of natural enemies since four of the six species are non-native. We hypothesized that the large and dominant species, S. invicta, would reduce the damage of the CBB by preying on adult CBB outside the berries, while the smaller species, would reduce the survival of the CBB by preying on the reproducing adults inside the berries (and potentially also on the immature stages, although not quantified in this study). Results show that S. invicta was associated with significantly reduced CBB damage. The only species associated with reduced survival of CBB inside berries was W. auropunctata, whereas the others were not associated with any effect on survival. Surprisingly, P. moerens and P. longicornis had a significant positive effect on the damage of the CBB suggesting that these species could only forage on plants that did not harbor S. invicta or W. auropunctata, the two most aggressive ants both of which were associated negatively with the CBB. The study also suggests that the negative impact of S. invicta on W. auropunctata indirectly facilitates the CBB by protecting it from predation by W. auropunctata once the adult CBB gains entrance to the coffee berry.

A Regional Approach Shows Differences Among Invasive Ants Solenopsis geminata and Wasmannia auropunctata (Hymenoptera: Formicidae) Within Its Native Range of Distribution.

Worldwide, two of the most harmful invasive ants typical of disturbed sites are Solenopsis geminata (Fabricius) and Wasmannia auropunctata (Roger). Both are natives of the Neotropics and are widely distributed all over the tropics. Within its original geographic range, there are few data on its abundance and potential damage to natural ecosystems. In this study, we recorded their abundance and relationships to diversity and richness of soil ant communities in two localities with different amount of forested area (López Mateos, LM 77% and Venustiano Carranza, VC 27%), at Los Tuxtlas reserve. In each locality, four land use systems (LUS) were sampled: tropical rain forests, agroforestry plantations, annual crops, and pastures. Data were gathered from 360 ant samples obtained from litter squares, pitfall traps, and soil monoliths in 40 sampling points (20 per locality, and five per LUS). Solenopsis geminata was more abundant in LM than in VC; the opposite trend was observed for W. auropunctata. In LM, S. geminata was more abundant in crops than in the other LUS, whereas W. auropunctata tended to have higher abundances in less managed sites of both localities. Abundance and species richness of ant communities were higher in LM than in VC. At regional and local levels, we found negative relationships between the abundance of S. geminata and species richness; the inverse pattern was found for W. auropunctata. We conclude that at Los Tuxtlas, W. auropunctata can be considered as a typical dominant native species, whereas S. geminata is the common exotic invasive ant.

Little Fire Ant Wasmannia auropunctata (Roger) (Insecta: Hymenoptera: Formicidae)

The Featured Creatures collection provides in-depth profiles of insects, nematodes, arachnids and other organisms relevant to Florida. These profiles are intended for the use of interested laypersons with some knowledge of biology as well as academic audiences. The little fire ant, Wasmannia auropunctata (Roger), is a problematic invasive species from Central and South America that has become established in numerous countries and on islands around the world. This species has been documented in the state of Florida since at least 1924, where it was first recorded in Miami (Wetterer and Porter 2003). As the common name little fire ant (LFA) suggests, stings are painful, especially in relation to their small size.

Effects of the Invasive Little Fire Ant (Wasmannia auropunctata) on Ant Community Composition on UF Campus

Invasive species are a serious threat to Florida’s native ecosystems and can have significant economic impacts. The invasive little fire ant (Wasmannia auropunctata) was first observed on the University of Florida’s campus in the Field and Fork Gardens in Summer 2018 and a targeted eradication of this population began in Fall 2018. This project aimed to compare ant community composition in invaded and uninvaded areas to better understand how ant invasions affect native ant communities. For comparison with Field and Fork Gardens invaded sites, four additional sites on UF’s campus were surveyed for ants through leaf litter sampling. Samples were sorted and all ants identified to the genus level; samples from invaded sites were identified to species. In samples from invaded sites, the community had lower species richness and a lower relative abundance of ant species compared to uninvaded communities. Determining how the invasion of the little fire ant affects ant communities is important as invasive ants do not fill the same ecosystem roles as native ants, such as seed dispersal and mutualist interactions. Data on community composition in uninvaded areas could be useful in efforts to restore a site after eradication has been achieved.

Using Behavioral Experimentation to Understand the Social Structure of the Little Fire Ant (Wasmannia auropunctata) in Florida

Wasmannia auropunctata (LFA) is a small, yellow ant that is native to the Central and South America that has become a globally invasive species by acting as an agricultural pest in addition to being ecologically destructive in non-native regions. One trait thought to contribute to successful invasion of ants is unicoloniality, which is characterized by lack of aggression among workers and queens from different colonies. This results in colonies becoming effectively borderless, expanding as a single, massive colony across large geographic distance. These ants are known to be unicolonial in some parts of their range, but no studies to date have assessed unicoloniality in Florida populations. To determine whether LFA populations across Florida were members of a unicolonial lineage, we carried out integration trials using 27 colonies from 6 sites in 3 Florida counties. Approximately 20 workers from different colonies were placed together in an arena; after 24 hours they were evaluated to determine whether or not they integrated. Out of a total of 42 trials, 17 (40%) resulted in full integration and 25 (60%) did not. Colonies that were collected within 9 km of each other integrated, and ants from colonies beyond that distance did not integrate. These results suggest that the little fire is not unicolonial in Florida on a large scale, but perhaps on a smaller scale. Future studies should attempt to use colonies from more counties and incorporate genetic data to determine relatedness among these ants.