Research Articles

Potential range expansion of the red imported fire ant (Solenopsis invicta) in China under climate change

  • WANG Huanjiong , 1 ,
  • WANG Hui 1 ,
  • TAO Zexing 1, 2 ,
  • GE Quansheng , 1, *
  • 1. Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China
  • 2. University of Chinese Academy of Sciences, Beijing 100049, China
Corresponding author:Ge Quansheng, Professor, E-mail:

Author: Wang Huanjiong: Associate Professor, specialized in climate change and biometeorology. E-mail:

Received date: 2017-06-12

  Accepted date: 2017-11-16

  Online published: 2018-12-20

Supported by

National Key Research and Development Program of China, No.2016YFC1201302


Journal of Geographical Sciences, All Rights Reserved


The red imported fire ant (RIFA, Solenopsis invicta), a notorious invasive insect, has received considerable attention owing to its impacts on native biodiversity, agriculture, and human health. Under global warming, the inhabitable area of the RIFA may be enlarged. However, few studies have focused on the potential range expansion of the RIFA in East Asia. Using a process-based physiological model, we simulated the potential range of the RIFA in China based on gridded temperature datasets for the current (2004-2012) and future (2090-2100) climates under Representative Concentration Pathway (RCP) 4.5 and RCP 8.5. It was found that the southeastern part of China (below 32°N) is suitable for RIFA proliferation. The present distribution area of the RIFA corresponds well with the potential range simulated by the model. In the RCP 4.5 and RCP 8.5 warming scenarios, the inhabitable area of the RIFA along the northern boundary would on average extend 101.3±85.7 (mean±SD) and 701.2±156.9 km, respectively, by the end of the 21st century. Therefore, future climate change would significantly affect the inhabitable area of the RIFA. Our results provide the basis for local quarantine officials to curtail accidental introductions of this insect, especially in the certain and possible infestation zones.

Cite this article

WANG Huanjiong , WANG Hui , TAO Zexing , GE Quansheng . Potential range expansion of the red imported fire ant (Solenopsis invicta) in China under climate change[J]. Journal of Geographical Sciences, 2018 , 28(12) : 1965 -1974 . DOI: 10.1007/s11442-018-1574-x

1 Introduction

Biological invasions can cause severe impacts on ecosystem services worldwide through their effects on biodiversity and ecosystem processes (Simberloff et al., 2013). As one of the world’s worst invasive alien species listed in the Global Invasive Species Database (, the red imported fire ant (RIFA) (Solenopsis invicta) has probably received more attention than any other invasive insect due to its impact on native biodiversity (Kenis et al., 2009). The RIFA may cause reductions in the diversity and abundance of native ants (Cook, 2003; Lu et al., 2012). They also compete with and prey upon a variety of other organisms, and may enter into or disrupt mutualistic interactions with numerous plants and other insects (Holway et al., 2002; Wickings and Ruberson, 2016). Parks, recreational areas, and cropland may become unsafe following an invasion by the RIFA because their sting can cause an allergic reaction (DeShazo et al., 1999). The economic costs imposed by the RIFA amount to millions of dollars annually in specific regions (Teal et al., 1999; Gutrich et al., 2007).
Originating from South America, the RIFA was introduced to the USA by ships that carried agricultural goods and earth ballast in the 1930s (Vinson, 1997). It is now found in 13 states of the southeastern USA (Mikheyev and Mueller, 2006). In Australia and New Zealand (Sutherst and Maywald, 2005; Wylie et al., 2016), the RIFA was first found in 2001. Subsequently, it was introduced to Taoyuan City, Taiwan, China in 2003 (Chen et al., 2006) and Wuchuan County, Guangdong Province, China, in 2004 (Zeng et al., 2005). By 2014, the RIFA had been reported in nine provinces of Chinese mainland according to the Ministry of Agriculture of China. Thus, controlling the spread of the RIFA has become a global concern.
The RIFA may be spread by the movement of soil or plant material and by natural dispersal during mating flights (Tschinkel, 2013). Along with the increasingly massive and interconnected global trade and travel system, the range expansion of the RIFA may be accelerated (Ascunce et al., 2011). Therefore, determining the potential range of the RIFA is necessary prior to making quarantine decisions to curtail or reduce the impact of future introductions. A species distribution model is the only method that can project the potential range of the RIFA. There are two types of model commonly used to simulate the potential RIFA distribution: ecological niche models and process-based models. Sutherst and Maywald (2005)) inferred the response of the RIFA to temperature and moisture from its range in the USA using an ecological niche model (CLIMEX model). However, an ecological niche model based on native range occurrences may underestimate the invasive potential of the RIFA (Fitzpatrick et al., 2007). Korzukhin et al. (2001)) developed a process-based model to simulate the daily colony area and alate production of the RIFA queen using soil temperatures. This model has been used to simulate the regional and global range expansion of the RIFA (Morrison et al., 2004; Morrison et al., 2005; Xiong et al., 2008).
Rapid climate change has the potential to shift the distribution of species around the globe (Chen et al., 2011). Because the global surface temperature change for the end of the 21st century is projected to likely exceed 2°C for RCP (Representative Concentration Pathway) 4.5 and is also likely to exceed 2°C for RCP 6.0 and RCP 8.5 (IPCC, 2013), the area where the reproductive success of the RIFA is expected to be altered in the future. Several studies have reported that the inhabitable area for the RIFA in the USA may increase by more than 20% in a warming climate (Zavaleta and Royval, 2002; Levia and Frost, 2004; Morrison et al., 2005). However, to date no studies have focused on the range expansion of the RIFA in East Asia.
In this study, we simulated the potential range of the RIFA in China under current climate conditions using a well-validated process-based model, and specifically predicted changes in the area of possible infestation in two warming scenarios. Our objective was to provide the basis for adopting prevention and control strategies of RIFA invasions under climate change.

2 Materials and methods

2.1 Data sources

The daily air temperature and precipitation data used in this study were developed by the Data Assimilation and Modeling Center for Tibetan Multi-spheres, Institute of Tibetan Plateau Research, Chinese Academy of Sciences (He and Yang, 2011). This gridded dataset has a spatial resolution of 0.1° × 0.1°, and covers the period of 1981-2012. We used only the data collected since 2004, when the RIFA was first reported in the mainland of China (Zeng et al., 2005).
The future climate data (2090-2100) used were the daily maximum and minimum temperatures simulated by the CCSM 4 model under two Intergovernmental Panel on Climate Change (IPCC) climate scenarios (RCP 4.5 and RCP 8.5), which is available under the Coupled Model Intercomparison Project Phase 5 (CMIP5). The daily mean temperatures were calculated as the mean value of the maximum and minimum temperatures. In RCP 4.5 and RCP 8.5, the global mean temperature was projected to rise by 1.8 and 3.7°C, respectively, by the late 21st century (IPCC, 2013). Since the spatial resolution of future climate data is 0.9375° (latitude) × 1.25° (longitude), we resampled it to 0.1° × 0.1°.
Because the model used in this study was based on soil temperature, we developed a transfer function to change air temperature into surface soil temperature. This was achieved using the daily air temperature and surface soil temperature data in 2010 at 823 meteorological stations in China, which were downloaded from the China Meteorological Service Center ( The formula of the transfer function was taken from Chang et al. (1994)). The calibrated transfer function was as follows:
${{T}_{s}}\text{=}4.23\text{+}0.888{{T}_{a}}-0.329\sin \left( 2\pi \frac{J}{365} \right)-2.67\cos \left( 2\pi \frac{J}{365} \right)$ (1)
where J is the day of the year and Ta and Ts are the air temperature and surface soil temperature, respectively. The statistical characteristics of the transfer function are as follows: R2 = 0.95; RMSE (root-mean-square error) = 2.77 °C; and the number of samples = 298,079.
The range of the RIFA in 2014 was derived from a public report on the website of the Ministry of Agriculture of China. ( t20150604_4634137.htm, in Chinese). This distribution data was provided at the county level rather than for locations with precise geographic coordinates.

2.2 Model description

We adopted a process-based model from Korzukhin et al. (2001)) to simulate the potential inhabitable area of the RIFA. This model assumed that an RIFA queen establishes a nest at a given day of the year (J0), with an initial colony area (S0) in m2. Subsequently, colony area (which is proportional to the number of workers in a colony) began to increase when the soil temperature reached a certain threshold (T1). When the colony area at age t (St) reached reproductive size (Srep), the colony split its growth resources between the worker and alate production. The equations of the model were as follows.
For Tt+1≥T1 and St<Srep:
${{S}_{t+1}}={{S}_{t}}+r({{T}_{t\text{+1}}}){{S}_{t}}\left( 1-\frac{{{S}_{t}}}{{{S}^{\max }}} \right)$ and ${{a}_{t\text{+1}}}=0$ (2)
For Tt+1≥T1 and St>=Srep:
${{S}_{t+1}}={{S}_{t}}+[1-f(DOY)]r({{T}_{t+1}}){{S}_{t}}\left( \text{1}-\frac{{{S}_{t}})}{{{S}^{\max }}} \right)$ and ${{a}_{t\text{+1}}}=qf(DOY)r({{T}_{t+1}}){{S}_{t}}$ (3)
For Tt+1<T1:
${{S}_{t+1}}={{S}_{t}}-\frac{{{S}_{t}}}{L({{T}_{t\text{+1}}})}$ and ${{a}_{t\text{+}1}}=0$ (4)
where St represents the colony area at age t and at represents the number of alates produced by the queen at the date when age = t. Colony area growth is restricted to the maximum colony area (Smax). q is a parameter providing a correspondence between colony size and alate production. There are three empirical curves used in the model: colony growth rate r(T), colony decrease rate 1/L(T), and the share of resources directed to alate production f(DOY). r(T) and L(T) are the functions of soil temperature (T). f(DOY) is the function of the day of the year (DOY). The values of the model parameters and the three curves are shown in the supplementary materials.
The model was run with a one-day step from day J0 of the years 2004 and 2090 using the daily soil temperature data for each 0.1° × 0.1° cell. Surface soil temperatures below 0°C were adjusted to 0°C to account for the movement of the workers to 30 cm depth, where the soil temperature never falls below 0°C even if air temperatures are freezing (Korzukhin et al., 2001). The calculation stopped when t was longer than the maximum longevity of the queen (tmax), or St was smaller than a critical area (Smin). The output variable was the total number of alates (asum) produced by a colony during its lifetime:
${{a}_{sum}}=\sum{{{a}_{t}}}$ (5)

2.3 Statistical analyses

Based on empirical data in the areas where the RIFA is known to survive, a critical threshold of 3900 alates (asum) was used as an estimate of “certain” colony proliferation success (Korzukhin et al., 2001). A critical threshold of 1500 indicated areas of “possible” infestation (Morrison, 2004). asum <1500 indicated an area of “unlikely” infestation. In addition, a threshold of 510 mm for mean annual precipitation was used to identify areas that were too dry to support the RIFA (Korzukhin et al., 2001). The thresholds for defining different possibilities of reproductive success of the RIFA are summarized in Table 1.
Table 1 Different possibilities of the reproductive success of the red imported fire ant (RIFA). asum: the total number of alates produced by a colony during its lifetime. P: mean annual precipitation during 2004-2012.
Types Conditions
Certain infestation asum≥3900 and P≥510 mm
Possible infestation 1500≤asum<3900 and P≥510 mm
Unlikely infestation asum<1500 or P<510 mm
We compared the potential distribution of reproductive success of the RIFA (2004-2012) with the area where the RIFA had invaded by 2014 for each 0.1° × 0.1° cell. To assess the impact of global warming on the range expansion of the RIFA, we simulated the asum during 2090-2100 and determined the different possibilities of infestation in the RCP 4.5 and RCP 8.5 scenarios.

3 Results

3.1 Potential and actual range of the RIFA in China

The certain and possible infestation zones of the RIFA predicted by the model accounted for most of southeastern China, with a total area of 10,180 and 5541 cells (0.1° × 0.1°), respectively (Figure 1a). The northern limit of the certain infestation zone was 32°N. The possible infestation zones of the RIFA extended to 34°N. The area at risk included 20 provinces or regions of China (Table 2). Among them, nine provinces (Hainan, Guangdong, Guangxi, Jiangxi, Fujian, Hong Kong, Taiwan, Shanghai, and Hunan) had the highest risk with more than half of their total area being certain infestation zones (Table 2).
Figure 1 Potential (a) and current (b) range of the red imported fire ant (RIFA) in China. The number of each province/region shown in Figure 1 (b) corresponds to the number in Table 2.
Table 2 Comparisons between the potential and current range of the red imported fire ant (RIFA) for each province or region
No. Name Total area Current area Potential range (%) Comparison (%)
Certain Possible Unlikely Certain Possible Unlikely
23 Hainan 291 93(32.0%) 98.6 1.4 0.0 100.0 0.0 0.0
21 Guangdong 1559 956(61.3%) 92.5 4.9 2.6 94.0 4.2 1.8
18 Guangxi 2103 679(32.3%) 85.6 9.2 5.1 97.1 2.5 0.4
15 Jiangxi 1527 174(11.4%) 79.6 12.6 7.9 92.0 5.7 2.3
20 Fujian 1103 121(11.0%) 62.0 24.1 13.9 80.2 12.4 7.4
22 Hong Kong 26 8(30.8%) 57.7 0.0 42.3 87.5 0.0 12.5
19 Taiwan 322 62(19.3%) 57.1 9.6 33.2 59.7 17.7 22.6
12 Shanghai 59 NaN 55.9 32.2 11.9 NaN NaN NaN
14 Hunan 1929 24(1.2%) 55.7 24.0 20.4 62.5 33.3 4.2
11 Chongqing 770 13(1.7%) 40.4 22.9 36.8 84.6 15.4 0.0
10 Hubei 1755 NaN 39.7 21.9 38.4 NaN NaN NaN
13 Zhejiang 937 NaN 38.5 33.5 28.0 NaN NaN NaN
8 Anhui 1331 NaN 22.8 63.3 14.0 NaN NaN NaN
9 Sichuan 4552 54(1.2%) 20.3 7.8 71.9 24.1 25.9 50.0
16 Yunnan 3422 738(21.6%) 18.6 15.9 65.5 29.0 27.6 43.4
17 Guizhou 1603 NaN 9.8 25.0 65.2 NaN NaN NaN
7 Jiangsu 976 NaN 2.0 61.4 36.6 NaN NaN NaN
4 Shaanxi 2041 NaN 1.5 4.7 93.8 NaN NaN NaN
2 Shanxi 1599 NaN 0.3 1.2 98.5 NaN NaN NaN
6 Henan 1612 NaN 0.0 35.2 64.8 NaN NaN NaN
0 Hebei 1967 NaN 0.0 0.0 100.0 NaN NaN NaN
1 Beijing 175 NaN 0.0 0.0 100.0 NaN NaN NaN
3 Tianjin 121 NaN 0.0 0.0 100.0 NaN NaN NaN
5 Shandong 1546 NaN 0.0 0.0 100.0 NaN NaN NaN

Note: The number of each province (or region) corresponds to the number shown in Figure 1b. The total area of each province and current inhabitable area of the RIFA were measured by the number of cells (0.1 °× 0.1°). The number in the bracket is the percentage of the total area where the RIFA has been reported. The “comparison” columns show the percentages of the current area where the probability of the RIFA being found are certain, possible, or unlikely. NaN indicates that the RIFA had not invaded this province/region by 2014. The province/regions were ordered by the percentage of the total area within the certain infestation zone.

The current range of the RIFA in China was found to be significantly smaller than its potential range (Figure 1b). By 2014, the RIFA had invaded 217 counties in 11 provinces/regions of China. The provinces with the maximum invaded area were Guangdong, Yunnan, Guangxi, Jiangxi, and Fujian (Table 2). In most cases, the current range of the RIFA was found to be within the certain or possible infestation zones simulated by the model. For example, in Hainan, Guangdong, Guangxi, Jiangxi, Fujian, Hong Kong, Hunan, and Chongqing, more than 80% of the current range corresponded to certain or possible infestation zones. However, in other regions (Taiwan, Sichuan, and Yunnan), the actual and potential range did not correspond very well. For example, only 50% of the current distribution area of the RIFA in Sichuan was within certain or possible infestation zones. The reason for this inconsistency was that some areas where the RIFA had not invaded were also included in its current range because the distribution data was at the county scale. This inconsistency was especially pronounced in regions with complex terrain (e.g., Taiwan, Sichuan, and Yunnan). Overall, 75.5% and 11.0% of the current inhabitable area of the RIFA were within the simulated certain and possible infestation zones, respectively.

3.2 Impact of climate warming on the potential range of the RIFA

The area of certain RIFA infestation was projected to increase from 10,180 cells at present to 14,335 cells in RCP 4.5 and 22,327 cells for RCP 8.5 by the late 21st century (Figure 2). The rate of increase in the inhabitable area was 40.8% and 119.3% in the RCP 4.5 and RCP 8.5 scenarios, respectively. The certain infestation area in eastern China would on average extend by 9.1 and 63.0 cells toward higher latitudes from the 2000s to the 2090s in the RCP 4.5 and RCP 8.5 scenarios, respectively (Figure 2). Because each cell was 11.13 km in its north-south dimension, the northward shift of the inhabitable area for the RIFA would be 101.3±85.7 (mean±SD) and 701.2±156.9 km in the RCP 4.5 and RCP 8.5 scenarios, respectively. In RCP 8.5, provinces that would see relatively large increases in the certain infestation zone of the RIFA included Henan, Guizhou, Shandong, Yunnan, and Anhui, with an additional >1,000 cells becoming certain infestation zones compared to the current climate condition.
Figure 2 Potential range of the red imported fire ant (RIFA) in the warming scenarios. The northern boundary of the potential and certain infestation zones of the RIFA in the current climate condition (2004-2013) are shown: (a) RCP 4.5; (b) RCP 8.5.

4 Discussion

4.1 Factors limiting the distribution of the RIFA in China

Soil temperature and moisture are the two most important climate factors affecting the distribution of the RIFA (Ward, 2009). According to the basis of the model used in this study, the total number of alates produced by a queen is a function of soil temperature. An RIFA queen that produces an insufficient number of alates is indicative of a temperature limitation on the RIFA distribution. In an area with less than 510 mm annual precipitation, moisture restricts the RIFA distribution. The factors limiting the RIFA distribution in different regions of China are shown in Figure 3. Except for in the certain infestation zones, the temperature was the factor that limited RIFA proliferation. Precipitation only restricted the RIFA proliferation in northwestern China. Therefore, the range expansion of the RIFA in China is more sensitive to changes in temperature rather than precipitation.
Figure 3 The factors limiting RIFA distribution in China. T: temperature; P: precipitation.

4.2 The impact of climate change

The RCPs represent atmospheric concentrations of greenhouse gases (GHGs) in different scenarios of future anthropogenic GHG emissions. RCP 4.5 assumes that global annual GHG emissions peak around 2040, and then decline. In RCP 8.5, emissions continue to rise throughout the 21st century (Meinshausen et al., 2011). This study found that the potential range of the RIFA will noticeably increase in these two scenarios, especially the high-emission scenario (RCP 8.5). The area suitable for RIFA colonization in China increased by 40.8% and 119.3% in RCP 4.5 and RCP 8.5, respectively. This result was consistent with earlier findings in the USA. In Oklahoma, the area suitable for invasion by the RIFA increased by at least 26% with a doubling of atmospheric CO2, based on data from three general circulation models (Levia and Frost, 2004). Morrison et al. (2005)) indicated that the inhabitable area of the RIFA in 2100 is predicted to be >21% greater than it currently using climate data from the Vegetation-Ecosystem Modeling and Analysis Project based on IS92a scenarios. However, these estimates may not be directly comparable with each other because different climate change scenarios were used.
Table 3 The difference in the number of cells within the certain infestation zone of the red imported fire ant (RIFA) between the 2000s and the 2090s in RCP 4.5 and RCP 8.5.
Number Name RCP 4.5 RCP 8.5
6 Henan 9 1482
17 Guizhou 594 1388
5 Shandong 0 1309
16 Yunnan 259 1290
8 Anhui 455 1028
7 Jiangsu 316 956
14 Hunan 753 855
10 Hubei 101 846
13 Zhejiang 565 565
20 Fujian 417 417
0 Hebei 0 400
11 Chongqing 33 373
9 Sichuan ‒139 336
15 Jiangxi 312 312
18 Guangxi 248 302
19 Taiwan 133 133
21 Guangdong 112 112
12 Shanghai 19 19
4 Shaanxi ‒31 11
2 Shanxi ‒5 9
23 Hainan 4 4
1 Beijing 0 0
3 Tianjin 0 0
22 Hong Kong 0 0
Note: The number of each province (or region) corresponds to the number shown in Figure 1b. The province/regions are ordered by the difference in RCP 8.5.

4.3 Limitations of the model

The model used in this study only considered the impact of soil temperature on the potential invasion by the RIFA. Other factors that may influence the spread of the RIFA include access to food resources, competition with other insects (Tschinkel and King, 2017), physical attributes of the habitat, predation, and human management of the landscape (Roura-Pascual and Suarez, 2008). Therefore, the potential distributions identified in this study should be regarded as approximations that represent possible changes in the direction and magnitude of invasion.

5 Conclusions

In conclusion, this study simulated the potential range of the RIFA in China using a process-based model. The model predicted that most of southern China may be suitable for RIFA invasion. A total of 86.5% of the area where RIFA has invaded was within the possible or certain infestation zones simulated by the model. In the RCP 4.5 and RCP 8.5 scenarios,
the area suitable for colonization in China will move northward by 101.3 and 701.2 km on average, respectively. These results provide decision makers with probable infestation zones so that they can adopt appropriate quarantine measures in areas with a high risk of invasion.


Table S1 Standard values of model parameters derived from Korzukhin et al. (2001))
Model parameters Values
Max territory area, Smax 100 m2
Territory area at which worker mortality causes colony death, Smin 0.02 m2
Minimum area for colony production Srep 10 m2
Initial territory area, S0 0.01 m2
Queen longevity, tmax 3000 days
Colony proliferation parameter, q 89
The day of the year when colony founding, J0 165
Temperature when colony growth begins, T1 21°C
Figure S1 Three empirical curves used in the model of Korzukhin et al. (2001). (a) Colony growth rate in response to soil temperature (T). (b) Worker longevity L(T). 1/L(T) represents the colony decrease rate in response to T. (c) The share of resources directed to alate production f(DOY). DOY: day of the year.

The authors have declared that no competing interests exist.

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Chen I, Hill J K, Ohlemüller R, et al., 2011. Rapid range shifts of species associated with high levels of climate warming.Science, 333(6045): 1024-1026.Abstract The distributions of many terrestrial organisms are currently shifting in latitude or elevation in response to changing climate. Using a meta-analysis, we estimated that the distributions of species have recently shifted to higher elevations at a median rate of 11.0 meters per decade, and to higher latitudes at a median rate of 16.9 kilometers per decade. These rates are approximately two and three times faster than previously reported. The distances moved by species are greatest in studies showing the highest levels of warming, with average latitudinal shifts being generally sufficient to track temperature changes. However, individual species vary greatly in their rates of change, suggesting that the range shift of each species depends on multiple internal species traits and external drivers of change. Rapid average shifts derive from a wide diversity of responses by individual species.


Chen J, Shen C H, Lee H J, 2006. Monogynous and polygynous red imported fire ants, Solenopsis invicta buren (Hymenoptera: Formicidae), in Taiwan Environmental Entomology, 35(1): 167-172.ABSTRACT The social forms of the red imported fire ant, initially discovered in Taoyuan County in 2003, were determined based on Gp-9 allele identification. Both polygynous and monogynous colonies were found. It was also found that, in almost all of townships surveyed, there was tendency to have more polygynous nests than monogynous nests. The monogynous nests were indeed authentic monogynous nests without contamination of the cryptic b-prime allele from South America. Sequence comparison revealed that polygynous colonies in Taiwan contained either the Gp-9B1 or Gp-9 B3 variant (Sinv.B1 and Sinv.B3 in GenBank) of the B allele, whereas some of the monogynous colonies contained a Gp-9B2-like variant of the B allele (Sinv.B2 in GenBank). Gp-9 B1 also was found in some monogynous colonies. The scenario of a single introduction by a founding polygynous colony with all of the monogynous nests being descendents of this polygynous nest was also ruled unlikely because of the presence of the monogyne-specific B2 allele. These findings favor multiple origins of the red imported fire ant in Taiwan.


Cook J L, 2003. Conservation of biodiversity in an area impacted by the red imported fire ant,Solenopsis invicta(Hymenoptera: Formicidae). Biodiversity and Conservation, 12(2): 187-195.

DeShazo R D, Williams D F, Moak E S, 1999. Fire ant attacks on residents in health care facilities: A report of two cases.Annals of Internal Medicine, 131(6): 424-429.Case reports of 2 Solenopsis invicta attacks on patients in health care facilities in Mississippi, USA, in 1997-98 are presented. The patients were a 67-year-old woman and a 60-year-old man. With the 2 incidents reported here, the total number of reported indoor fire ant attacks on humans since 1989 is 10. Six of the persons attacked, including the 2 nursing home residents described here (who d...


Fitzpatrick M C, Weltzin J F, Sanders N J, et al., 2007. The biogeography of prediction error: Why does the introduced range of the fire ant over-predict its native range?Global Ecology and Biogeography, 16(1): 24-33.Aim The use of species distribution models (SDMs) to predict biological invasions is a rapidly developing area of ecology. However, most studies investigating SDMs typically ignore prediction errors and instead focus on regions where native distributions correctly predict invaded ranges. We investigated the ecological significance of prediction errors using reciprocal comparisons between the predicted invaded and native range of the red imported fire ant ( Solenopsis invicta ) (hereafter called the fire ant). We questioned whether fire ants occupy similar environments in their native and introduced range, how the environments that fire ants occupy in their introduced range changed through time relative to their native range, and where fire ant propagules are likely to have originated. Location We developed models for South America and the conterminous United States (US) of America. Methods We developed models using the Genetic Algorithm for Rule-set Prediction (GARP) and 12 environmental layers. Occurrence data from the native range in South America were used to predict the introduced range in the US and vice versa. Further, time-series data recording the invasion of fire ants in the US were used to predict the native range. Results Native range occurrences under-predicted the invasive potential of fire ants, whereas occurrence data from the US over-predicted the southern boundary of the native range. Secondly, introduced fire ants initially established in environments similar to those in their native range, but subsequently invaded harsher environments. Time-series data suggest that fire ant propagules originated near the southern limit of their native range. Conclusions Our findings suggest that fire ants from a peripheral native population established in an environment similar to their native environment, and then ultimately expanded into environments in which they are not found in their native range. We argue that reciprocal comparisons between predicted native and invaded ranges will facilitate a better understanding of the biogeography of invasive and native species and of the role of SDMs in predicting future distributions.


Gutrich J J, VanGelder E, Loope L, 2007. Potential economic impact of introduction and spread of the red imported fire ant, Solenopsis invicta, in Hawaii. Environmental Science & Policy, 10(7-8): 685-696.Globally, many invasive alien species have caused extensive ecological and economic damage from either accidental or intentional introduction. The red imported fire ant, Solenopsis invicta, has created billions of dollars in costs annually, spreading as an invasive species across the southern United States. In 1998, the red imported fire ant spread into California creating a highly probable future introduction via shipped products to Hawaii. This paper presents the estimation of potential economic impacts of the red imported fire ant (RIFA) to the state of Hawaii. Evaluation of impacts focuses on the economic sectors of (1) households, (2) agriculture (cattle and crop production), (3) infrastructure (cemeteries, churches, cities, electrical, telephone, and cable services, highways, hospitals and schools), (4) recreation, tourism and business (hotels/resort areas, golf courses, commercial businesses and tourists), and (5) government expenditures (with minimal intervention). The full annual economic costs of the red imported fire ant to Hawaii are estimated (in US$ 2006) to be $211 million/year, comprised of $77 million in damages and expenditures and $134 million in foregone outdoor opportunities to households and tourists. The present value of the projected costs of RIFA over a 20-year period after introduction total $2.5 billion. RIFA invasions across the globe indicate that economic cost-effective action in Hawaii entails implementation of prevention, early detection and rapid response treatment programs for RIFA.


He J, Yang K, 2011. China meteorological forcing dataset.Cold and Arid Regions Science Data Center at Lanzhou, doi: 10.3972/westdc.002.2014.db.

Holway D A, Lach L, Suarez A V, et al., 2002. The causes and consequences of ant invasions.Annual Review of Ecology and Systematics, 33: 181-233.Invasions by non-native ants are an ecologically destructive phenomenon affecting both continental and island ecosystems throughout the world. Invasive ants often become highly abundant in their introduced range and can outnumber native ants. These numerical disparities underlie the competitive asymmetry between invasive ants and native ants and result from a complex interplay of behavioral, ecological, and genetic factors. Reductions in the diversity and abundance of native ants resulting from ant invasions give rise to a variety of direct and indirect effects on non-ant taxa. Invasive ants compete with and prey upon a diversity of other organisms, including some vertebrates, and may enter into or disrupt mutualistic interactions with numerous plants and other insects. Experimental studies and research focused on the native range ecology of invasive ants will be especially valuable contributions to this field of study.


IPCC, 2013. Summary for policymakers. Climate Change 2013: The Physical Science Basis. In: Stocker T F,Qin D, Plattner G K, et al. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge: Cambridge University Press, 3-29.

Kenis M, Auger-Rozenberg M, Roques Aet al., 2009. Ecological effects of invasive alien insects.Biological Invasions, 11(1): 21-45.A literature survey identified 403 primary research publications that investigated the ecological effects of invasive alien insects and/or the mechanisms underlying these effects. The majority of these studies were published in the last 8 years and nearly two-thirds were carried out in North America. These publications concerned 72 invasive insect species, of which two ant species, Solenopsis invicta and Linepithema humile , accounted for 18% and 14% of the studies, respectively. Most publications investigated effects on native biodiversity at population or community level. Genetic effects and, to a lesser extent, effects on ecosystem services and processes were rarely explored. We review the effects caused by different insect invaders according to: their ecosystem roles, i.e. herbivores, predators, parasites, parasitoids and pollinators; the level of biological organisation at which they occur; and the direct and indirect mechanisms underlying these effects. The best documented effects occur in invasive ants, Eurasian forest herbivores invasive in North America, and honeybees. Impacts may occur through simple trophic interactions such as herbivory, predation or parasitism. Alien species may also affect native species and communities through more complex mechanisms such as competition for resources, disease transmission, apparent competition, or pollination disruption, among others. Finally, some invasive insects, particularly forest herbivores and ants, are known to affect ecosystem processes through cascading effects. We identify biases and gaps in our knowledge of ecological effects of invasive insects and suggest further opportunities for research.


Korzukhin M D, Porter S D, Thompson L C, et al., 2001. Modeling temperature-dependent range limits for the fire ant Solenopsis invicta(Hymenoptera: Formicidae) in the United States. Environmental Entomology, 30(4): 645-655.We predict the future range of the fire ant Buren within the United States based on climate and its current extreme distributions. To reach that goal, a dynamic model of colony growth with two time steps per day was formulated that operates by colony area, , and alate production, Colony growth rate depended on daily maximum and minimum soil temperatures. Temperature records at 4,537 meteorological stations within the current (near 1.5 million km) and potential range of were obtained from NOAA National Climatic Data Center. At each station, a colony was allowed to grow and lifetime female alate production was calculated. Estimated alate production was then examined at current extremes of the fire ant distribution at selected locations in Arkansas, Tennessee, and Oklahoma. Estimates from these locations were used to define four zones of colony proliferation success: certain, possible, undemonstrated, and improbable. An annual precipitation limit (510 mm) was selected to indicate regions where arid conditions may prohibit growth in areas without supplemental water sources. Results of the model predict that will likely move 80 150 km north in Oklahoma and Arkansas. It will also likely continue expanding into portions of Virginia, Maryland, and Delaware in the east and New Mexico, Arizona, California, Oregon, Nevada, and maybe even Washington and Utah in the west.


Levia D F, Frost E E, 2004. Assessment of climatic suitability for the expansion of Solenopsis invicta Buren in Oklahoma using three general circulation models. Theoretical and Applied Climatology, 79(1): 23-30.This study assessed the climatic suitability for the expansion of Solenopsis invicta Buren (red imported fire ant) in Oklahoma under the present climate and with a doubling of atmospheric CO 2 using three general circulation models (GCMs) (GFDL R30, OSU, UKMO). Oklahoma was chosen as the geographical focus because it has a dense network of meteorological stations and lies on the edge of the current biogeographic range of S. invicta . Meteorological data were spatially referenced with model data in GIS to produce a series of images of selected suitability indicators: (1) mean annual precipitation >51065mm; (2) less than seven consecutive days with mean air temperature 9.465C. These indicator images were combined to produce suitability maps for the potential range of S. invicta . Under current climatic conditions, roughly three-quarters of Oklahoma is suitable for potential invasion by S. invicta . The GFDL R30, OSU, and UKMO show that the area suitable for colonization increases by approximately 26, 26, and 36%, respectively. In terms of actual land area, the increase with a warmer, wetter climate ranges from 35,30065km 2 to 47,60065km 2 . The destructiveness of S. invicta on human livelihood necessitates a better understanding of the future expansion of the species for an uncertain future climate.


Lu Y, Wu B, Xu Y, et al., 2012. Effects of red imported fire ants (Solenopsis invicta) on the species structure of ant communities in South China. Sociobiology, 59(1): 275-285.ABSTRACT We evaluated the effects of invasive red imported fire ants (RIFAs), Solenopsis invicta Buren, on native ant communities at three habitats in South China. By using paired control and treatment plots, the change in diversity and community structure of native ants due to the invasion of red imported fire ants could be observed. Ant species richness was reduced by 46 and 33% at RIFA-infested lawn and pasture habitats, respectively; however, the ant species richness in the lichee orchard was not affected by red imported fire ants. Our results indicated that red imported fire ants became one of several dominant species or the only dominant species in all three habitats in South China.


Meinshausen M, Smith S J, Calvin Ket al., 2011. The RCP greenhouse gas concentrations and their extensions from 1765 to 2300.Climatic Change, 109(1): 213.We present the greenhouse gas concentrations for the Representative Concentration Pathways (RCPs) and their extensions beyond 2100, the Extended Concentration Pathways (ECPs). These projections include all major anthropogenic greenhouse gases and are a result of a multi-year effort to produce new scenarios for climate change research. We combine a suite of atmospheric concentration observations and emissions estimates for greenhouse gases (GHGs) through the historical period (1750–2005) with harmonized emissions projected by four different Integrated Assessment Models for 2005–2100. As concentrations are somewhat dependent on the future climate itself (due to climate feedbacks in the carbon and other gas cycles), we emulate median response characteristics of models assessed in the IPCC Fourth Assessment Report using the reduced-complexity carbon cycle climate model MAGICC6. Projected ‘best-estimate’ global-mean surface temperature increases (using inter alia a climate sensitivity of 3°C) range from 1.5°C by 2100 for the lowest of the four RCPs, called both RCP3-PD and RCP2.6, to 4.5°C for the highest one, RCP8.5, relative to pre-industrial levels. Beyond 2100, we present the ECPs that are simple extensions of the RCPs, based on the assumption of either smoothly stabilizing concentrations or constant emissions: For example, the lower RCP2.6 pathway represents a strong mitigation scenario and is extended by assuming constant emissions after 2100 (including net negative CO 2 emissions), leading to CO 2 concentrations returning to 36002ppm by 2300. We also present the GHG concentrations for one supplementary extension, which illustrates the stringent emissions implications of attempting to go back to ECP4.5 concentration levels by 2250 after emissions during the 21 st century followed the higher RCP6 scenario. Corresponding radiative forcing values are presented for the RCP and ECPs.


Mikheyev A S, Mueller U G, 2006. Invasive species: Customs intercepts reveal what makes a good ant stowaway.Current Biology, 16(4): R129-R131.A recent analysis of decades of US customs intercepts has revealed which ants had an opportunity to become established in the United States, providing insights into the requisite traits that enable an ant species to become a successful invader.


Morrison L W, Porter S D, Daniels Eet al., 2004. Potential global range expansion of the invasive fire ant,solenopsis invicta. Biological Invasions, 6(2): 183-191.

Morrison L W, Korzukhin M D, Porter S D, 2005. Predicted range expansion of the invasive fire ant,Solenopsis invicta, in the eastern United States based on the VEMAP global warming scenario. Diversity and Distributions, 11(3):;P>The red imported fire ant, Solenopsis invicta Buren, is an invasive pest from South America that currently occupies much of the south-eastern USA. Global warming is likely to allow range expansion of many invasive species, including S. invicta . We used a dynamic, ecophysiological model of fire ant colony growth coupled with models simulating climate change to predict the potential range expansion of S. invicta in the eastern USA over the next century. The climate change scenario predicted by the Vegetation–Ecosystem Modelling and Analysis Project (VEMAP) was used in our analyses. Our predictions indicate that the habitable area for S. invicta may increase by c. 5% over the next 40–50 years (a northward expansion of 33 ± 35 km). As the pace of global warming is expected to quicken in the latter half of the century, however, the habitable area for S. invicta in 2100 is predicted to be > 21% greater than it currently is (a northward expansion of 133 ± 68 km). Because the black imported fire ant, S. richteri Forel, occupies higher latitudes than S. invicta , the overall area of the eastern USA infested with invasive Solenopsis species could be greater than that estimated here.</P>


Roura-Pascual N, Suarez A V, 2008. The utility of species distribution models to predict the spread of invasive ants (Hymenoptera: Formicidae) and to anticipate changes in their ranges in the face of global climate change.Myrmecological News, 11: 67-77.

Simberloff D, Martin J, Genovesi P, et al., 2013. Impacts of biological invasions: What’s what and the way forward.Trends in Ecology & Evolution, 28(1): 58-66.Study of the impacts of biological invasions, a pervasive component of global change, has generated remarkable understanding of the mechanisms and consequences of the spread of introduced populations. The growing field of invasion science, poised at a crossroads where ecology, social sciences, resource management, and public perception meet, is increasingly exposed to critical scrutiny from several perspectives. Although the rate of biological invasions, elucidation of their consequences, and knowledge about mitigation are growing rapidly, the very need for invasion science is disputed. Here, we highlight recent progress in understanding invasion impacts and management, and discuss the challenges that the discipline faces in its science and interactions with society.


Sutherst R W, Maywald G, 2005. A climate model of the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae): Implications for invasion of new regions, particularly Oceania Environmental Entomology, 34(2): 317-335.

Teal S, Segarra E, Barr C, et al., 1999. The cost of red imported fire ant infestation: The case of the Texas cattle industry.Texas Journal of Agriculture and Natural Resources, 12: 86-95.react-text: 221 Includes bibliographical references (leaves 105-109). Vita. Thesis (Ph. D.)--Texas A & M University, 1997. Microfilm. s /react-text react-text: 222 /react-text

Tschinkel W R, 2013. The fire ants. Cambridge: Belknap Press of Harvard University Press, 1-752.

Tschinkel W R, King J R, 2017. Ant community and habitat limit colony establishment by the fire ant, Solenopsis invicta. Functional Ecology, 31(4): 955-964.Abstract Hypotheses of community assembly include limitation through habitat physical attributes, as well as competition among species. Such hypotheses must be resolved through experimental tests. Previous experiments have shown: (1) that fire ants of the monogyne social form occur mostly in highly disturbed habitat where they do not compete with mature colonies of co-occurring ants. (2) In native pine forests of northern Florida, habitat disturbance favors fire ants while simultaneously reducing native ants. (3) Fire ants thrive in these disturbances but do not persist as these become less disturbed over time. Finally, (4) newly-mated, dispersing/colony-founding fire ant queens settle preferentially in such disturbed sites. We now show that by choosing disturbed sites, newly-mated, monogyne fire ant queens greatly increase their chances of successful colony establishment. Experimental plots were created in the native ground cover of a north Florida pine forest with all combinations of tilling, shading or reduction of the native ant community. Newly-mated fire ant queens, incipient colonies and small colonies were planted in these plots. Only 5 of 980 (0.5%) newly-mated queen nests survived after 120 days, and only 5 of 400 incipient colonies (1.3%) survived after 30 days. All survivors were in plots with tilling and/or native ant reduction. Extrapolation indicated that 0.04% of newly mated queens and 0.1% of incipient colonies were likely to have survived at one year. In contrast, planting small colonies resulted in much higher rates of survival in plots with native ant reduction, fire ants increased on baits throughout the year but decreased in unreduced control plots. Fifteen months after planting 108 colonies, 21 mounds (19%) were found in the ant-reduced plots, but less than 2% of 108 colonies survived in the control plots. Taken together, these results show that by landing in disturbed habitat with its reduced native ant population, newly mated fire ants queens increase their chances of successful colony establishment. In contrast to much of the previous literature our results suggest that ant community assembly proceeds primarily by queen habitat choice and secondarily by filtering and competition. This article is protected by copyright. All rights reserved.


Vinson S B, 1997. Insect life: Invasion of the red imported fire ant (Hymenoptera: Formicidae).American Entomologist, 43(1): 23-39.ABSTRACT The red imported fire ant, Solenopsis invicta Buren, hereafter referred to as the imported fire ant, has received much press coverage since its introduction into the United States approximately 75 years ago. This is not because Qf its fascinating biology, which I will cover, but to the fear and frustration of citizens who have come in contact with this insect. The news media have recognized the public's frustration and, while providing important information, have tended to exaggerate and fan the fires of frustration and fear. Following the United States Department of Agriculture's recognition that imported fire ants were a problem in 1950, many newspaper headlines have appeared that have given the impression that not only are these ants dangerous, they are marching across the South and will soon invade your area. Some of the more sensational ones include, “Possibly lethal hordes of fire ants plague sadden Texas areas” (Washington Post, 30 October 1981); “But insects `are winning': officials fighting to check fire ants march through Texas” (Los Angeles Times, 5 December 1981); “War on fire ants still suffers stinging losses” (Chicago Tribune, 13 June 1982); and “Woman puts up tough fight before dying from fire ant stings” (Houston Chronicle, 23 November 1990). Further, pictures like the cover of The Magazine of San Antonio (May 1980) taken from a poster advertising the movie Empire of the Ants (American International Pictures 1977) or the paperback book, The Fire Ants (Wernick 1976) suggest these ants are at least the size of a squirrel, not unlike the ants featured in the movie Them (Warner Brothers 1954). The ants are the subject of many magazine articles (Michel 1984, Glass-Godwin 1992, Killion and Vinson 1995). Imported fire ants also have received magazine cover status in such publications as Smithsonian (July 1990) and Texas Monthly Magazine (August 1988). They even have entered our popular culture as indicated by their inclusion in several cartoons such as Bloom County (Breathed 1981) or Mother Goose and Grimm (Peter 1989). However, the cover of Texas Monthly Magazine probably stated best what most people in the infested region consider this creature, (i.e., “Public Enemy Number One”). But, is this designation deserved? To examine this question I first will cover the fire ant's biology and then some of the problems.

Ward D, 2009. The potential distribution of the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), in New Zealand New Zealand Entomologist, 32(1): 67-75.

Wickings K, Ruberson J R, 2016. The red imported fire ant, Solenopsis invicta, modifies predation at the soil surface and in cotton foliage. Annals of Applied Biology, 169(3): 319-328.

Wylie R, Jennings C, McNaught M K, et al., 2016. Eradication of two incursions of the red imported fire ant in Queensland, Australia.Ecological Management & Restoration, 17(1): 22-32.Of the five known incursions of the highly invasive Red Imported Fire Ant in Australia, two are regarded to have been eradicated. As treatment efforts continue, and the programme evolves and new tools become available, eradication is still considered to be feasible for the remaining Red Imported Fire Ant populations with long-term commitment and support.


Xiong Y, Chen J, Gu Z, et al., 2008. The potential suitability of Jiangsu Province, east China for the invasive red imported fire ant, Solenopsis invicta. Biological Invasions, 10(4): 475-481.The red imported fire ant Solenopsis invicta Buren (RIFA), an invasive pest that has diverse detrimental impacts on the communities it invades, was recently discovered in China and has the potential to colonize numerous other regions. Using the model of Korzukhin etal. as modified by Morrison etal. and the biological and ecological characteristics of RIFA, we show that Jiangsu Province is a potentially suitable establishment area of RIFA. An isotherm map made by ArcMap, a Geographic Information System, indicated that several regions of Jiangsu Province (Changzhou, Liyang, Wuxian Dongshan, Nanjing and Lvsi) are at higher risk of S . invicta infestation, especially from late July and early August. Quarantine officials should be vigilant for any accidental introductions of this pest in the susceptible regions and time.


Zavaleta E S, Royval J L, 2002. Climate change and the susceptibility of U.S. Ecosystems to biological invasions:Two cases of expected range expansion. Wildlife Responses to Climate Change: North American Case Studies, Schneider S H, Root T L, Washington, DC: Island Press, 277-341.

Zeng L, Lu Y, He X, et al., 2005. Identification of red imported fire ant Solenopsis invicta to invade mainland China and infestation in Wuchuan, Guangdong. Chinese Bulletin of Entomology, 42(2): 144-148. (in Chinese)Red imported fire ant, Solenopsis invicta Buren, origin from Latin America including Brazil, Paraguay and Argentina, was one of most dangerous and devastating pests in the world. It spreads continuously and invades many countries and regions now. It was found to infest in Wuchaun, Guangdong through identification of specimen collected. The population density and influence on agriculture, health was presented in this paper. 453 bp of Cytochrome b (Cyt b) gene from two populations (Florida, American and Wuchuan, Guangdong) of Solenopsis invicta and four populations of S. geminata from Guangdong were sequenced. These are 61 variable sits between these two species. No variable sit was found between the two populations in Solenopsis invicta. The result of RFLP showed that there was one restrictive site detected by restriction endonucleases MspI in the amplified segments of S. geminata but none of S. invicta's. BamHI digested amplified segments of S. invicta but not of S. geminata. Digestion of the 453 bp fragment by enzymes BamHI and MspI generates a 200 bp and a 250 bp fragment which could be used as a powerful tool for identification of these two species.