Imported Red Fire Ant

( Solenopsis invicta )

 

Mario Chavez & Veronica Treviso

 

 

Bridges for the Future

 

UTEP/ EPCC

 

 

 

 

Abstract

The objective of this experiment was to determine if Solenopsis invicta has spread into mesic and xeric environments in urban and desert communities of West Texas. We sampled 200 sites within the urban areas of El Paso and 200 sites on the desert areas surrounding El Paso. Both areas of El Paso were sampled using surface and subterranean baits. We determined that S. invicta was found in two mesic environments and one xeric environment within the urban community of El Paso. The findings of S. invicta in mesic environments was expected, however, S. invicta in a xeric environment was not expected. Possibly S. invicta was caught during a migratory period or even while forging for food.

The red imported fire ant, Solenopsis invicta, has greatly spread throughout the southern United States. The homeland of S. invicta is in South America in the Pantanal area of Mato Grosso, Brazil that is a large swampy grassland with large trees which is flooded naturally every year (Wojick, 1983). It has spread through the southern United States at a great rate possibly because there are many areas that are similar to their natural environment. S. invicta was first introduced into the United States around the area of Mobile, Alabama between 1933 and 1945 (Buren, Allen, Whitcomb, Lennartz and Williams, 1974). It was determined in 1980 that S. invicta had invaded nine states from the Carolinas to Texas (Lofgren, Banks and Glancey, 1975). It is now known that the nine states, most of Texas and now even California is infested with this red imported fire ant, S. invicta.

There are three problems caused by the red imported fire ant, S. invicta. The first problem is the contact with people. When people are stung it causes great discomfort, infection and even life threatening situations to those that suffer from allergic reactions caused by insect bites (Lofgren and Vander Meer, 1986). The second problem is in urban areas that can easily be described as schools, parks and recreational areas. The red imported fire ant makes its mounds in large open spaces that can be an urban area where people are more likely to be attacked (University of Arkansas, 1997). The third problem with S. invicta is with agriculture and wildlife. S. invicta destroys vegetation and kills small wildlife when they are in search of food( University of Arkansas, 1997).

The objective of this study is to determine if S. invicta has spread from East Texas to the West Texas city of El Paso and its surrounding areas. Our experimental hypothesis states that S. invicta has spread into mesic environments in urban and desert communities in the El Paso area or into xeric environments in urban and desert communities in the El Paso area. Our null hypothesis states that the appearance of S. invicta in mesic or xeric environments of urban and desert communities in the El Paso area will not be found here in West Texas.

Methods and Materials

The study site for this experiment is in El Paso which is the farthest city in West Texas and is part of the semi arid northern Chihuahuan Desert. The first part of the survey took place in the urban area of El Paso. This survey is being conducted throughout the state of Texas as well as El Paso. The 200 sites sampled were determined by generating 200 random numbers on an Excel program and using them on a coordinated grid system map of the city to pin point the approximate location to be sampled. These sites included residential areas, schools, apartment complexes, parks, vacant lots and golf courses. The two types of baits that were used consisted of surface and subterranean traps. There were five surface and five subterranean baits in the front yard numbered F1 through F5 and five surface and five subterranean in the back yard numbered B6 through B10 (Fig. 1). The surface baits consisted of one ounce Dixie brand cups with lids and a piece of Tuna Flavored Tender Vittle Cat Food. The subterranean baits consisted of 2 mL. Corning cryogenic vials with ten holes drilled and a live meal worm inside. The subterranean baits were set at least ten inches under the ground. The surface baits were used to collect some surface ants that were in search of food including S. invicta and the subterranean baits were used to collect any ants that may be predacious towards this red imported fire ant.

The second part of our survey was conducted in the desert area surrounding El Paso. The 200 sites were selected by doing 50 sites at each north, south, east and west locations of El Paso. These sites were desert roads and the random site was selected by using a dice with the numbers one through four which we rolled and then traveled the tenths of a mile indicated to the next site. The same ten surface and subterranean baits were used with the exception of left and right side of the desert road. The left side were numbered L1 through L5 and the right side were numbered R6 through R10 (Fig. 2). The research for both areas was done early morning or very late in the evening. It was done in this manner because previous research showed that S. invicta was more actively in search of food when the weather conditions were under 90 degrees Fahrenheit.

List of Materials 

* 1 oz. Dixie Cups with Lids

* Tuna Flavored Tender Vittles

- one piece per Dixie cup

* 2 mL. Cryogenic Vials

- live meal worms

* Reclosable Plastic Bags

* Global Positioning System (GPS)

* Temperature Probe

* Hammer and Nail

* Scintillation Vials (filled with 70% ethanol)

* Logging Sheet

Results and Discussion

The red imported fire ant, S. invicta, was found in two mesic environments in the El Paso area. The first site that S. invicta was found was in the front lawn of the library at the University of Texas at El Paso (UTEP). The second site where the red imported fire ant was located was in the bowl area of the Chamizal National Memorial Park where the weekly concerts of Music Under the Stars are held. We believe that S. invicta was found in this area because it is similar to their natural habitat. The two sites that S. invicta were found are similar to their natural habitat. Their natural habitat consists of warm and moist climate and since many people in El Paso water frequently it creates a perfect environment for them to survive. To see a distribution of ants found in the urban area see Table 1.

S. invicta was found in only one xeric environment in the El Paso area. The red imported fire ant was found on Sunset road which was a residential area in the west side of El Paso that had desert landscaping. The finding of S. invicta in a xeric environment was unpredicted because previous research showed that a hot and dry environment was not a place for their survival. Although it is unknown why S. invicta was found in one xeric environment there was no other presence identified in any of the 200 desert sites sampled. To see a distribution of ants found in the desert area see Table 2. There are several possible reasons why S. invicta may have found in a desert community as they may have been forging for food. Another possibility could be that there was grass in that area before or that they were simply migrating to a different area.

Conclusions

My experimental hypothesis states that S. invicta has spread into mesic environments in urban and desert communities of El Paso. I accept that S. invicta has spread into mesic environments in urban communities because it was found at UTEP and the Chamizal National Memorial Park. I reject that S. invicta will spread to mesic environments in desert communities because they were not found in any of these areas.

My experimental hypothesis states that S. invicta has spread into xeric environments in urban and desert communities of El Paso. I accept that S. invicta has spread into xeric environments in urban communities because it was found at a residence with desert landscaping in the west side of El Paso. I reject that S. invicta will spread to xeric environments in desert communities because there was no presence found in the desert of El Paso.

We believe that there should be further research done for many reasons. There should be more sampling done around the west El Paso residence in order to possibly explain why S. invicta was found in a xeric environment. I suggest that neighboring homes and other areas around that house should be sampled. The sampling of other homes with mesic and xeric environments within the urban area should also be further researched in order to examine other possible locations of S. invicta.

Acknowledgments

We would like to thank Dr. William P. Mackay, Dr. Jerry Johnson, Hilda Taylor, Heather Jimenez, Nick Lannutti, Matthew McMillan and all of the students in the Desert Ecology Laboratory at the University of Texas at El Paso and in the Bridges for the Future Program for all of their help and support.

BIBLIOGRAPHY 

1.  Buren, William F., George E. Allen, Willard H. Whitcomb, Frances E. Lennartz, and Roger N. Williams. 1974. Zoogeography of the Imported Fire Ants. Journal of the New York Entomological Society 2:113-123.

2.  Lofgren, C. S., W. A. Banks, and B. M. Glancey. 1975. Biology and Control of Imported Fire Ants. Annual Review of Entomology 20:1-18.

3.  Lofgren, C.S., and Robert K. Vander Meer. 1986. Fire Ants and Leaf-Cutting Ants: Biology and Management. 48-55.

4.  University of Arkansas. 1997. Imported Fire Ant Bytes. CD ROM.

5.  Wojcik, Daniel P. 1983. Comparison of the Ecology of Red Imported Fire Ants in North and South America. The Florida Entomologist 1:101-111.

 

LIST OF FIGURES

 

Figure 1 - Experimental design for the urban sector of El Paso, TX.

Figure 2 - Experimental design for the surrounding desert community of El Paso, TX.

Figure 1

F3 F1 B7 B9

 

F5                    Building                  B10

 

F4                     F2                     B6                     B8


 

 

Figure 2

 

L3                      L1                   R7                      R9

 

 

L5                      Road                      R10

 

L4 L2 R6 R8

 

LIST OF TABLES 

Table 1 - List of ants found in urban area of El Paso.

Table 2 - List of ants found in desert area of El Paso.

Table 1

Genera

 

Percent

Dorymyrmex sp.

 

7

Forelius sp.

 

24

Formica sp.

 

1.3

Monomorium sp.

 

4

Myrmecocystus sp.

 

0.32

Paratrechina sp.

 

3

Pheidole sp.

 

13

Pogonomyrmex sp.

 

8

Solenopsis sp.

 

40

Trachymyrmex sp.

 

0.16


Table 2

Genera

 

Percent

Aphaenogaster sp.

 

1.8

Conomyrmex sp.

 

14

Forelius sp.

 

41

Formica sp.

 

3.4

Monomorium sp.

 

1.5

Myrmecocystus sp.

 

0.9

Pheidole sp.

 

9

Pogonomyrmex sp.

 

15

Solenopsis sp.

 

13

Trachymyrmex sp.

 

0.6

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