Solenopsis richteri, full face view of a major worker, note the black scapes
click image to enlarge). |
Solenopsis richteri, profile view of a major worker
click image to enlarge). |
Solenopsis richteri, full face view of a major worker, note the black scapes
click image to enlarge). |
Solenopsis richteri, profile view of a major worker
click image to enlarge). |
Solenopsis richteri, profile view of a minor worker
click image to enlarge). |
Solenopsis richteri, profile view of an alate male
click image to enlarge). |
Introduction
Solenopsis richteri, commonly referred to as the black imported fire ant, is a serious econimic pest in both Mississippi and Alabama. Imported fire ant is a major agricultural and urban pest that also causes both medical and environmental harm resulting in a cost of many millions of dollars per year for southeastern states.
Identification
Solenopsis richteri can generally be recognized by their large mounds, polymorphic castes (varying sizes of workers), 10 segmented antennae ending in a 2 segmented club, lack of spines on propodeum, dark color, median tooth on the anterior border of the clypeus, humeral processes on major workers (lacking in S. invicta ) and a large reddish orange colored spot of the first segment of the gaster. However, because S. richteri hybridizes with S. invicta, it can be a challenge to differentiate them from the hybrid, which may have characters of both species. The most reliable method for identification of this group is a cuticular hydrocarbon test, which some labs are now equipped to do.
Biology and Economic Importance
The black imported fire ant is thought to have been introduced into the U.S. from South America, probably Argentina, sometime near 1918. The black impored fire ant along with Solenopsis invicta, the red imported fire ant, which was introduced sometime between 1933 and 1945, have wreaked havoc on the economy of the South. As if these two species were not bad enough, they both can mate with one another producing a hybrid, which is as bad or worse than either the black or red fire ant. Two native fire ants, S. geminata and S. xyloni, have not been collected in either MS or AL in many years and it is thought that the two imported fire ants and their hybrid have out-competed them for resources and effectively driven them out of this area.
Distribution
Distributionally, S. richteri tends to be found in the northeastern part of MS and northwestern portions of AL, and northward into TN; whereas, S. invicta is found in the southern halves of both AL and MS and also found in the western portion of MS following the Mississippi River northward (also in several other states), with the hybrid found in a band between the two populations.
Literature Cited
Links
Extension Fire Ant Site- http://www.extension.org/fire+ants
Texas A & M Fire Ant Site- http://fireant.tamu.edu/
The Imported Fire Ant and Its Control - http://msucares.com/insects/fireants/index.html
Imported Fire Ants in Tennessee - http://fireants.utk.edu/
Imported Fire Ant and Household Insects (IFAHI) research site-http://www.ars.usda.gov/Main/site_main.htm?modecode=66-15-10-15
LSU red imported fire ant research- http://www.lsu.edu/ants/index.shtml
Control of the Red Imported Fire Ant -http://www.ces.ncsu.edu/depts/ent/notes/Urban/ifa.htm
List of Fire Ant Web Page Links - http://hbs.bishopmuseum.org/ants/Solenopsis/Sollinks.html |
