Tetramorium rhenanum |
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Urban and suburban habitats of the St. Louis, Missouri Metropolitan Area are overrun by a small Tetramorium, that for years I took to be the Tetramorium caespitum equivalent of the polygyne fire ant. I discovered through Bernhardt Seifert's "Ameisen" that this little polygyne Tetramorium is the recently described, Central European, xeric limestone grassland species, T. rhenanum.
The T. rhenanum invasion has spread from St. Louis City to the surrounding County and to parts of adjacent Jefferson, Franklin and St. Charles Counties in Missouri and Marion and Madison Counties in Illinois. It also seems to have made it out to the town of Columbia, Callaway County, Missouri. While mostly restricted to human habitat, in southern St. Louis and northern Jefferson Counties, I have found it in a type of Ozark Hills xeric calcareous grassland, known as dolomite glade. Everywhere I have found it, this ant has largely displaced almost all native ants larger than itself, leaving only arboreal Camponotus, Tapinoma sessile, minute Myrmicinae, such as Leptothorax, Solenopsis and Monomorium, and subterraneans such as Ponera and Brachymyrmex. It is very hard on Formica, Myrmica, Aphaenogaster and less certainly on Lasius and Crematogaster.
A tropical Tetramorium, T. bicarinatum is a free-living resident at the Sophia M. Sachs Butterfly House and the St. Louis Zoo Insectarium. T. bicarinatum occurs along with Paratrechina bourbonica at the Butterfly House, and P. bourbonica is also resident at the Missouri Botanical Garden Climatron without the accompanying T. bicarinatum. The ants in these tropical conservatories have certainly come in with the nursery stock from Florida that is planted in them.
James C. Trager, Ph. D.
Shaw Nature Reserve
created: 16 April 2002 updated:Tuesday, April 16, 2002 Contributors: Trager Page author: McGlynn