Data are presented on the discovery of a large number of undisturbed colonies of mound building ants and the ecological conditions of their development

Christensen, C. L.

Quick, K. M.

University of Northern Iowa

Proceedings of the Iowa Academy of Science Volume 77 Annual Issue Article 31 1970 Report on Formica exsectiodes Forel in Hamilton County C. L. Christensen Iowa Central Community College K. M. Quick Let us know how access to this document benefits you Copyright ©1970 Iowa Academy of Science, Inc. Follow this and additional works at: https://scholarworks.uni.edu/pias Recommended Citation Christensen, C. L. and Quick, K. M. (1970) "Report on Formica exsectiodes Forel in Hamilton County," Proceedings of the Iowa Academy of Science, 77(1), 207-209. Available at: https://scholarworks.uni.edu/pias/vol77/iss1/31 This Research is brought to you for free and open access by the Iowa Academy of Science at UNI ScholarWorks. It has been accepted for inclusion in Proceedings of the Iowa Academy of Science by an authorized editor of UNI ScholarWorks. For more information, please contact scholarworks@uni.edu. Report on Formica exsectiodes F orel in Hamilton County C. L. CHRISTENSEN1 and K . M. QurcK Abstract. Data are presented on the discovery of a large number of un-disturbed colonies of mound building ants and the ecological conditions of their development. The discovery of the eastern mound-building ant in Hamilton County was unexpected. It was also amazing to see the extent of development and the number of mounds. Iowa records (Buren, 1944) indicate identification of this species, Formica exsectoides, Forel, at Inwood, Denison and Mount Vernon. These reports were all made from single, small and apparently struggling colonies. Formica exsectoides, more commonly called the eastern or Al-lieghery mound builder, forms an aggregate of colonies consisting of numerous mounds in open forest clearings. The average mound constructed by these ants is about two feet high and up to six feet across. The ants work the ground to a depth of more than five feet. The complex of ant mounds studied for this report is located about 7Y2 miles south and 11'2 miles west of Webster City, Iowa. They are found grouped in the clearings of a dense oak-hickory Figure 1. Aggregate of ant mounds in an open forest clearing. 1 Iowa Central Community College, Webster City, Iowa 50595 . 207 1Christensen and Quick: Report on Formica exsectiodes Forel in Hamilton CountyPublished by UNI ScholarWorks, 1970208 IOWA ACADEMY OF SCIENCE [Vol. 77 forest on the upland plains overlooking the Boone River. It must be noted heve that this area is on Litchfield property and that per-mission was obtained before this study was begun. The legal loca-tion of the area is the center of section 15, T-87-N, R-26-W, Web-ster Township, Hamilton County, Iowa. A number of the ants were collected and tentatively identified. Later some were sent to the University of Nevada to verify the specific epithet. The next part of the study involved the mapping and measuring of the mounds. \Vhat appeared to be a "typical" clearing was designated "A", and the mounds present were numbered in order from the largest to the smallest in height. Diameter and circumference were re-corded along with the general appearance of the mound. Where the mound was oblong, in place of round, both long and short axes were measured. Table I. Measurements and Condition of the Ant Mounds as Observed in Clearing A. November 1969. Mound Number A-1 A-2 A-3 A-4 A-5 A-6 A-7 A-8 A-9 A-10 Height Diameter Circum-ference Remarks 68 cm 47.3 cm 42.6 cm 403 cm (287 cm) 1072 cm largest 223.2 cm ( 153 cm) 550 cm enlarging 197.6 cm 577 cm rapid 38.1 cm 126.2 cm 37.1 cm 204.3 cm 27.4 cm 132.5 cm 25.4 cm 97.1 cm 23.0 128.2 cm 21.3 cm 123.2 cm 12.0 cm 43.4 cm development 46 7 cm most active mound 540 cm becoming inactive 472 cm dead, inactive 311 cm 44 7 cm damaged by horses-still active 434 cm 1 71 cm started spring '69 A second clearing was designated "B", and the whole opera-tion was repeated. Because of the large number of mounds present, several hundred, the mapping, measuring and describing of all of the mounds is still incomplete at this time. Results, at this early date, are inconclusive but some observa-tions can be veported. Active mounds are located only where there is a clear unobstructed view of the sky directly overhead. If a tree branch or other obstruction moves in such a way as to cover the top of the mound at any height, activity slows and the mound degenerates rapidly. Should the obstruction remam for a long • 2Proceedings of the Iowa Academy of Science, Vol. 77 [1970], No. 1, Art. 31https://scholarworks.uni.edu/pias/vol77/iss1/311970] MOUND-BUILDING ANTS 209 period of time (several months), the colony dies out or migrates. Evidence as to which happens is insufficient to permit a positive statement, but, at any rate, the mound becomes inactive. Another cause for the degeneration of a colony is disturbance of the mound. At this time cattle, horses, and motorcycles running over the mounds cause the greal!est damage. When this happens and damage results, at first there is great activity and then the whole colony appears to enter a state of shock and all activity stops. If enough damage is done the colony does not make a comeback and mound development ceases. The formation of a new clearing, resulting from trees falling down for one reason or another, is followed by a great deal of ant activity. Colonies move into the area and mound building prog-resses at a rapid rate. This observation was made after a wind storm blew over trees in the early spring of 1969. The following summer produced much activity in these areas. We, The authors now realize that this study will require many years to complete. It is hoped that conditions will remain such that the ant hills can be protected from man's "progress". To our knowledge, this is the only large complex of several hundred col-onies of Formica exsectoides Fore! reported in Iowa. We wish to thank Professor A. C. Haman, Biology Department, University of Northern Iowa for his guidance and encouragement in the development of this study. We also desire to express our sincere thanks to Dr. G. C. Wheeler, Desert Research Institute, Reno, Nevada for his identification of Formica exsectoides Forel. Bibliography ANDREWS, E. A. 1926. Psyche 33: 127-150. BuREN, W. F. 1941. Iowa State Coll. ]. Sci. 15(2) : 111-117. ------· 1944. Iowa State]. Sci. 18:277-312. CoRY, E. N. & E. E. HAVILAND. 1938. Ann. Ent. Soc. Amer. 31: 50-57 CREIGHTON, W. S. 1950. Bull. Mus. Comp. Zoo!. Harvard. 104:513-515. DREYER, W. A. 1942. Ecology. 23: 486-490. HAVILAND, E. E. 1948. Ann. Ent. Soc. Amer. 41 :438. KING, R. L. & R. M. SALLEE. 1956. Proc. la. Acad. Sci. 63: 721-723. ____________ & . 1964. Proc. la. Acad. Sci. 71: 484-485. 3Christensen and Quick: Report on Formica exsectiodes Forel in Hamilton CountyPublished by UNI ScholarWorks, 1970

Report on Formica exsectiodes Forel in Hamilton County

Name not available

https://scholarworks.uni.edu/cgi/viewcontent.cgi?article=1831&context=pias

Report on Formica exsectiodes Forel in Hamilton County

Abstract

Similar works

Full text

Available Versions

University of Northern Iowa

Name not available