Table 1.  Number of species per subfamily and genus per state

The total number of species per subfamily and genus for all eight Midwestern states together as well as for the Nearctic region (Bolton 1995 and Bolton 1999 for Pyramica) are also listed.  Finally, at the bottom, the total number of species is listed, for each state, all eight Midwestern states together, and the whole Nearctic region (Bolton 1995). 

 

 

 

Table 2.  Most speciose genera of the Midwest and the whole Nearctic (Bolton 1995 and Bolton 1999 for Pyramica)

 

 

State abbreviations are:  IA (Iowa), IL (Illinois), IN (Indiana), KS (Kansas), MI (Michigan), MN (Minnesota), ND (North Dakota), SD (South Dakota).  The data for the number of species collected in each Midwestern state are from the ‘Distribution of ants in the Midwestern USA’ webpage at this site.  The database is based on published species lists from seven Midwestern states:  Iowa (Buren 1944), Illinois (DuBois & LaBerge 1989), Indiana (Morris 1943, Munsee, et al. 1986), Kansas (Dubois 1985, Dubois & Danoff-Burg 1994), Michigan (Wheeler et al. 1994), North Dakota (Wheeler & Wheeler 1963, 1977), and South Dakota (Wheeler & Wheeler 1987), as well as Minnesota (present study – ‘Preliminary list and distribution of the ants of Minnesota’).

                Tables 1 and 2 allow a comparison of the number of species collected between states, all the Midwestern states together, and the whole Nearctic region.  Approximately 43% (236) of the 555 Neartic ant species are found in the Midwest.  Wheeler & Wheeler (1986, page 105), starting with the assumption that there are 578 Nearctic species, state:

 

“If, however we deduct the 80 rare species that have been collected only once (known only from type material) or in only one place (known only from type locality) and also the 115 species collected only in the Gulf and Border states (Florida to California), wich are essentially tropical, the remaining 383 are species which myrmecologists might expect to collect in the temperate part of the Nearctic Realm.”

 

Following this logic, approximately two-thirds [236 / (555 - 80 -115) = 236 / 360] of temperate Neartic ants are found in the Midwest.

                It is interesting to note which genera are most speciose in the Midwest compared with the whole Nearctic (Table 2).  Formica is the most speciose genus in the Midwest and the rest of the Nearctic and most Formica species (61/93) are found in the Midwest.  Similarly, most Nearctic Myrmica, Lasius, and Acanthomyops, and all Dolichoderus are found in the Midwest.  The remaining speciose genera listed in Table 2 are not especially well represented in the Midwest compared with the rest of the Nearctic.  Several of these genera (Camponotus, Pyramica, Pheidole, Crematogaster, Neivamyrmex, Pogonomyrmex) are much more speciose in the southern or western United States.  For example, most of the species of Neivamyrmex and Pogonomyrmex included in the Midwestern count were collected in Kansas. 

            Another trend is evident from table 1.  Over half of all Nearctic species in the subfamilies Formicinae and Dolichoderinae are present in the Midwest while approximately one third of all Nearctic species in the subfamilies Ecitoninae, Myrmicinae, and Ponerinae are present in the Midwest.  These data clearly show the dominance of the Formicinae, particularly Formica, in the Midwest.  The abundances of Midwestern ant taxa follow a similar trend: Formica, Lasius, and Camponotus seem to be the most abundant genera in all areas of the Midwest.