67 ECOLOGICAL DISTRIBUTION OF ACRIDIDAE IN CENTRAL OKLAHOMA· CHARLES C. SMITH, Norman This report is a summary ot some ot the results ot studies dealing with biotic communities in central Oklahoma during 1938 and 1939. Only the data dealing with the Acrididae are included here. Complete reports are being pnblished elsewhere. It is ot practical importance tor the ecologist and the entomologist to know the correlation between various habitats and the distribution of species of Insects. From the standpoint ot community ecology, grasshop­ pers constitute an important component ot the tauna, since they have a direct influence on the plant life and provide tood for other animals ot the community. They constitute an important link in the transformation of plant tissues into animal material usable by other animals. In this study, quantitative collections and field observations were made of the grasshoppers in a number of different habitats. The data are summarized in Table 1, which is largely self explanatory. Well rec­ ognized communities are named from the dominant plants. Others are given a descriptive name. Climax situations yield a larger number of species but a smaller number of specimens than disturbed areas or seral stages. Overgrazed pastures in this region often show a type of vegetation similar to that of the short grass plains farther west and also an assemblage of grass­ hoppers of western affinities. At the same time many ot the eastern species found in the mixed-grass prairie survive in overgrazed areas and these, in addition to geophilous species which increase in number, cause an increase both in species and specimens from such areas. In 1938, from normal, undisturbed prairie, there were taken 25 species and 649 speci­ mens, from overgrazed areas, 35 species and 1746 specimens. Midseral stages in succession showed a much higher number of specimens than either pioneer communities on abandoned, eroded land or climax prairie. From pioneer stages were taken 14 species and 327 specimens, from mid­ seral communities 22 species and 814 specimens and as was mentioned above, 25 species and 649 specimens from the native prairie. Bunch-grass sand-prairie yielded the largest number ot specimens ot any ot the stations in 1938, 18 species and 2154 specimens being taken there. Some species ot grasshoppers are governed in their distribution by the character ot the soil surface, that is, whether exposed or covered by vegetation, and the physical character of the soil, that is, whether loam, fine sand, coarse sand or clay. Other species are associated with certain species of plants and are distributed in accordance with these plants. Still others are limited in their distribution by a combination of the factors mentioned. Difference in plant communities under the same climatic con­ ditions is usually due to edaphic factors. As is 11lustrated in Table 1, most species are associated with speciflc types of plant associations al· though they may be present in small numbers In other communities. The work of Vestal (1913) on the local distribution of grasshoppers In rela- • Contribution No. 223 from the Zoological Laboratories, University ot Ok­ lahoma. .8 PROCEEDINGS OIo~ THE OKLAHOMA tfOD to plant auocJatlons showed that certain species are more restricted In rauce of habitats than are others. He found that no two plant asso­ CIaU0D8 bad Identical graubopper assemblages and that no two grass­ hoppen have Identical habitat preferences. 11817 (1937) .tudied the seaaonal succession and BOil relations of north­ eutern Teus acridlans and found that in certain instances succession is determined b7 specific food plants but chiefly Is determined by Interrela­ tlou re-ultlng from vegetation cover and climate. In other words grass­ hoppers are a part of the biotic community in which they occur and their preaence i8 due to factors of the habitat. Weue (1939), Smith (1940). and Coyner (1939) have shown that when overgrazing bas eliminated the taller components of the mixed-grass prairie, ,hort grasses become dominant and that species of acridians char­ acter1ltic of the short-grass plains to the west invade and become import­ ant. Oeophllous species al80 increase in abundance because of the in­ crease in the total amount of exposed soil surface. Smith (1940) traced biotic succession on abandoned. eroded farmland and found that Melanophl" cU!1erenUali8 was the most important acridian In pioneer communitlee. M. conlt1.BtU. Mermjrta mac1IUpennia and Hippi8CV8 nt,go.G in midseral stages and 8l1rbtda aclmtrabiliB, M. con!us1ls and M. jHlCkclrcJ" in the mixed-grass prairie cUmax community. The eeaaonal succession of most acridians found in the prairie region of central Oklahoma was followed by Acker (1939) who also made obser­ vations on the ecological distribution of the various species. BIBLIOGRAPHY Acker, G.. 1939. Seasonal succession of grasshoppers in central Oklahoma. Theeis, University of Oklahoma. Coyner. W•• 1939. Effect ot overgrazing on the acrididae. Proc. Okla. Acad. Sci. 19:83-86. IlelY. F. B.. 1987. Seasonal succession. soil relations. numbers and regional distribution ot northeastern Texas acridians. Ecol. Mon. 7:319­ 3.3. Smith, C. C.. 1940. Biotic and physiographic succession on abandoned eroded farmland in central Oklahoma. Ecol. Mono. 10. No.3, (in press) Smith, C. C.. 19.0-6. The effect of overgrazing on the biota of the mixed­ grass prairie in Oklahoma. Ecology 21, (in press) Vestal, A. G., 1913. Local diBtribution of grasshoppers in relation to plant &88OClatfons. Bio. Bull. 26:H1-180. Weese, A. 0., 1939. The effect of overgrazing on insect populations. Proc. Okla. Acad. Set 19:96-99. ACADEKY OF SCIENCE FOR 111. TABLE 1 EcoJoI/kal (Jutriklto. 01 '''e wno.. a~ 01 AcridUGe 'ft cnt,.., OWGAowa. ABCDEFGHIJKLKN PBoloessa texana (Scudder) 3 J 1 Dlchromorpha viridis (Scudder) 321 Schlstocerca damnttica Sau88ure 3 Schistocerca americana (Drury) 2 2 1 131 2 1 Arphla xanthoptera (Burme18ter) 3 2 2 1 1 2 Acrolophitls hirtlpes (Say) 3 2 2 2 2 1 2 Chortophaga viridttasciata (De Geer) 3 1 1 1 1 3 Hlppiscus rugoeus (Scudder) 1 Z 1 2 1 8 1 a Pardalophora sau88urel (SCudder) 1 1 2 3 2 1 2 1 3 1 Arphla simplex Scudder 1 2 3 1 1 1 1 1 2 J Melanoplu8 t.r. femur rubrum (De Geer) 3 2 2 1 Melanoplus keelerl (Thomas) 3 Melanoplus contusus Scudder 2 2 2 8 2 2 3 3 2 1 Melanoplu8 packardU Scudder 2 2 3 3 2 2 2 1 Melanoplus foedu8 fiuviatllis Bruner 2 2 1 1 1 3 Melanoplu8 blvittatus (say) 132 1 221 2 Melanoplus ponderosu8 (Scudder) 822 Melanoplus bispmosu8 SCudder III Melanoplus mexicanus (sau88ure) 1 1 3 Melanoplus angustipenni8 Implger Scudder 3 1 311 Melanoplus regalfs (Dodge) 132 MelanopluB dlfferentia118 (Thomas) 1 121 1 a 1 Amphltornus c. coloradus (Thomas) 2 3 2 2 Leprus wheelerl (Thomas) 2 1 Hesperotettlx viridis pratensis Scudder 2 2 1 2 Hesperotettlx speclosus (Scudder) 1 1 1 133 2 1 Hesperotettlx v. viridis (Tbomas) 1 2 3 2 1 2 1 Opeia o. obscura (Thomas) 3 2 1 a Boopedon gracile Rehn 2 2 3 2 Orphulelia speclosa Scudder 2 2 3 2 1 2 2 Syrbula admlrabUis (Uhler) 2 2 a 2 2 2 1 1 8 Mermirta maculfpennls Bruner 232 2 2 2 1 2 1 .Agenotettlx d. deorum (Scudder) 1 2 3 2 121 3 Eritettix simplex (Scudder) 2 2 Dissostelra carolina (Linnaeus) 1 2 1 Diss08telra longJpennis (Thomas) 2 1 Pblltbostroma quadrlmaculatum 2 3 3 (Thomas) Brachystola magna (Girard) 2 3 Spharagemon equale (Say) 3 1 3 1 222 Spharagemon collare (Scudder) 2 3 2 2 223 Hadrotettlx trlfasciatus (Say) 3 2 1 2 2 Arphia consperaa Scudder 3 213 Trlmerotropls p. pallldipennis 2 1 (Burmeister) Trachyrhachls kiowa fuscUabrls 2 3 (Thomaa) Schistocerca lIneata SCudder 1 2 2 3 Schistocerca obscura (Fabricius) 2 LeptyBma ma.rg1nicoUis (8ervI11e) a Paratettlx cucullatus (Burmelater) 8 ( A) saftiiD&ii (QUercu-mckoi'l&-ADdropogon auoctation). (ti) Mid-cra- prab18 (ARdropo,ma aCOJ)Clnu-BotJtelotwJ e-rtlpendtd4 auoclatlon), (0) JIUu4-cra­ prairie (A. aCOj'HJriu- B. c.rllpett4wl4-B. Mra.t4-Bucbloe aMOCIatlon), .(D) OYer­ grued pastures (B. hirnt4-Buchloe-Amphlachyr1e), (E) Short-grau pralrle (B. " ....t4-Buehloe), (F) Subcllmu pralrte (Andropogon colUlOClee), (0) Seral stagee on eroded B011 (AriaUda ueoeIee), (H) Pioneer stag.. on eroded 100 (lOIed-weed aaoctes), (I) Bunch-grasa 8and-pralrte (Panlcum-Androposon .... elation) (J) Sandy flood plabul (Tamarlx-8al1x aMOCIes), (K) 8edce flag, (L} Water's edp, (M) Pioneer stage on uneroded eo11, (N) Bermuda ...... aod..