Of 64 species of spiders taken from the ground stratum of an Arkansas pasture and adjoining cotton field, only 26 were common to both. Twenty-two were collected only in the cotton field; 16, only in the pasture. Many of the 18 species of lycosids were taken in greater numbers in the cultivated field, especially Pardosa milvina and Lycosa helluo. Eight species of lycosids were found only in the cotton field; two, only in the pasture. Only Schizocosa avida, of the better represented lycosids, appeared to show no preference. Similar relationships are given for dictynids, erigonids, linyphiids, oxyopids, gnaphosids, clubionids, thomisids, and salticids

Exline, Harriet

Hite, Maxine

Whitcomb, W. H.

English

ScholarWorks@UARK

Journal of the Arkansas Academy of ScienceVolume 17 Article 81963Comparison of Spider Populations of GroundStratum in Arkansas Pasture and AdjacentCultivated FieldW. H. WhitcombUniversity of Arkansas, FayettevilleHarriet ExlineCalifornia Academy of SciencesMaxine HiteUniversity of Arkansas, FayettevilleFollow this and additional works at: http://scholarworks.uark.edu/jaasPart of the Entomology Commons, and the Population Biology CommonsThis article is available for use under the Creative Commons license: Attribution-NoDerivatives 4.0 International (CC BY-ND 4.0). Users are able toread, download, copy, print, distribute, search, link to the full texts of these articles, or use them for any other lawful purpose, without asking priorpermission from the publisher or the author.This Article is brought to you for free and open access by ScholarWorks@UARK. It has been accepted for inclusion in Journal of the Arkansas Academyof Science by an authorized editor of ScholarWorks@UARK. For more information, please contact scholar@uark.edu, ccmiddle@uark.edu.Recommended CitationWhitcomb, W. H.; Exline, Harriet; and Hite, Maxine (1963) "Comparison of Spider Populations of Ground Stratum in ArkansasPasture and Adjacent Cultivated Field," Journal of the Arkansas Academy of Science: Vol. 17 , Article 8.Available at: http://scholarworks.uark.edu/jaas/vol17/iss1/8Arkansas Academy of Science Proceedings, Vol. iy, 1963COMPARISON OF SPIDER POPULATIONS OFGROUND STRATUM IN ARKANSAS PASTURE ANDADJACENT CULTIVATED FIELD ••»W. H. Whitcomb 3, Harriet Exline4, and Maxine Hite8ABSTRACT. Of 64 species of spiders taken from the groundstratum of an Arkansas pasture and adjoining cotton field, only26 were common to both. Twenty-two were collected only inthe cotton field; 16, only in the pasture. Many of the 18 spe-cies of lycosids were taken in greater numbers in the cultivatedfield, especially Pardosa milvina and Lycosa helluo. Eightspecies of lycosids were found only in the cotton field; two,only in the pasture. Only Schizocosa avida, of the better repre-sented lycosids, appeared to show no preference. Similar rela-tionships are given for dictynids, erigonids, linyphiids, oxy-opids, gnaphosids, clubionids, thomisids, and salticids.No one in North America, as well as can be learned, hascompared the spider population of a natural or nearly naturalplant community with that of an adjacent cultivated field. Ofthe numerous recent surveys of particular habitats, many in-clude comparisons of populations of spiders in various strata,and a few deal with faunal changes following plant succes-sion: deciduous forest succession by Smith-Davidson (1932);plant associations, Presque Isle, Lake Erie, by Truman (1942) ;Chicago area dunes by Lowrie (1948); virgin prairie nearLincoln, Nebraska, by Muma and Muma (1949) ; and mari-time plant communities by Barnes (1953).A pasture and adjacent cotton field were selected forstudy, situated on bottom land and river terrace on the southside of the Arkansas River, near Morrilton, Conway County,Arkansas. The pasture undulates and slopes toward the nearlyflat cotton field below, its highest point being about 20 feetabove the field. The pasture is essentially a Bermuda grass,Cynodon dactylon (Linn.), community; but other plants, suchas dog fennel, Anthemis spp., and bitterweed, Helenium tenui-folium Nutt., are present. Cattle graze it, disturbing anddestroying some of the spider population, especially that of theherbaceous stratum. The cotton field, once part of the pasture,•Partially supported by N.S.F.G. —175 64.with the approval of the Director of the Arkansas AgriculturalExperiment Station.3Professor, University of Arkansas.*Mrs. D. L. Frizzell, Rolla, Missouri; Research Associate, California Acad-emy of Sciences.Research Assistant, University of Arkansas.34Journal of the Arkansas Academy of Science, Vol. 17 [1963], Art. 8Published by Arkansas Academy of Science, 196335Spider Faunalas been plowed and planted for two years. Itlies fallow dur-ng the winter and is thoroughly disked and cultivated. Suchultivation destroys many spiders each winter, so that much ofhe summer fauna apparently originates in outside sources aftereach spring planting.The objective in selecting the ground stratum in these en-vironments was chiefly to investigate the incidence of wolfpiders (Lycosidae) that, in the preliminary surveys of 1960and 1961, had appeared to be more numerous on cultivatedhan uncultivated land. The authors hoped to learn, by samplinghe ground stratum of adjoining field and pasture, whether cer-ain lycosid species show a distinct preference for one environ-ment or the other.MethodsPitfall traps were used, a modification of the type em->loyed by Hensley and associates (1961). Each consists of ajuried metal sleeve supporting a quart jar; the jar ring is sol-dered to a quarter-inch rim, that rests on the sleeve. A metalhield above excludes rain and debris. This construction per-mits emptying the trap with minor disturbance to the soil andprevents spiders from falling between jar and sleeve. Thesesmall traps were used in preference to the larger models ofFichter (1941) and Rhoades (1962), because they could beset in drill rows of the cotton field, without curtailing currentfarm practices, and in the pasture they were less liable to dis-turbance by livestock.Thirty traps were emplaced, 10 in the cotton field and 20in the pasture, and collections were made weekly from June10 to September 1, 1962. Jars were filled a quarter to a thirdtheir depth with 70 per cent alcohol. When specimens were re-aoved, they were transferred to 95 per cent alcohol for stor-In computing relative numbers of specimens in collectionsfrom the two environments, a base of 10 traps was used.Therefore, actual counts for the 20 traps of the pasture havebeen divided by two in Table 1.ResultsSixty-four species of spiders were collected, during theummer of 1962, from the ground stratum in the pasture andadjacent cotton field. Twenty-six were common to both areas;22 were taken only in the cotton field; and 16, only in thepasture. More wolf spiders (Lycosidae) were taken than mem-)ers of any other family, and there were more species repre-ented. Distribution of all species is shown in Table 1.35Journal of the Arkansas Academy of Science, Vol. 17 [1963], Art. 8http://scholarworks.uark.edu/jaas/vol17/iss1/8Arkansas Academy of Science ProceedingsPreference for field or pasture was strikingly demonstrat-ed by most species of lycosids. Only Schizocosa avida and Par-dosa saxatilis "var. atlantica" were collected in approximatelyequal numbers in both environments. Arctosa funerea and Ly-cosa antelucana were taken only in the pasture. Pardosa paux-illa and Lycosa rabida were taken somewhat more frequentlyin the pasture. Lycosa punctulata, L. helluo "var. annexa,"Pardosa saxatilis s. s., Pirata minutus, P. n. sp. A, P. aff. in-sularis, and P. sedentarius, were collected only in the cottonfield. Pardosa milvina, Pirata sylvanus, Pirata n. sp. B, andLycosa helluo s.s. were many times more numerous in traps inthe cotton field than in the pasture.Erigonids appeared to prefer the cultivated field. Gram-monota inornata, Erigone autumnalis, and Walckenaera vigi-lax, represented in both areas, were taken in greater numbersin the cotton field; and Eperigone aff. tridentata, E. tridentata,E. maculata, and Floricomus sp. were found only there.Species of Dictyna, which usually build webs high on her-baceous plants, are not ordinarily taken in pitfall traps. Dic-tyna segregata, however, was fairly numerous in samples fromthe cotton field, although it was not taken in the pasture.Several more species were far more common in collectionsrom the pasture. The lynx spider, Oxyopes aff. helius, is themost unexpected of these, as members of this genus live most-y on foliage of shrubs and are taken by sweeping or plantexamination, almost never in pitfall traps. Only very immaturepecimens of O. aff. helius had been taken previously in Ar-cansas, and then only by sweeping. Meriola decepta, a clubio-nid commonly living in ground litter, was more numerous inhe traps in the cotton field, and the gnaphosid, Drassyllus me->histo, was more numerous in the traps in the pasture. Theatypical linyphiid,Tennesseellum formicum, was collected onlyn the pasture.Species of several families which might have been expectedto give comparative data were useless, because no adults werebund, and the immature forms are unidentifiable: Clubiona,agelenids, and theridiids. Identification of several species is ten-ative because of the poverty of taxonomic literature, limitedcollections, and incomplete knowledge of the fauna.DiscussionSignificant differences in the spider population of thejround stratum of these two concrete and adjacent communi-ies (see Barnes, 1953; Barnes and Barnes, 1955) are appar-nt. Obviously, the data and collections are too limited to per-mit generalizations that would apply to similar abstract com-munities, where populations may be quite different. Also, dif-36Journal of the Arkansas Academy of Science, Vol. 17 [1963], Art. 8Published by Arkansas Academy of Science, 1963Spider FaunaIrent results would be likely if the herbaceous, instead of theound stratum, were examined. Preliminary sampling of thermer by sweeping, showed a more numerous spider popula->n in the pasture. In the ground stratum, the population ofe cotton field appeared to be considerably larger. Populationsthe two strata reflect a difference in their faunas. Sweepingsthe herbaceous stratum collect web-builders, as Tetragnathabrriosa Hentz, and hunting spiders living in foliage, includ-g Oxyopes salticus, some salticids, thomisids, and clubionidsreported by Whitcomb, Exline, and Hunter (1963). Pit-II trap collections of the ground stratum, in contrast, containiders which live in litter, as Meriola decepta, and those whichmt most of their prey on the ground, including most lycosidsd some gnaphosids. There is some overlapping: litter-in-biting spiders are sometimes swept from foliage, and spidersthe herbaceous stratum are sometimes collected in pitfalltSome differences noted in the spiders of the ground stratumthe pasture and cotton field may be explained by physicaltors. Species of Pirata and the erigonids were found in con-erably greater numbers in the cotton field, perhaps becausefield is lower, and the soil therefore more moist.tThe appreciable number of specimens of Dictyna segre-a collected from traps in the cotton field was unusual for3 genus. Most species of Dictyna live high on herbs andubs and are not usually trapped on the ground. However,litcomb, Exline, and Hunter (1963) reported that D. segre-a was found close to the ground.IThe tremendous quantity of specimens of Pardosa milvinalected in the cotton field, 472 specimens per 10 traps, corn-ed to 1.5 specimens in the pasture, is unexplained except intns of preference or food supply. Lycosa helluo also was manyles more numerous in the traps in the cultivated field.(An interesting anomaly is noted in the occurrence of Par-sa saxatilis s. s. and P. saxatilis "var. atlantica," which usual-are not separated taxonomically. P. saxatilis s. s. was takenlyi the cultivated field; P. saxatilis "var. atlantica" was col-ted in approximately equal numbers in both environments.EIlBLE 1. Comparison of spiders taken per 10 pitfall traps inund stratum of pasture and adjacent cotton field near Mor-on, Arkansas, 1962.CultivatedDictynidae Pasture FieldIDictyna segregata Gertsch & Mulaik 0.0 21lyphiidaeMeioneta micaria (Em.) 0.0 1Mcioneta sp. 0.5 337Journal of the Arkansas Academy of Science, Vol. 17 [1963], Art. 8http://scholarworks.uark.edu/jaas/vol17/iss1/8Arkansas Academy of Science ProceedingsCultivatedFieldPasture1.5Tennesseellum formicum (Em.)Lepthyphantes sp.070.5ErigonidaeErigone autumnalis Em.Eperigone tridentata (Em.)Eperigone aff. tridentata (Em.)Eperigone maculata (Banks)Eperigone sp.1.5 300.0 10.0 220.0 60.5 1Ceraticelus sp.Floricomus sp.3.0 10.0 1Grammonota inornata Em.Walckenaera vigilax (Blackwall)20.5 321.0 6TheridiidaeLatrodectus sp.Theridion sp.0.5 \0.0ArgiopidaePachygnatha tristriata C. L.KochMimognatha foxi (McCook)1.0 \0.5AgelenidaeAgelenopsis sp.Cicurina sp.0.51.536.00.02.04.00.07.0%LycosidaeSchizocosa avida (Walck.)Schizocosa sp.342Arctosa funerea (Hentz)Lycosa rabida Walck.Lycosa punctulata Hentz023Lycosa antelucana MontgomeryLycosa helluo Walck.04.5 96Lycosa helluo "var. annexa Ch. & Ivie'Pardosa saxatilis (Hentz)0.0 130.0 4Pardosa milvina (Hentz) 1.5 472Pardosa pauxilla Montgomery 38.0 24Pardosa saxatilis "var. atlantica Em."Pirata minutus Em.7.0 100.0 3Pirata n. sp. A. 0.0 2Pirata sylvanus Chamb. & IviePirata aff. insularis Em.0.5 220.0 1Pirata sedentarius MontgomeryPirata n. sp. B.0.0 10.5 5OxyopidaeOxyopes salticus Hentz 1.026.000Oxyopes aff. helius Chamb.GnaphosidaeDrassyllus creolus Chamb. & Gertsch 0.0 138Journal of the Arkansas Academy of Science, Vol. 17 [1963], Art. 8Published by Arkansas Academy of Science, 1963Spider FaunaCultivatedPasture FieldDrassyllus mephisto Chamb. 7.0 0Drassyllus aff. fallens Chamb.. 0.0 1Drassyllus sp. 0.5 4Geodrassus sp. 1.0 2Cylphosa sericata (L.Koch) 4.5 0Zelotes laccus (Barrows) 0.0 2lubionidaeMeriola decepta Banks 2.5 16Castianeira descripta (Hentz) 1.0 1Castianeira vulnerea Gertsch 0.5 0Castianeira longipalpus (Hentz) 0.0 2Castianeira sp. 0.5 5Scotinella formica (Banks) 1.5 0Clubiona abbotii L. Koch 0.5 1Clubiona sp. 1.0 12'homisidaeXysticus texanus Banks 1.5 2Xysticus auctificus Keyserling 0.5 0Oxyptila sp. 0.0 1Thanatus sp. 1.0 0alticidaeEris marginatus (Walck.) 0.5 0Habronattus coronatus (Hentz) 5.0 2Habronattus sp. 1.0 2Sitticus floridanus Gertsch &Mulaik 0.0 1Phidippus carolinensis Peck. & Peck. 0.0 1Literature CitedIrnes, Robert D. 1953. The ecological distribution of spiders in non-forest maritime communities at Beaufort, North Carolina. Ecol. Monogr.23: 315-337.Irnes, Robert D., and Betty Martin Barnes. 1955. The spider populationof the abstract broomsedge community of the southeastern Piedmont.Ecology 36 (4): 658-666.»:hter, Edson. 1941. Apparatus for the comparison of soil surface arthro-pod populations. Ecology 22 (3): 338-339.Jnsley, S. D., W. H. Long, L. R. Roddy, W. J. McCormick, and E. J.Concienne. 1961. Effects of insecticides on the predaceous arthropodfauna of Louisiana sugarcane fields. Jour. Econ. Ent. 54 (1): 146-149.twrie, D. C. 1948. The ecological succession of spiders of the Chicagoarea dunes. Ecology 29 (3): 334-351.tima, H., and Katharine E. Muma. 1949. Studies on a population ofpr irie spiders. Ecology 30 (4) : 485-503.fioades, W. C. 1962. A synecological study of the effects of the importedfire ant eradication program. Florida Ent. 45 (4): 161-173.tiith - Davidson, Vera. 1932. The effect of seasonal variability uponanimal species in total populations in a deciduous forest succession. Ecol.Monogr. 2: 306-323.»uman, L. C. 1942. A taxonomic and ecologic study of the spider faunaof Presque Isle. Pittsburgh Univ. Bull. 38 (2): 404-411.Bhitcomb, W. H., Harriet Exline, and Robert Hunter. 1963. Spiders ofthe Arkansas cotton field. Ann. Ent. Soc. America. 56 (5): 653-660.39Journal of the Arkansas Academy of Science, Vol. 17 [1963], Art. 8http://scholarworks.uark.edu/jaas/vol17/iss1/8

Comparison of Spider Populations of Ground Stratum in Arkansas Pasture and Adjacent Cultivated Field

UARK (University of Arkansas )

Journal of the Arkansas Academy of Science Volume 17 Article 8 1963 Comparison of Spider Populations of Ground Stratum in Arkansas Pasture and Adjacent Cultivated Field W. H. Whitcomb University of Arkansas, Fayetteville Harriet Exline California Academy of Sciences Maxine Hite University of Arkansas, Fayetteville Follow this and additional works at: https://scholarworks.uark.edu/jaas  Part of the Entomology Commons, and the Population Biology Commons Recommended Citation Whitcomb, W. H.; Exline, Harriet; and Hite, Maxine (1963) "Comparison of Spider Populations of Ground Stratum in Arkansas Pasture and Adjacent Cultivated Field," Journal of the Arkansas Academy of Science: Vol. 17 , Article 8. Available at: https://scholarworks.uark.edu/jaas/vol17/iss1/8 This article is available for use under the Creative Commons license: Attribution-NoDerivatives 4.0 International (CC BY-ND 4.0). Users are able to read, download, copy, print, distribute, search, link to the full texts of these articles, or use them for any other lawful purpose, without asking prior permission from the publisher or the author. This Article is brought to you for free and open access by ScholarWorks@UARK. It has been accepted for inclusion in Journal of the Arkansas Academy of Science by an authorized editor of ScholarWorks@UARK. For more information, please contact scholar@uark.edu. Arkansas Academy of Science Proceedings, Vol. iy, 1963COMPARISON OF SPIDER POPULATIONS OFGROUND STRATUM IN ARKANSAS PASTURE ANDADJACENT CULTIVATED FIELD ••»W. H. Whitcomb 3, Harriet Exline4, and Maxine Hite8ABSTRACT. Of 64 species of spiders taken from the groundstratum of an Arkansas pasture and adjoining cotton field, only26 were common to both. Twenty-two were collected only inthe cotton field; 16, only in the pasture. Many of the 18 spe-cies of lycosids were taken in greater numbers in the cultivatedfield, especially Pardosa milvina and Lycosa helluo. Eightspecies of lycosids were found only in the cotton field; two,only in the pasture. Only Schizocosa avida, of the better repre-sented lycosids, appeared to show no preference. Similar rela-tionships are given for dictynids, erigonids, linyphiids, oxy-opids, gnaphosids, clubionids, thomisids, and salticids.No one in North America, as well as can be learned, hascompared the spider population of a natural or nearly naturalplant community with that of an adjacent cultivated field. Ofthe numerous recent surveys of particular habitats, many in-clude comparisons of populations of spiders in various strata,and a few deal with faunal changes following plant succes-sion: deciduous forest succession by Smith-Davidson (1932);plant associations, Presque Isle, Lake Erie, by Truman (1942) ;Chicago area dunes by Lowrie (1948); virgin prairie nearLincoln, Nebraska, by Muma and Muma (1949) ; and mari-time plant communities by Barnes (1953).A pasture and adjacent cotton field were selected forstudy, situated on bottom land and river terrace on the southside of the Arkansas River, near Morrilton, Conway County,Arkansas. The pasture undulates and slopes toward the nearlyflat cotton field below, its highest point being about 20 feetabove the field. The pasture is essentially a Bermuda grass,Cynodon dactylon (Linn.), community; but other plants, suchas dog fennel, Anthemis spp., and bitterweed, Helenium tenui-folium Nutt., are present. Cattle graze it, disturbing anddestroying some of the spider population, especially that of theherbaceous stratum. The cotton field, once part of the pasture,•Partially supported by N.S.F.G. —175 64.with the approval of the Director of the Arkansas AgriculturalExperiment Station.3Professor, University of Arkansas.*Mrs. D. L. Frizzell, Rolla, Missouri; Research Associate, California Acad-emy of Sciences.Research Assistant, University of Arkansas.34Journal of the Arkansas Academy of Science, Vol. 17 [1963], Art. 8Published by Arkansas Academy of Science, 196335Spider Faunalas been plowed and planted for two years. Itlies fallow dur-ng the winter and is thoroughly disked and cultivated. Suchultivation destroys many spiders each winter, so that much ofhe summer fauna apparently originates in outside sources aftereach spring planting.The objective in selecting the ground stratum in these en-vironments was chiefly to investigate the incidence of wolfpiders (Lycosidae) that, in the preliminary surveys of 1960and 1961, had appeared to be more numerous on cultivatedhan uncultivated land. The authors hoped to learn, by samplinghe ground stratum of adjoining field and pasture, whether cer-ain lycosid species show a distinct preference for one environ-ment or the other.MethodsPitfall traps were used, a modification of the type em->loyed by Hensley and associates (1961). Each consists of ajuried metal sleeve supporting a quart jar; the jar ring is sol-dered to a quarter-inch rim, that rests on the sleeve. A metalhield above excludes rain and debris. This construction per-mits emptying the trap with minor disturbance to the soil andprevents spiders from falling between jar and sleeve. Thesesmall traps were used in preference to the larger models ofFichter (1941) and Rhoades (1962), because they could beset in drill rows of the cotton field, without curtailing currentfarm practices, and in the pasture they were less liable to dis-turbance by livestock.Thirty traps were emplaced, 10 in the cotton field and 20in the pasture, and collections were made weekly from June10 to September 1, 1962. Jars were filled a quarter to a thirdtheir depth with 70 per cent alcohol. When specimens were re-aoved, they were transferred to 95 per cent alcohol for stor-In computing relative numbers of specimens in collectionsfrom the two environments, a base of 10 traps was used.Therefore, actual counts for the 20 traps of the pasture havebeen divided by two in Table 1.ResultsSixty-four species of spiders were collected, during theummer of 1962, from the ground stratum in the pasture andadjacent cotton field. Twenty-six were common to both areas;22 were taken only in the cotton field; and 16, only in thepasture. More wolf spiders (Lycosidae) were taken than mem-)ers of any other family, and there were more species repre-ented. Distribution of all species is shown in Table 1.35Journal of the Arkansas Academy of Science, Vol. 17 [1963], Art. 8https://scholarworks.uark.edu/jaas/vol17/iss1/8Arkansas Academy of Science ProceedingsPreference for field or pasture was strikingly demonstrat-ed by most species of lycosids. Only Schizocosa avida and Par-dosa saxatilis "var. atlantica" were collected in approximatelyequal numbers in both environments. Arctosa funerea and Ly-cosa antelucana were taken only in the pasture. Pardosa paux-illa and Lycosa rabida were taken somewhat more frequentlyin the pasture. Lycosa punctulata, L. helluo "var. annexa,"Pardosa saxatilis s. s., Pirata minutus, P. n. sp. A, P. aff. in-sularis, and P. sedentarius, were collected only in the cottonfield. Pardosa milvina, Pirata sylvanus, Pirata n. sp. B, andLycosa helluo s.s. were many times more numerous in traps inthe cotton field than in the pasture.Erigonids appeared to prefer the cultivated field. Gram-monota inornata, Erigone autumnalis, and Walckenaera vigi-lax, represented in both areas, were taken in greater numbersin the cotton field; and Eperigone aff. tridentata, E. tridentata,E. maculata, and Floricomus sp. were found only there.Species of Dictyna, which usually build webs high on her-baceous plants, are not ordinarily taken in pitfall traps. Dic-tyna segregata, however, was fairly numerous in samples fromthe cotton field, although it was not taken in the pasture.Several more species were far more common in collectionsrom the pasture. The lynx spider, Oxyopes aff. helius, is themost unexpected of these, as members of this genus live most-y on foliage of shrubs and are taken by sweeping or plantexamination, almost never in pitfall traps. Only very immaturepecimens of O. aff. helius had been taken previously in Ar-cansas, and then only by sweeping. Meriola decepta, a clubio-nid commonly living in ground litter, was more numerous inhe traps in the cotton field, and the gnaphosid, Drassyllus me->histo, was more numerous in the traps in the pasture. Theatypical linyphiid,Tennesseellum formicum, was collected onlyn the pasture.Species of several families which might have been expectedto give comparative data were useless, because no adults werebund, and the immature forms are unidentifiable: Clubiona,agelenids, and theridiids. Identification of several species is ten-ative because of the poverty of taxonomic literature, limitedcollections, and incomplete knowledge of the fauna.DiscussionSignificant differences in the spider population of thejround stratum of these two concrete and adjacent communi-ies (see Barnes, 1953; Barnes and Barnes, 1955) are appar-nt. Obviously, the data and collections are too limited to per-mit generalizations that would apply to similar abstract com-munities, where populations may be quite different. Also, dif-36Journal of the Arkansas Academy of Science, Vol. 17 [1963], Art. 8Published by Arkansas Academy of Science, 1963Spider FaunaIrent results would be likely if the herbaceous, instead of theound stratum, were examined. Preliminary sampling of thermer by sweeping, showed a more numerous spider popula->n in the pasture. In the ground stratum, the population ofe cotton field appeared to be considerably larger. Populationsthe two strata reflect a difference in their faunas. Sweepingsthe herbaceous stratum collect web-builders, as Tetragnathabrriosa Hentz, and hunting spiders living in foliage, includ-g Oxyopes salticus, some salticids, thomisids, and clubionidsreported by Whitcomb, Exline, and Hunter (1963). Pit-II trap collections of the ground stratum, in contrast, containiders which live in litter, as Meriola decepta, and those whichmt most of their prey on the ground, including most lycosidsd some gnaphosids. There is some overlapping: litter-in-biting spiders are sometimes swept from foliage, and spidersthe herbaceous stratum are sometimes collected in pitfalltSomedifferences noted in the spiders of the ground stratumthe pasture and cotton field may be explained by physicaltors. Species of Pirata and the erigonids were found in con-erably greater numbers in the cotton field, perhaps becausefield is lower, and the soil therefore more moist.tTheappreciable number of specimens of Dictyna segre-a collected from traps in the cotton field was unusual for3 genus. Most species of Dictyna live high on herbs andubs and are not usually trapped on the ground. However,litcomb, Exline, and Hunter (1963) reported that D. segre-a was found close to the ground.IThetremendous quantity of specimens of Pardosa milvinalected in the cotton field, 472 specimens per 10 traps, corn-ed to 1.5 specimens in the pasture, is unexplained except intns of preference or food supply. Lycosa helluo also was manyles more numerous in the traps in the cultivated field.(Aninteresting anomaly is noted in the occurrence of Par-sa saxatilis s. s. and P. saxatilis "var. atlantica," which usual-are not separated taxonomically. P. saxatilis s. s. was takenlyi the cultivated field; P. saxatilis "var. atlantica" was col-ted in approximately equal numbers in both environments.EIlBLE 1. Comparison of spiders taken per 10 pitfall traps inund stratum of pasture and adjacent cotton field near Mor-on, Arkansas, 1962.CultivatedDictynidae Pasture FieldIDictyna segregata Gertsch & Mulaik 0.0 21lyphiidaeMeioneta micaria (Em.) 0.0 1Mcioneta sp. 0.5 337Journal of the Arkansas Academy of Science, Vol. 17 [1963], Art. 8https://scholarworks.uark.edu/jaas/vol17/iss1/8Arkansas Academy of Science ProceedingsCultivatedFieldPasture1.5Tennesseellum formicum (Em.)Lepthyphantes sp.070.5ErigonidaeErigone autumnalis Em.Eperigone tridentata (Em.)Eperigone aff. tridentata (Em.)Eperigone maculata (Banks)Eperigone sp.1.5 300.0 10.0 220.0 60.5 1Ceraticelus sp.Floricomus sp.3.0 10.0 1Grammonota inornata Em.Walckenaera vigilax (Blackwall)20.5 321.0 6TheridiidaeLatrodectus sp.Theridion sp.0.5 \0.0ArgiopidaePachygnatha tristriata C. L.KochMimognatha foxi (McCook)1.0 \0.5AgelenidaeAgelenopsis sp.Cicurina sp.0.51.536.00.02.04.00.07.0%LycosidaeSchizocosa avida (Walck.)Schizocosa sp.342Arctosa funerea (Hentz)Lycosa rabida Walck.Lycosa punctulata Hentz023Lycosa antelucana MontgomeryLycosa helluo Walck.04.5 96Lycosa helluo "var. annexa Ch. & Ivie'Pardosa saxatilis (Hentz)0.0 130.0 4Pardosa milvina (Hentz) 1.5 472Pardosa pauxilla Montgomery 38.0 24Pardosa saxatilis "var. atlantica Em."Pirata minutus Em.7.0 100.0 3Pirata n. sp. A. 0.0 2Pirata sylvanus Chamb. & IviePirata aff. insularis Em.0.5 220.0 1Pirata sedentarius MontgomeryPirata n. sp. B.0.0 10.5 5OxyopidaeOxyopes salticus Hentz 1.026.000Oxyopes aff. helius Chamb.GnaphosidaeDrassyllus creolus Chamb. & Gertsch 0.0 138Journal of the Arkansas Academy of Science, Vol. 17 [1963], Art. 8Published by Arkansas Academy of Science, 1963Spider FaunaCultivatedPasture FieldDrassyllus mephisto Chamb. 7.0 0Drassyllus aff. fallens Chamb.. 0.0 1Drassyllus sp. 0.5 4Geodrassus sp. 1.0 2Cylphosa sericata (L.Koch) 4.5 0Zelotes laccus (Barrows) 0.0 2lubionidaeMeriola decepta Banks 2.5 16Castianeira descripta (Hentz) 1.0 1Castianeira vulnerea Gertsch 0.5 0Castianeira longipalpus (Hentz) 0.0 2Castianeira sp. 0.5 5Scotinella formica (Banks) 1.5 0Clubiona abbotii L. Koch 0.5 1Clubiona sp. 1.0 12'homisidaeXysticus texanus Banks 1.5 2Xysticus auctificus Keyserling 0.5 0Oxyptila sp. 0.0 1Thanatus sp. 1.0 0alticidaeEris marginatus (Walck.) 0.5 0Habronattus coronatus (Hentz) 5.0 2Habronattus sp. 1.0 2Sitticus floridanus Gertsch &Mulaik 0.0 1Phidippus carolinensis Peck. & Peck. 0.0 1Literature CitedIrnes, Robert D. 1953. The ecological distribution of spiders in non-forest maritime communities at Beaufort, North Carolina. Ecol. Monogr.23: 315-337.Irnes, Robert D., and Betty Martin Barnes. 1955. The spider populationof the abstract broomsedge community of the southeastern Piedmont.Ecology 36 (4): 658-666.»:hter, Edson. 1941. Apparatus for the comparison of soil surface arthro-pod populations. Ecology 22 (3): 338-339.Jnsley, S. D., W. H. Long, L. R. Roddy, W. J. McCormick, and E. J.Concienne. 1961. Effects of insecticides on the predaceous arthropodfauna of Louisiana sugarcane fields. Jour. Econ. Ent. 54 (1): 146-149.twrie, D. C. 1948. The ecological succession of spiders of the Chicagoarea dunes. Ecology 29 (3): 334-351.tima, H., and Katharine E. Muma. 1949. Studies on a population ofpr irie spiders. Ecology 30 (4) : 485-503.fioades, W. C. 1962. A synecological study of the effects of the importedfire ant eradication program. Florida Ent. 45 (4): 161-173.tiith- Davidson, Vera. 1932. The effect of seasonal variability uponanimal species in total populations in a deciduous forest succession. Ecol.Monogr. 2: 306-323.»uman, L. C. 1942. A taxonomic and ecologic study of the spider faunaof Presque Isle. Pittsburgh Univ. Bull. 38 (2): 404-411.Bhitcomb, W. H., Harriet Exline, and Robert Hunter. 1963. Spiders ofthe Arkansas cotton field. Ann. Ent. Soc. America. 56 (5): 653-660.39Journal of the Arkansas Academy of Science, Vol. 17 [1963], Art. 8https://scholarworks.uark.edu/jaas/vol17/iss1/8

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Comparison of Spider Populations of Ground Stratum in Arkansas Pasture and Adjacent Cultivated Field

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