Research Collection
Conference Paper
Ecology of spiders in meadows near Zurich (Switzerland)
Author(s):
Benz, Georg; Nyffeler, Martin Publication Date:
1980
Permanent Link:
https://doi.org/10.3929/ethz-a-005778591
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In Copyright - Non-Commercial Use Permitted
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ETH Library
Arachnologen-Kongreß Wien 1980
SEPARATfIM
121
ECOLOGY OF SPIDERS IN MEADOIVS NEAR ZURICH (SI{ITZERLAND)
c. Benz & 11. IJvffeler
I,ieb-building and hunting spiders can play an important röfe in the biocoenoses of grassland ecosystems concerning den- sity, biomass and energy flow (1), (3) , (4) , (7), (8), (9). Many questions on the ecology of spiders are still open. This study on the ecology of spiders in meadows near Zurich should answer some of these que3tions.
The studies were conducted from I976-1979 in uncultivated and cultivated meadows near Zurich. The species composition of the spiders in the vegetation stratum was determined by sweeping. The species composition and the activity densities
(Aktivitätsdichte) of the epigeic spiders were studied with the help of pitfall traps. The spider's prey spectra were examined through direct field observation. The population densities were measured vrith the method of squares.
Results
Spiders in the vegetation stratum of uncultivated meadows
In the vegetation stratum of uncultivated meadows mainly web spiders of the families Argiopidae, Tetragnathidae, Agelenidae, Theridiidae, Dictynidae, Linyphiidae, Micryphan- tidae as well as hunting spiders of the families Salticidae, Thomisidae, Pisauridae and Clubionidae were found. The
predominant species are fisted in Tab. 1.
Concerning the number of individuals quantitative prey analyses have shown that the food of numerous web spiders living in the vegetation stratum mainly consists of small Diptera, winged aphids etc. (Tab. 2). The prey spectrum of Thomisidae which ambush insects on plants is also largely composed of small Diptera. fn regard to biomass, the food of farge orb web spiders in certain types of uncultivated meadows predmoninantly consists of grasshoppers and/or bees
(s) .
The density of spiders in the vegetation stratum of unculti- vated meadows came to about IO spiders /m2 tn spring/summer r919.
Spiders in the vegetation stratum of cultivated meadows
In the vegetation stratum of cultivated meadows, mostly web
spiders of the families Argiopidae, Tetragnathidae, Theri- diidae and hunting spiders of the family Thomisidae are found. The predominant spider species are listed in Tab. I.
Their prey consists mainly of small Diptera (6).
The density of all spiders in the unmowed vegetation stratum of a cuf tivated meadow !,/as about I . 6 spiders/m2 j-n spring 1979. After mowing, the number of these spiders was
reduced by more than 50?.
TLie pr,.dominant spid.er species, caught vith the sweep net in the !ege- tation stratum of uricultivated and cuftivated neadovs near Zurich in
summer 1979.
Spider family
Spi der spec ie s
Tlrpe of meador^r unculti- culti- vated vate.l
Argi opi dae
Tetragnathidae
Iiicrphant idae Theridii dae
Thoni s id.ae
Salticidae
Pi sauridae
Mangova ct.coL-upha ( l"/atckenaer tB02 )
Species of TabLe 2
fexragnn cha exLensa (Linnaeus lzB) )
ferragnarh t pi,ticoLa l'. Kocn Iö70
Pochggnatha dcgeeri Sundevafl I8J0 HyLgpLnntes nt gritusx (sirnon rBB\) Thert)dt,on oratwn (Clerck 1757)
Theridion bimacuLatum (r,innaeus fTb'f )
Ther"-dion t rtpresstt"rt L. Koch fB81
Xysticus cristatus (Clerck 1757)
Xgstt,ctLs kochi Ihoren IST2
Eoarcha arcu"ata (Clerck 17r?) Heliophanus flaaipes C.L. Koch lB)+B Ptsaura rnTaabL rTs (tIercK 1l)ll
X X X
x) WIEHLE associates this species vith l''licrlThantidae as vefl as vath Linyphiidae (9),(ro).
TABLE 2
Prey cornposition of orb veb spiders (Argiopid-ae and Tetragnatniaae) in an uncultivated meadov near Zurich-Opfikon in summer f979.
Diptera Homoptera HymenoPtera
X X X
X X x
X
x
x
X X
X
x
X
At,giope bv,uennichi ( Scopoli 1772 )
Araneus diad.enatus Clerck f?57 Araneus q,ndratus Clerck 1757
Nucteneax cor'rluta (Clerck 1757 )
Tetz:agnatha er:tensa
53.9 % 59.5 % 7\.r"1 Bt.z %
ß.r %
9.6 %
r2.B %
16.6 %
aad o.)+ %
x Nuctenea Sirnon p Araneus Clerck]
6g.B % 15.3 % 7.9 %
x
123
trpigeic spiders of cultivated rneadows
On the ground of cultivated meadows near Zurich, web spiders of the family Micryphantidae (nrigone atra (Bfackwall 1841), Erigone dentlpaLpt s (l'Jider 1834), 0edothorax fuscus (Black- wall 1834)) and hunting spiders of the familles Lycosidae
(Partlosa agrestis (ln/estring I861), Pdrdosa paLustrt s
(Linnaeus I785), Ttochosa ruricola (Degleer 1778)) and Tetraglnathidae (Pachygnatha degeer r) pred.oninate.
The Micryphantidae mostly feed on Collembola (Sminthuridae), aphids and smafl Diptera. Lycosidae prey also mainly on small soft bodied insects such as Collembofa, aphids etc. (6).
The density of epigeic web spiders in cultivated meadows
near Zurich varied between 15 and 42 spiders/m2 in spr)-ng/
summer 1979. The denslty of hunting spiders has not been determined yet.
The activity density (= number of epigeic spiders/trap/day) was signif icantly lower af ter mowing (Ilann-l'Jhitney U-test, P <0.05).
The epigeic spiders of uncultivated meadows have not been investigated.
Discussion
A comparison of the species composition of spiders in uncuf- tivated and cultivated meadows shows that many spider
species dominant j-n uncultivated meadows also dominate in cultivated meadows (e.9. I'etragnatha extensa, T. ptnicoLa, lhez,idion oratum, T. bimaculatum, Xysttcus crtstatus),
There exist nevertheless great differences between the live systems of uncultivated and cultivated meadows. In the latter the habitat as welf as the eggs of many spiders are periodically destroyed through mowing, whereas the spiders in the uncultivated meadows live undisturbed. Mowing has therefore a negative influence on the spider populations.
This is shown by the following facts:
I - The spider density in the vegetation stratum of unculti- vated meadows is significantly higher than in the vegetation stratum of cultivated meadows.
2 - Hunting spiders of the families Salticidae and Pisauridae are frequentJ-y found in uncultivated meadows, but are almost fulIy missing in cultivated meadows.
3 - Large web spiders (e.9. AgeLena Labyrt,nthtca (C:-erck Il56), At"giope bv,uennichi, Araneus quadratus) are found in uncultivated meadows in relatively high densities, but are rare in cultivated meadows.
4 - The spider density in cultivated meadows becomes signi- ficantly reduced after movring.
Tnvestigations by KAJAK and coworkers in cuftivated meadows
in Poland gave similar density values for the spiders of the vegetation stratum as those reported here, though the
sarne is true for the epigeic spiders, where tl-re Lycosidae dominate in Poland, whereas in Switzerland the 14icryphanti- dae are nore important. Since the latter are not even men- tioned in the Polish papers it is possible that they have not been investiqated. This may explain the lower density of epigeic spiders found in the Polish cultivated meadows ' Concerning the density of the spiders of the vegetation stratum of uncultivated meadows, an about five times lovrer value was found in Zurich than in Poland, where a forest rneadow has been investigated.
Despite these differences the Polish authors have likewise shown that the spider densities in cultivated meadows are signif.icantly lower than in uncultivated meadows ' In addi- tiÄn they observed too, that many spiders in the vegetation stratum of meadows are primarily predators of Diptera (2),
(3), (4). As the density of spiders in cultivated meadows j-s significantly lower than in uncultivated meadows, the un".gy flow through the spider populations of the cultivated meadows is distinctlY lower.
References
(1) EDVIARDS, C.4., C.G. BUTLER and J.R' LOFTY (I976) : The
invertebrate fauna of the park grass plots' II' Sur- face fauna. Rep. Rothanst. exp. Stn. L975, Part 2, 63 - 89.
(2) KAJAK, A. (1965): An analysis of food relations bet- vreen the spiders - Araneus carnututt Cl' and Araneus quad.ratus CL. - and their prey in neadows' trkol'Pol' A 13, 7r7 - 164.
(3) KAJAK, A. (1971): Productlvrty investigation of two types of meadows in the Vistula Valley' TX' Produc- tion and consumption of field layer spiders, Ekol' PoI. A 19, I97 - 2II.
(4) KAJAK, A., A. BREYI'IXYER and J. PETAL (1971): Procluc- tivity investigation of two types of meadows in t'he Vistufa Valley. Xf. Predatory arthropods' Ekol' Pol' n 1o "") _ 2J3.
(5) NYFFELER, l'1. and G. BEIJZ (1978): Prey selection by the web spiders Argiope btuennicht' (Scop.), Araneus
quadnatus C1. and AgeLena Labyrinthlca (CI') on falIow land near Zurich, Switzerland, Rev.suisse Zool' 85' 141 - 157.
(6) IJYFFELER, l{. and G. BErJZ (1919): Overlap of the nichcs concerning space and prey of crab spiders (Arancac:
Thomisidae) and wolf spiders (Araneae: Lycosidae) in cultivated meadows. Rev-suisse zooL. 86, 855 - 865'
125
(7) SCHAEFER, l{. (1.911): Experimental studies on the lmpor- tance of interspecies competition between three woff spider specles (Araneida: Lycosidae) in a salt marsh.
Zool.Jb.Syst. IOI,213 - 235.
(8) TURNBULL, A.L. (1966): A population of spiders and their potentlal prey in an overgrazed pasture in eastern Ontario. Can. J.ZooI. 44, 557 - 583.
(9) VAI{ HOOK, R.I. (1971) : Energy and nutrient dynamics of spider and orthopteran populations in a grassland ecosystem. Ecol.l{onogr. 4It I - 26.
(r0) I'lIEHLtr, H. (1956): Linyphiidae - Baldachinsp.innen. - fn: DAHL, Die Tierwelt Deutschlands, Teil 44.
( f I ) I,VIEHLE, Ii, (r 960) : l4icryphantidae - Zwergspinnen. - In: DAHL, Die Tierwelt Deutschlands, Teil 47.
Addresses:
Prof. Dr. Georg BEI{Z, Department of Entomology, Swiss Federal Institute of Technology, ETH-Zentrum, CII-8092 ZURICH, Switzerland.
Dipl. Inq.-Agr. Martin lJyffefer (same address).
