TUGAS UAS EKOLOGI HEWAN

Disusun oleh :

M. NASRULAH AKBAR 140410120087

DEPARTEMEN BIOLOGI

FAKULTAS MATEMATIKA DAN ILMU PENGETAHUAN ALAM

UNIVERSITAS PADJADJARAN

JATINANGOR

2014

Eur. J. Entomol. 107: 277–280, 2010

http://www.eje.cz/scripts/viewabstract.php?abstract=1536

ISSN 1210-5759 (print), 1802-8829 (online)

Pengaruh Warna Dari Pitfall Trap terhadap Efisiensi Penangkapan

Kumbang Carabid (Coleoptera: Carabidae), Laba-Laba (Araneae), dan

Arthropoda Lainnya

SASCHA BUCHHOLZ1, ANNA-MARIE JESS1, FLORIAN HERTENSTEIN1, and JENS SCHIRMEL2

1Department of Community Ecology, Institute of Landscape Ecology, University of Münster,

Robert-Koch-Straße 26, 48149 Münster, Germany; e-mails: saschabuchholz@uni-muenster.de,

annajess@gmx.de, flohertenstein@googlemail.com 2Biological Station Isle of Hiddensee,

University of Greifswald, Biologenweg 15, 18565 Hiddensee, Germany; e-mail:

jens_schirmel@web.de

Abstrak

Pitfall trap merupakan salah satu metode yang paling umum digunakan dalam

pengambilan sampel serangga yang hidup di tanah. Ada banyak studi tentang

pengaruh desain pitfall trap pada efisiensi penangkapan yang dilakukan,

tetapi, sejauh ini, tidak ada penelitian tentang pengaruh warna pada

pitfall trap. Dalam penelitian ini, kelimpahan dari tujuh kelompok

invertebrata (Apidae, Araneae, Carabidae, Diptera, Formicidae, Isopoda,

Vespinae) tertangkap dalam pitfall trap yang memiliki warna yang berbeda-

beda (putih, kuning, hijau, coklat) di lokasi padang rumput padat dan

kering di Northwestern Jerman yang telah ditentukan. Pada pitfall trap

berwarna putih dan kuning memiliki jumlah terbanyak dalam penangkapan jenis

Apidae, Araneae, Carabidae, Diptera, dan Formicidae. Sedangkan, jenis

Isopoda melimpah pada pitfall trap berwarna hijau dan cokelat. Perbedaan

jumlah tangkapan yang signifikan terdapat pada jenis Apidae, Araneae,

Carabidae dan Diptera. Pengaruh warna pada hasil tangkapan tidak berbeda

secara signifikan pada setiap lokasi pengambilan sampel. Pengetahuan

tentang variasi dalam efisiensi penangkapan pada pitfall trap dengan warna

yang berbeda sangat penting untuk merancang survei terhadap invertebrata,

baik dari sudut pandang ilmiah dan etika.

Kata kunci: Keselamatan hewan, Araneae, penangkapan, Carabidae, efisiensi

penangkapan, pitfall trap, desain pengambilan sampel

PENDAHULUAN

Pitfall trap pertama kali dijelaskan oleh Barber (1931) adalah metode

yang sangat sering digunakan untuk pengambilan sampel pada ekologi

terestrial (New, 1998). Meskipun demikian, banyak sanggahan (misalnya

Bombosch, 1962; Halsall & Wratten, 1988; Lang, 2000; Topping & Sunderland,

1992; topping, 1993) yang menyatakan bahwa pitfall trap yang cocok untuk

mengetahui frekuensi dan kelimpahan relatif arthropoda tanah seperti

kumbang Carabid (Coleoptera: Carabidae) dan laba-laba (Araneae) (Adis,

1979; Luff, 1975; Müller, 1984; Tretzel, 1955; Uetz & Unzicker, 1976).

Umumnya, pitfall trap terdiri dari wadah yang tertanam rata dengan

permukaan tanah dan diisi dengan cairan yang dapat mengawetkan dan membunuh

hewan apapun yang jatuh ke dalam perangkap (Balogh, 1958; Barber, 1931;

Grell, 1997). Keuntungan dari metode ini adalah dapat menghemat waktu,

mudah digunakan, murah, dan hasil tangkapannya kaya akan spesies ataupun

individu yang didapatkan (Spence & Niemela, 1994).

Sudah banyak studi yang telah melakukan penelitian tentang pengaruh

perbedaan desain atau bentuk pitfall trap pada efisiensi penangkapan

serangga (Misalnya Borgelt & New, 2005;. Brennan et al, 1999; Buchholz &

Hannig, 2009; Curtis, 1980; Digweed et al., 1995; Jud & Schmidt-Entling,

2008; Pekar, 2002; Santos et al., 2007; Schmidt et al., 2006; Waage, 1985;

Ward et al., 2001). Namun, pengaruh perbedaan warna pitfall trap terhadap

efisiensi penangkapan invertebrata belum pernah diteliti. Dalam beberapa

penelitan sering menggunakan warna gelas plastik berwarna putih pada metode

pitfall trap (misalnya Finch et al, 2007;. Sroka & Finch, 2006) dan pada

penelitian lainnya menggunakan stoples kaca (transparan) (misalnya Lovei et

al, 2006; Magura et al, 2001; Negro et al, 2009.; Sadler et al., 2006).

Warna dari pitfall trap bisa menjadi penting dalam konteks melindungi

spesies, keselamatan hewan, dan pertimbangan dalam sudut pandang etika

dalam ilmu pengetahuan, karena sangat penting untuk mengurangi tangkapan

yang tidak disengaja (Putman, 1995; New, 1999). Karena pitfall trafo

merupakan metode non-selektif terhadap pengambilan sampel sehingga biasanya

banyak organisme yang berbeda-beda –yang sebenarnya tidak diinginkan- ikut

tertangkap (kadang dalam jumlah yang sangat banyak). Pitfall trap berwarna

putih (misalnya berbagai jenis toples plastik) digunakan untuk menangkap

Diptera (misalnya Syrphidae) dan Hymenoptera (misalnya lebah), yang

tertarik pada warna cerah dan warna mencolok (Kirk, 1984; Kratochwil, 1984;

Ssymank, 1991). Namun, seringkali organisme yang tertangkap bukan subjek

penelitian sehingga data tidak dapat dianalisis secara statistik karena

ketidaksesuaian pada pitfall trap sebagai metode sampling untuk spesies ini

(Bombosch, 1962; Buchholz et al., 2008). Pengetahuan tentang bagaimana

desain pitfall trap yang mempengaruhi efisiensi penangkapan dan komposisi

spesies invertebrata yang tertangkap sangat penting untuk dikaji tidak

hanya dari segi ilmiah, tetapi juga dari sudut pandang etika (New, 1999;

Ward et al, 2001).

Tujuan dari penelitian ini adalah untuk membandingkan efisiensi

penangkapan arthropoda dari perbedaan warna perangkap. Kami menggunakan

warna coklat dan hijau yang mencolok serta warna putih dan kuning terang

untuk menyelidiki kemungkinan adanya perbedaan penangkapan. Pertanyaan

penelitian berikut yang dibahas, antara lain: (i) Apakah warna pada pitfall

trap yang berbeda mempengaruhi perbedaan dalam efisiensi penangkapannya?

Jenis arthropoda mana yang terpengaruh? (ii) Dapatkah warna pitfall trap

yang tepat dapat mengurangi adanya tangkapan “sampingan” ketika pitfall

trap yang digunakan untuk studi arthropoda yang tinggal di tanah (terutama

kumbang Carabidae dan laba-laba)?

BAHAN DAN METODE

Wilayah studi dan desain pengambilan sampel penelitian ini dilakukan

di dekat kota Münster (51 ° 57'46.6˝N, 7 ° 37'43.3˝E) Rhine-Westphalia,

Jerman Utara. Iklim di daerah ini adalah sub-oceanic dengan suhu rata-rata

tahunan 7,9°C dan curah hujan tahunan 758 mm (Kementerian Lingkungan Hidup,

Tata Ruang dan Pertanian dari NRW, 1989). Dua lokasi dengan vegetasi

homogen struktur yang dipilih, antara lain: padang rumput kering jarang

bervegetasi (Corynephoretum, cakupan tanaman herba [CH] = 20%, tinggi

tanaman herba [HH] = 15 cm) dan vegetasi padat, situs padang rumput (Lolio-

Cynosuretum; CH = 100%, HH = 50-60 cm).

Pada dua lokasi dibuat 60 lubang perangkap berwarna (tabung plastik,

diameter = 9 cm, tinggi = 12 cm) yang diisi dengan 3% larutan formalin dan

deterjen. Perangkap yang digunakan berwarna coklat, hijau, putih, dan

kuning yang disusun dalam pola dengan jarak antar perangkap 5 meter. Pada

lokasi padang rumput kering 16 pitfall trap (4 perangkap tiap warna) yang

ditetapkan dan pada padat vegetasi Situs padang rumput 44 pitfall trap (11

perangkap tiap warna) (Gambar 1). Perangkap ini digunakan untuk menangkap

arthropoda dari 24 April - 6 Juni 2009 dan dikosongkan sekali dua minggu.

Gambar 1. Tata letak pitfall trap yang berbeda warna di situs padang rumput kering (16 perangkap, 4 baris

dan 4 kolom) dan Situs padang rumput (44 perangkap, 11 baris dan 4 kolom). b - coklat, g - hijau, w - putih

dan y - kuning.

ANALISA

Setelah dilakukan pengosongan pada tiap pitfall trap, arthropoda yang

didapat diurutkan dan diawetkan menggunakan etil alkohol. Arthropoda yang

ditemukan secara berturut-turut, yaitu Araneae, Carabidae, Diptera,

Formicidae, Apidae, Vespinae dan Isopoda. Individu yang tertangkap

digunakan untuk analisis jumlah. Untuk menilai apakah ada perbedaan yang

signifikan dalam efisiensi penangkapan di antara empat warna pitfall trap

yang berbeda (coklat, hijau, putih, kuning) kami menggunakan model linier

umum (General Linier Models) dan termasuk "situs" (padang rumput kering,

padang rumput) sebagai prediktor kedua. Semua uji statistik dilakukan pada

software R versi 2.9.0.

HASIL

Pada seluruh pitfall trap didapatkan 6.436 Araneae, 1.122 Carabidae,

603 Diptera, 3.689 Formicidae, 50 Apidae, 92 Vespinae, dan 5.069 Isopoda

(total = 17.061). Secara keseluruhan hasil tangkapan menurun dari tiap

warna pitfall trap putih> kuning> hijau> coklat, namun, perbedaan jumlah

tangkapan tiap pitfall trap yang berbeda warna tidak signifikan (P = 0,10;

Tabel 1).

Perbedaan antara angka tertangkap yang signifikan untuk Apidae (P

<0,001), Araneae (P <0,001), Carabidae (P <0,01) dan Diptera (P <0,001).

Lebih dari taksa tersebut tertangkap dalam perangkap putih diikuti oleh

perangkap kuning. Tidak ada perbedaan yang signifikan dalam jumlah

Formicidae (P = 0,08), Isopoda (P = 0,20) dan Vespinae (P = 0.61) yang

tertangkap oleh pitfall trap dengan warna yang berbeda. Pengaruh warna pada

hasil tangkapan tidak berbeda secara signifikan antara tiap lokasi.

TABEL 1. jumlah  individu standar (individu rata-rata per hari ± SD) yang terjebak dalam

pitfall trap berwarna yang berbeda (perwarna n = 15).

PEMBAHASAN

Hasil penelitian kami menunjukkan bahwa pada padang rumput terbuka,

arthropoda yang tertangkap pada lubang pitfall trap adalah kumbang

Carabidae dan laba-laba (misalnya Kratochwil & Schwabe, 2001; Lambeets et

al, 2008, 2009; Negro et al., 2009), yang paling sering tertangkap pada

pitfall trap berwarna putih dan berwarna kuning perangkap. Dengan demikian,

kumbang Carabid dan laba-laba di habitat terbuka tampaknya tertarik dengan

warna-warna cerah, mungkin karena perbedaan kontras yang tajam antara

perangkap dan sekitarnya (vegetasi / tanah) dan antara perangkap dan

mungkin mangsa (ditunjukkan untuk Cicindelidae oleh Faasch, 1968; Gebert,

1991). Hal ini sesuai dengan penelitian Van der Drift (1951) bahwa para

Carabid Notiophilus adalah pemburu visual dan penelitian Foelix (1992) yang

mengemukakan bahwa laba-laba berburu seperti Thomisidae, Salticidae dan

Lycosidae telah berkembang dengan baik kemampuan untuk melihat, yang dapat

memungkinkan spesies ini untuk melihat warna atau warna yang kontras.

Seperti yang diharapkan, hasil tangkapan arthropoda bersayap seperti

Diptera dan Apidae tertangkap lebih besar dalam perangkap putih dan kuning,

yang merupakan warna bunga secara umum (Kirk, 1984; Muhlenberg, 1993).

Sebaliknya hasil tangkapan dari Vespinae tidak terpengaruh oleh perangkap

warna. Spesies ini merupakan penyerbuk yang tidak khas dan oleh karena itu

kemungkinan besar tidak akan tertarik dengan warna-warna bunga. Demikian

pula warna lubang perangkap tidak mempengaruhi hasil tangkapan dari

Isopoda. Hasil tangkapan yang tinggi dari Isopoda dalam perangkap berwarna

gelap bisa dijelaskan oleh fakta bahwa sebagian kutu kayu mencari tempat

penampungan gelap untuk menghindari cahaya dan kering pada lokasi (Abbott,

1918; Sutton, 1980; Sutton & Holdich, 1984). Formicidae juga tidak

menunjukkan adanya tanggapan terhadap warna perangkap. Hal ini disebabkan

terjadinya kerumunan semut dekat sarang dan jalan mereka mungkin memiliki

yang pengaruh yang kuat pada jumlah individu yang tertangkap oleh perangkap

(Laeger & Schultz, 2005; Seifert, 1990). Dalam konteks ini, kita harus

mengingat masalah umum terkait dengan penggunaan pitfall trap sebagai

metode sensus untuk semut (Agosti et al, 2000;. Majer, 1997;. Schlick-

Steiner et al, 2006; Steiner et al., 2005).

Kesimpulannya, jika tujuannya adalah untuk meningkatkan efisiensi

penangkapan kumbang Carabid dan laba-laba maka penggunaan pitfall trap

berwarna putih yang dianjurkan. Dalam kebanyakan studi besar jumlah

individu menghasilkan tingkat ketelitian yang tinggi dan kelengkapan

keberadaan spesies (misalnya Brose, 2002; Brose et al., 2003; Cardoso et

al., 2008; Perner, 2003; Shen et al., 2003). Namun demikian, bila

menggunakan pitfall trap coleopterologists dan arachnologists berwarna

putih (atau kuning) harus disadari bahwa tidak dapat dihindari bahwa akan

ada sejumlah besar tangkapan “sampingan” yang paling tidak merupakan

individu Apidae dan Diptera. Oleh karena itu, ketika menggunakan perangkap

seperti itu, sangat disarankan bahwa semua tangkapan “sampingan” dianalisis

seperti yang disarankan oleh Buchholz et al. (2008), misalnya, dengan

bertukar infora tangkapan “sampingan” dengan para ahli lainnya.

UCAPAN TERIMA KASIH. Kami ingin mengucapkan terima kasih kepada K.

Mantel yang telah membantu kerja lapangan dan J. Schalajda dan dua anonim

sebagai pengulas untuk komentar pada versi naskah sebelumnya. Kami

berterima kasih kepada R. Baumgartner untuk meningkatkan pemakaian bahasa

Inggris.

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UETZ G.W. & UNZICKER J.D. 1976: Pitfall trapping in ecological studies of

wandering spiders. J. Arachnol. 3: 101–111.

VAN DER DRIFT J. 1951: Analysis of the animal community in a beech forest

floor. Tijdschr. Entomol. 94: 1–168.

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plastic pitfall traps containing different solutions. Fauna Nor. (B)

32: 33–36.

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abundance, richness and composition of invertebrata catches. J. Insect

Conserv. 5: 47–53.

Received December 17, 2009; revised and accepted February 8, 2010

NOTE

Eur. J. Entomol. 107: 277–280, 2010

http://www.eje.cz/scripts/viewabstract.php?abstract=1536

ISSN 1210-5759 (print),1802-8829 (online)

Effect of the colour of pitfall traps on their capture efficiency of carabid beetles

(Coleoptera: Carabidae), spiders (Araneae) and other arthropods

SASCHA BUCHHOLZ1, ANNA-MARIE JESS1, FLORIAN HERTENSTEIN1 and JENS SCHIRMEL2

1Department of Community Ecology, Institute of Landscape Ecology, University of Münster, Robert-Koch-Straße 26,

48149 Münster, Germany; e-mails: saschabuchholz@uni-muenster.de, annajess@gmx.de, flohertenstein@googlemail.com2Biological Station Isle of Hiddensee, University of Greifswald, Biologenweg 15, 18565 Hiddensee, Germany;

e-mail: jens_schirmel@web.de

Key words. Animal welfare, Araneae, by-catch, Carabidae, capture efficiency, pitfall trapping, sampling design

Abstract. Pitfall trapping is one of the most commonly used methods of sampling ground-dwelling arthropods. There are manystudies on the effect of design of pitfall traps on their capture efficiency but, so far, none on the influence of the colour of the pitfalltrap. In this study the abundances of seven invertebrate groups (Apidae, Araneae, Carabidae, Diptera, Formicidae, Isopoda,Vespinae) caught in pitfall traps of different colours (white, yellow, green, brown) at a dense and dry grassland site in NorthwesternGermany were determined. White and yellow pitfall traps caught by far the highest numbers of individuals of Apidae, Araneae,Carabidae, Diptera and Formicidae. Isopoda were most abundant in the catches of green and brown traps. Differences among num-bers caught were significant for Apidae, Araneae, Carabidae and Diptera. The effect of colour on the catches did not differ signifi-cantly between sites. Knowledge of the variation in the catching efficiency of differently coloured pitfall traps is important fordesigning invertebrate surveys, both from a scientific and ethical point of view.

INTRODUCTIONPitfall traps, first described by Barber (1931), are a very fre-

quently used for sampling in terrestrial ecology (New, 1998).Despite criticisms (e.g. Bombosch, 1962; Halsall & Wratten,

1988; Lang, 2000; Topping & Sunderland, 1992; Topping,1993), pitfall traps are suitable for studying the occurrence andrelative abundance of ground-dwelling arthropods such ascarabid beetles (Coleoptera: Carabidae) and spiders (Araneae)(Adis, 1979; Luff, 1975; Müller,

1984; Tretzel, 1955; Uetz &Unzicker, 1976). Generally, pitfall traps consist of containersthat are embedded flush with the ground surface and filled witha liquid that both preserves and kills any animals falling into thetraps (Balogh, 1958; Barber, 1931; Grell, 1997). This self-sampling method is time-efficient, easy to use, inexpensive andresults in catches rich in both species and individuals (Spence &Niemelä, 1994).In many studies the effect of different pitfall designs (e.g.

size, diameter, fluid type, spacing,trap type) on the capture effi-ciency has been analysed (Borgelt & New, 2005; Brennan et al.,1999; Buchholz & Hannig, 2009; Curtis, 1980; Digweed et al.,1995; Jud & Schmidt-Entling, 2008; Pekár, 2002; Santos et al.,2007; Schmidt et al., 2006; Waage, 1985; Ward et al., 2001).However, the effect of pitfall trap colour on the efficiency withwhich invertebrates are caught by these traps has not been stud-ied. In some studies plastic cups (often white coloured) wereused (e.g. Finch et al., 2007; Sroka& Finch, 2006) in othersglass jars (transparent) (e.g. Löveiet al., 2006; Magura et al.,2001; Negro et al., 2009; Sadler et al., 2006). The colour of apitfall trap could be important in the context of species protec-tion, animal welfare and ethical considerations in science, as itis important to reduce unintentionalby-catches (Putman, 1995;New, 1999). Pitfall traps are a non-selective sampling methodand normally catch many different organisms (sometimes inhigh numbers). When white coloured traps (e.g. many kinds ofplastic jars) are used mainly flower-seeking Diptera (e.g. Syr-phidae) and Hymenoptera (e.g. bees),which are attracted to

bright, striking colours (Kirk, 1984; Kratochwil, 1984;Ssymank, 1991), are caught. Often, these by-caught organismsare not the subject of the study and are not determined or thedata can not be analysed statistically because of the unsuitabilityof pitfall trapping as a sampling method for these species (Bom-bosch, 1962; Buchholz et al., 2008). A knowledge of how thedesign of a pitfall trap affects its catchingefficiency and thespecies composition of the invertebrates it catches is importantnot only from a scientific but also from an ethical point of view(cf. New, 1999; Ward et al., 2001). The aim of this study is tocompare the capture efficiency of arthropods of differently col-oured traps. We used the inconspicuous and earthy coloursbrown and green and attractive colours white and yellow toinvestigate possible differences. The following research ques-tions were addressed: (i) Do different coloured pitfall trapsdiffer in their capture efficiency? Which arthropods areaffected? (ii) Can the right choice of colourreduce the incidenceof by-catches when pitfall traps are used forstudying ground-dwelling arthropods (mainly carabid beetles and spiders)?

MATERIAL AND METHODS

Study area and sampling designThis study was performed near the city of Münster

(51°57´46.6˝N, 7°37´43.3˝E) North Rhine-Westphalia Germany.The climate in this region is sub-oceanic with mean annual tem-perature of 7.9°C and annual precipitation of758 mm (MURL,the Ministry for the Environment, Spatial Planning and Agricul-ture of NRW, 1989). Two sites with homogeneous vegetationstructure were selected: a sparsely vegetateddry grassland(Corynephoretum; coverage of herbaceous plants [CH] = 20%,height of herbaceous plants [HH] = 15 cm) anda densely vege-tated grassland site (Lolio-Cynosuretum; CH =100%, HH =50–60 cm).At the two sites a total of 60 coloured pitfall traps (plastic jar,

diameter = 9 cm, height = 12 cm) filled with a 3% formalinsolution and detergent were set. Traps were either brown, green,

277

There were no significant differences in the numbers of For-

micidae (P = 0.08), Isopoda (P = 0.20) and Vespinae (P = 0.61)caught by the different coloured traps. The effect of colouronthe catches did not differ significantly between sites.

DISCUSSION

Our results indicate that in open grassland habitats the most

common arthropods of conservation interest that are caught bypitfall traps, carabid beetles and spiders (e.g. Kratochwil &Schwabe, 2001; Lambeets et al., 2008, 2009; Negro et al.,2009), were most frequently caught in white and yellow col-oured traps. Thus, carabid beetles and spiders in open habitatsseem to be attracted by bright colours, maybe due to the sharpcontrast between the trap and surrounding vegetation/groundand between the trap and possible prey (shown for Cicindelidaeby Faasch, 1968; Gebert, 1991). This accords with both Van derDrift’s (1951) observation that the carabid Notiophilus is a

Fig. 1. Arrangement of the differently coloured pitfall traps at

the dry grassland site (16 traps, 4 rows and 4 columns) andgrassland site (44 traps, 11 rows and 4 columns). b– brown,g – green, w – white and y – yellow.

white or yellow and arranged in a grid in rotational order (dis-tance between traps = 5 m). At the dry grassland site 16 pitfalltraps (4 traps per colour) were set and at the densely vegetatedgrassland site 44 (11 traps per colour) (Fig. 1). These traps wereused to catch arthropods from 24 April to 6 June 2009 and emp-tied fortnightly.AnalysisAfter each emptying, arthropods were sorted and preserved in

ethyl alcohol. Arthropods were determined as Araneae,Carabidae, Diptera, Formicidae, Apidae, Vespinae and Isopoda.For the analysis the numbers of individuals caught were used.To assess whether there were significant differences in captureefficiency between the four pitfall colours (explaining variables:brown, green, white, yellow) we used generalized linear models(GLM) and included “site” (dry grassland, grassland) as asecond predictor. All statistics were performed in R 2.9.0.

RESULTS

Altogether, pitfall trapping yielded 6,436 Araneae, 1,122

Carabidae, 603 Diptera, 3,689 Formicidae, 50 Apidae, 92 Ves-pinae and 5,069 Isopoda (overall catch = 17,061).

Overall catches decreased from white > yellow >green >

brown, however, differences were not significant(P = 0.10;Table 1). Differences among numbers caught were significantfor Apidae (P < 0.001), Araneae (P < 0.001), Carabidae (P <0.01) and Diptera (P < 0.001). More of these taxa were caughtin white traps followed by yellow traps.

visual hunter and Foelix’s (1992) that hunting spiders like theThomisidae, Salticidae and Lycosidae have a well developedability to see, which may allow these species to perceive coloursor contrasts in colour.As expected, the catches of winged arthropods such as Dip-

tera and Apidae were greater in white and yellow traps, whichare common flower colours (cf. Kirk, 1984; Mühlenberg, 1993).In contrast the catches of Vespinae were not affected by trapcolour. Species of this taxon are not typical pollinators andtherefore less likely to be attracted by flower colours. Similarlythe colour of the pitfall traps did not affect the catches of Iso-poda. The high catch of Isopoda in the dark coloured traps canbe explained by the fact that most woodlice seek dark shelters inorder to avoid light and dry sites (Abbott, 1918; Sutton, 1980;Sutton & Holdich, 1984). The Formicidae also showed no clearresponse to the pitfall colour: the clustered occurrence of antsnear their nests and roads might have had a strong affect on thenumbers caught by the traps (Laeger & Schultz, 2005; Seifert,1990). In this context, one has to keep in mind the general prob-

lems associated with using pitfall traps as census method forants (cf. Agosti et al., 2000; Majer, 1997; Schlick-Steiner et al.,2006; Steiner et al., 2005).In conclusion, if the objective is to increase the captureeffi-

ciency of carabid beetles and spiders then the use of white col-oured pitfall traps is recommended. In most studies largenumbers of individuals result in higher levels of precision andcompleteness of species inventories (e.g. Brose, 2002; Broseetal., 2003; Cardoso et al., 2008; Perner, 2003; Shen et al., 2003).Nevertheless, when using white (or yellow) pitfall traps coleop-terologists and arachnologists should be aware that it is inevi-table that there will be large numbers of by-catches of mosttaxa(e.g. Apidae, Diptera). Hence, when utilizing such traps it isstrongly recommended that all the by-catches are analysed as

TABLE 1. Standardized individual numbers (mean individuals per day ± SD) caught in the different coloured pitfall traps (per

colour n = 15).

brownPitfall trap colour

green white yellow Fcolour Fsite Fcolour × site

Overall catchApidaeAraneaeCarabidaeDipteraFormicidaeIsopodaVespinae

217.3 ± 43.50.3 ± 0.268.1 ± 9.915.5 ± 2.17.6 ± 1.536.1 ± 9.288.5 ± 31.31.2 ± 0.5

266.1 ± 47.90.3 ± 0.286.4 ± 11.814.7 ± 2.66.0 ± 1.243.1 ± 12.3114.6 ± 30.30.9 ± 0.2

328.5 ± 45.62.0 ± 0.9

155.8 ± 22.826.8 ± 4.514.3 ± 1.568.3 ± 22.659.6 ± 13.51.8 ± 0.9

307.6 ± 59.10.5 ± 0.3

113.7 ± 16.617.0 ± 3.38.9 ± 1.193.7 ± 33.372.6 ± 20.21.1 ± 0.4

2.2012.85***20.134.22**7.33***2.351.60.62

72.97**122.42***159.24***2.86***2.6512.66***37.90***0.24

0.501.100.220.682.350.290.012.59

278

suggested by Buchholz et al. (2008), for example, byexchanging the by-catches with other experts.

ACKNOWLEDGEMENTS. We would like to thank K. Mantelfor help with the fieldwork and J. Schalajda and two anonymousreviewers for comments on an earlier version of themanuscript.We are grateful to R. Baumgartner for improving theEnglish.

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