Corresponding author: Ivan H. Tuf (
Academic editor: Karel Tajovský
Some species of centipedes and millipedes inhabit upper soil layers exclusively and are not recorded by pitfall trapping. Because of their sensitivity to soil conditions, they can be sampled quantitatively for evaluation of soil conditions. Soil samples are heavy to transport and their processing is time consuming, and such sampling leads to disturbance of the soil surface which land-owners do not like. We evaluated the use of hay-bait traps to sample soil dwelling millipedes and centipedes. The effectiveness of this method was found to be similar to the effectiveness of soil sampling. Hay-bait traps installed for 8–10 weeks can substitute for direct soil sampling in ecological and inventory studies.
Tuf IH, Chmelík V, Dobroruka I, Hábová L, Hudcová P, Šipoš J, Stašiov S (2015) Hay-bait traps are a useful tool for sampling of soil dwelling millipedes and centipedes. In: Tuf IH, Tajovský K (Eds) Proceedings of the 16th International Congress of Myriapodology, Olomouc, Czech Republic. ZooKeys 510: 197–207. doi:
Soil macrofauna is commonly used for monitoring or evaluation of sites. Besides ground beetles (e.g.
The research was done at three sites in the Czech Republic from May to July 2013. The first site was an alfalfa field (
The second site was an old meadow (
In the Czech Republic generally, the weather conditions during the study period were characterised by average or slightly increased temperatures and higher than average precipitation in May-June, and a very hot July in contrast to long-term average values. The previous winter season was rather warmer and with higher precipitation (ref. historical territorial data at
Soil macrofauna, including millipedes and centipedes, was sampled using three methods at each site. Pitfall traps (10 traps consisting of glass jars with inserted plastic pots of diameter 7.5 cm filled with 2 dl of 4% formaldehyde in water with some detergent, metal covers) were arranged in 2 lines of 5 traps with a span of 10 m, and inspected at 2-week intervals. Five soil samples (25 × 25 × 10 cm including litter layer) were obtained using a spatula, three times per study (i.e. 15 soil samples per site) and transported to the laboratory in plastic bags. Hay-bait traps were made from a wire gauze (2 cm mesh) shaped as a simple pocket of size 25 × 25 cm. Each pocket was marked by a code written on the band. These pockets were filled with hay (commercial hay mixture for feeding rodent pets) and submerged into water for 2 hours before installation. Altogether, 60 hay-bait traps were placed horizontally at each site in a following scheme: 5 lines of 12 traps (2-5 cm under soil surface) over a length of 2 m with 10 m between lines. All traps were installed at the same time and 5 traps were taken away each week during the course of the study lasting for 12 weeks. Hay-traps were transported into the laboratory inside separate plastic bags.
Soil samples and hay-traps were heat-extracted immediately in the laboratory using simple Kempson devices (
We tested the effects of trapping time and methods on species richness by repeated-measures on traps with nested design. The traps were nested in each of the three study sites (field, meadow, forest). Explanatory variables in the model were trapping time and trapping methods. The response variable was defined as a number of species per trap for particular time and place. Habitat type was used as random variable. We used a mixed model to estimate the correct error term and degrees of freedom. To test this effect, a generalized linear mixed model (glmmPQL, part of R package MASS) was used with negative binomial error distribution and log link function (
To test if one level of a particular factor (trapping method and study site) is more variable than other levels of the same factor, a permutation test was used (permutest.betadisper, part of R package vegan). This permutation based method tests pairwise comparisons of group mean dispersions. It is based on the t-statistic computed on pairwise group dispersions. A distance matrix was computed based on “Bray-Curtis” index of dissimilarity (vegdist, part of R package vegan). Then the function “betadisper” (part of vegan package in R) was used to calculate variance for each group of samples. Variance was computed as average distance of group members to the group centroid.
Rarefaction curves were constructed to show how the species richness varies for the same sample size between the three trapping methods. Function “rarefy” (part of vegan package in R software) computed the expected species richness and standard deviation in random subsamples of a particular sample size from the community. Data were analysed using R software (
Altogether, we obtained 541 millipedes from 17 species and 435 centipedes from 13 species (Table
List of millipedes obtained using three methods from three biotopes (ind./10 pitfall traps/12 weeks, ind./60 bait traps and ind./0.94m2 respectively.
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- | 9 | 1 | - | - | 1 | - | - | - | 10 | 1 | 0 | |
- | 2 | - | - | 31 | 1 | - | 2 | - | 2 | 32 | 2 | |
2 | - | - | 5 | - | - | - | - | - | 2 | 5 | 0 | |
- | - | 3 | - | - | - | - | - | - | 3 | 0 | 0 | |
1 | - | - | - | - | - | - | - | - | 1 | 0 | 0 | |
- | - | 64 | - | - | 32 | - | - | 4 | 64 | 32 | 4 | |
- | - | - | - | - | 1 | - | - | - | 0 | 1 | 0 | |
- | - | 2 | - | - | 1 | - | - | - | 2 | 1 | 0 | |
- | - | 2 | - | - | 2 | - | - | - | 2 | 2 | 0 | |
- | - | 10 | - | - | 11 | - | - | 4 | 10 | 11 | 4 | |
27 | - | - | 59 | - | - | 2 | - | - | 27 | 59 | 2 | |
- | 9 | 36 | - | 30 | 26 | - | 3 | 2 | 45 | 56 | 5 | |
- | - | - | - | - | - | - | 3 | - | 0 | 0 | 3 | |
- | 3 | 1 | - | 2 | 3 | - | - | 1 | 4 | 5 | 1 | |
- | 8 | - | - | 7 | - | - | - | - | 8 | 7 | 0 | |
- | 1 | - | - | 39 | - | - | 6 | - | 1 | 39 | 6 | |
- | - | 47 | - | - | 26 | - | - | 9 | 47 | 26 | 9 | |
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30 | 32 | 166 | 64 | 109 | 104 | 2 | 14 | 20 | 228 | 277 | 36 |
- | - | 2 | 1 | - | 9 | - | - | - | 2 | 10 | 0 | |
- | - | - | - | - | - | - | 9 | - | 0 | 0 | 9 | |
- | - | 10 | - | 9 | 20 | 1 | 30 | - | 10 | 29 | 31 | |
- | - | - | - | - | - | - | 1 | - | 0 | 0 | 1 | |
- | - | 23 | - | 11 | 60 | - | 26 | - | 23 | 71 | 26 | |
- | - | 4 | - | - | 2 | - | - | - | 4 | 2 | 0 | |
- | - | 41 | - | - | 39 | - | - | - | 41 | 39 | 0 | |
- | - | - | - | - | 2 | - | - | - | 0 | 2 | 0 | |
- | - | 2 | - | - | 1 | - | - | - | 2 | 1 | 0 | |
- | - | 1 | - | - | - | - | - | - | 1 | 0 | 0 | |
- | - | - | - | - | 1 | - | - | 1 | 0 | 1 | 1 | |
- | 4 | - | - | 47 | - | - | 31 | - | 4 | 47 | 31 | |
- | - | 3 | - | - | 3 | - | - | 1 | 3 | 3 | 1 | |
- | - | 14 | 2 | - | 24 | - | - | - | 14 | 26 | 0 | |
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0 | 4 | 100 | 3 | 67 | 161 | 1 | 97 | 2 | 104 | 231 | 100 |
Methods at individual sites were evaluated according to their efficiency using rarefactions (Fig.
Rarefactions of estimated species richness (i.e. number of species) in increasing size of random samples (i.e. number of individuals), comparison of effectiveness of sampling by individual methods at different sites. Vertical lines represent standard errors.
Differences between species lists at all sites and lists sampled by individual methods were compared by pairwise comparisons and differences confirmed between all pairs of sites (Table
Pairwise comparisons of species lists collected (a) at different sites and (b) by different methods. (Observed p-value below diagonal, permuted p-value above diagonal).
a) | field | forest | meadow | b) | hay-bait | pitfall | soil |
field | - | 0.001 | 0.048 | hay-bait | - | 0.003 | 0.917 |
forest | 0.000 | - | 0.001 | pitfall | 0.003 | - | 0.043 |
meadow | 0.041 | 0.004 | - | soil | 0.911 | 0.052 | - |
Evaluation of colonization of hay-bait traps (Fig.
Changes in myriapod communities inside hay-bait traps installed in three biotopes during the 12 week trapping period. Qualitative as well as quantitative parameters are shown for these communities. Open dots are observed parameters, whereas solid lines represent models of succession including standard errors (green shading).
Centipedes and millipedes live on the soil surface and inside soil. We can find them through the whole soil gradient to a depth of one meter (e.g.
Bait traps were used for sampling invertebrates, mainly beetles, in caves originally (
The first documented version of bait traps for millipedes was a shingle trap by
If we are interested in using hay-bait traps as an adequate (or even better) substitute for soil sampling, we have to compare species lists of millipedes and centipedes trapped by these methods. There were only three species recorded exclusively from soil sampling, i.e. missing in hay-bait traps: millipede
One millipede species,
Centipedes, and especially millipedes, are attracted into the hay-bait traps. The possible reason can be as a food source and/or sustainable shelter with higher humidity. At least for millipedes, food source seems to be the more probable explanation; wet cloth method (offering higher humidity) did not record any millipedes in African savannah ecosystems (
Eight to ten weeks seems to be the optimal exposure time for hay-bait traps in Central European conditions. A similar result was found by
Centipedes and millipedes inhabit the soil surface as well as the soil profile. For a complete knowledge of myriapod fauna, pitfall trapping needs to be combined with a method to collect soil dwelling species, e.g. soil sampling. Hay-bait traps were tested for their ability to replace soil sampling. Our results showed that hay-bait traps are attractive to myriapods and can have a similar sampling effort as soil sampling. The optimal length of exposure of hay-bait traps in soil seems to be ca 2 months (8–10 weeks).
This research was supported by grant of Ministry of Agriculture, No. QJ1230066 and European Project supported by the Operational Programme Cross Border Co-operation CZ-PL No. CZ.3.22/1.2.00/12.03445. We are also grateful for support of project CzechGlobe – Centre for Global Climate Change Impacts Studies, Reg. No. CZ.1.05/1.1.00/02.0073 and LC06073. We are grateful to Megan Short (Deakin University, Australia) for her English improvement as well as to Petr Dolejš and Jolanta Wytwer for their valuable comments and suggestions.