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Chemical composition of defensive fluids in the millipede Polydesmus collaris from Mt.
Avala, Serbia

Konstantin Kostić
Center for talented youth Belgrade II, Belgrade, kostic.prof@gmail.com

1. Introduction Table 1: Chemical composition of the defensive secretions in
the Polydesmus collaris C. L. Koch, 1847 analyzed by GC-MS.
Millipedes or Diplopoda are an ancient and one of the
widespread group of animals, comprising more than 12,000 Compound Rt (min) Relative abundance
(%)
species [1]. These arthropods are also known as chemical 1 Benzaldehde 6,6 55,9
warriors. Most of the millipedes possess repugnatorial glands 2 Benzoylnitrile 11,1 42,3
(ozadens) on pleurotergites, with different composition of 3 Benzyl methil ketone 12,6 0,4
defense secretion depending on the taxonomic group. Most 4 Benzyl ethil ketone 16,9 1,0
members of the order Polydesmida are known as cyanogenic 5 2-Methil-1,4- 29,4 0,1
naphtoquinone
millipedes due to the production of HCN and cyanogenic 6 Mandelonitrile 45,2 0,1
compounds [1]. Until now, chemical composition of defensive benzoate
fluids in millipedes is known in less than 2 % of species [2]. 7 Benzoic acid 51,9 0,2
2. Objective
The aim of this work was to determine and identify the
chemical components of the defensive secretions from analyzed
species, to test for possible interspecies variation of the
chemical constituents with previously analyzed forms, and
confirm the consistency of cyanogenesis in the member of the
order Polydesmida.

3. Materials and methods
Specimens of P. collaris were collected in the autumn
(September 2013) at Mt. Avala, near Belgrade. Polydesmids
were stored in plastic boxes with a layer of litter and soil and Figure 1: GC-MS total ion chromatogram of hexane extract of
kept in the laboratory for a few days. Humidity in the boxes Polydesmus collaris C. L. Koch, 1847. Number of peaks
was kept high by spraying water every day. Chemical analyses corresponds to the number of compounds in Table 1.
were performed on an Agilent 7890A GC system. A library
search and mass spectral deconvolution and extraction were 5. Conclusion
performed by using NISTAMDIS (Automated Mass Spectral
Deconvolution and Identification System) software, ver. 2.64.
With the execption of a few noncyanogenic Polydesmida [4]
4. Results and discussion the majority of polydesmoid millipedes are cyanogenic, which
Analysis of defensive secrets in P. collaris showed presence of was confirmed by this study. Analyzed polydesmids have
eight compounds (seven compounds in Table 1; presence of specific chemoprofile, clearly different from previously
HCN was confirmed by picric acid test). Two major analyzed species. Eight detected compounds have allomonal
components were benzaldehyde and benzoylnitrile. No functions, but some of them may also have some antimicrobial
significant difference in the amounts of the components was or antifungal properities.
observed between the sexes in the analysed species.
Benzaldehyde and HCN are known as the most common References
defensive substances in various polydesmids [3], and in [1] S. Hopkin, H. Read: The Bioilogy of Millipedes. New York,
analyzed species have allomonal function. 2-Methil-1,4- Oxford University Press, (1992), 233pp.
naphtoquinone was detected for the first time within whole [2] O. Eisner, D. Alsop, K. Hicks, J. Meinwald: Defensive
order Polydesmida. On the other hand its presence showed secretions of millipedes. Pp. 41. In Bettini (Ed.) Arthropod
venoms. Springer Verlag, Heidelberg Berlin (1978).
specific chemoprofile of analyzed species. Presence of [3] S. Makarov, B. Ćurčić, V. Tešević, M. Jadranin, Lj. Vujisić, S.
mandelonitrile benzoate in defensive fluids is interesting Ćurčić, B. Mandić, T. Sekulić, B. Mitić: J. Chem Ecol. 35, (2010),
because it may represent the mechanism that stabilizes 978-982.
mandelonitrile if the specimen is consumed by a predator [4]. [4] Y. Kuwahara, N. Shimizu, T. Tanabe: J. Chem. Ecol, 37,
(2011), 232-238.