Alkyldimethylpyrazines in the defensive spray of Phyllium westwoodii: a first for order Phasmatodea

J Chem Ecol. 2009 Aug;35(8):861-70. doi: 10.1007/s10886-009-9666-9. Epub 2009 Aug 15.


Phyllium westwoodii is a phasmid insect (Order Phasmatodea) belonging to the Family Phylliidae (leaf insects). These rather large and ornate creatures are known for their morphological resemblance to plant leaves for camouflage. Pyrazines are a common class of compounds used or produced by a wide variety of organisms, even humans. When an individual of P. westwoodii is disturbed, it sprays an opaque liquid from a pair of prothoracic glands, which are utilized by other phasmid species for defense. The current study has found that this liquid contains glucose and a mixture of 3-isobutyl-2,5-dimethylpyrazine, 2,5-dimethyl-3-(2-methylbutyl)pyrazine, and 2,5-dimethyl-3-(3-methylbutyl)pyrazine. This is the first report of pyrazines found in the defensive gland spray of phasmid insects, and the first chemical analysis of glandular material from family Phylliidae.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Gas Chromatography-Mass Spectrometry
  • Insecta / anatomy & histology
  • Insecta / physiology*
  • Magnetic Resonance Spectroscopy
  • Pyrazines / chemistry*
  • Pyrazines / isolation & purification


  • 2,5-dimethyl-3-(2-methylbutyl)pyrazine
  • 2,5-dimethyl-3-(3-methylbutyl)pyrazine
  • Pyrazines
  • 3-isobutyl-2,5-dimethylpyrazine