Millipede *Pachyiulus flavipes* Smell

Hello,

Does anyone know what chemical causes the smell of the millipede Pachyiulus flavipes. There are a lot of them coming into the house to hibernate at this time of year and they have a very distinctive smell, not a bad smell exactly, just unusual.

Thank you…

Apparently, there are several compounds. According to the abstract of Millipedes that smell like bugs: (E)-alkenals in the defensive secretion of the julid diplopod Allajulus dicentrus from PubMed.gov by Michaela Bodner and Günther Raspotnig in 2012:

…In adults, 13 components from two chemical classes were detected: 1) The common juliform benzoquinones were represented by four compounds (2-hydroxy-3-methyl-1,4-benzoquinone, 2-methoxy-3-methyl-1,4-benzoquinone, 2,3-dimethoxy-1,4-benzoquinone, and 2,3-dimethoxy-5-methyl-1,4-benzoquinone). From this series, 2-methoxy-3-methyl-1,4-benzoquinone was most abundant, comprising about 40 % of the whole secretion. 2) All remaining compounds were identified as aliphatic (E)-alkenals [(E)-2-heptenal, (E)-2-octenal, (E)-2-nonenal, (E)-2-decenal)] along with their corresponding alcohols. (E)-2-Octenal was most abundant, roughly accounting for another 35 % of the secretion. In juveniles, different stages in the ontogenetic development of the secretion were observed, with early instars (stadium III and IV) exclusively containing the benzoquinone fraction. Alkenols and alkenals were added in later instars (stadium V and VI), with secretions of stadium VI-juveniles being already similar to those of adults. Representatives of Spirostreptida, Spirobolida, and Julida traditionally have been considered to produce benzoquinonic secretions only (“quinone millipedes”),…

I know it is not the exactly same Millipede, but I hope this answers your question.