Bug FAQPortuguese Millipede
Ommatoiulus moreleti · Order: Julida · Family: Julidae
Also called: Portuguese black millipede, black Portuguese millipede
Adult Portuguese millipedes are smooth, 20 to 45 mm long and range from grey to black. They are native to the western Iberian Peninsula and have become invasive in Australia. When threatened they spray a yellowish fluid that can permanently stain clothes and irritate eyes.
Source: Wikipedia
How to recognize it
Adults are smooth, 20 to 45 mm long and coloured from grey to black.
Source: Wikipedia
Size
Adults measure between 0.8 and 1.8 inches in length.
Source: Wikipedia
Does it bite or sting?
When disturbed they release a pungent yellowish fluid containing quinones that stains clothing and irritates eyes. Because of this defense it is better to sweep them up rather than crush them.
Source: Wikipedia
How to get rid of it
Applying the nematode Rhabditis necromena has successfully lowered millipede numbers below concern thresholds in urban and semi-rural areas.
Source: Wikipedia
Where it lives
In its native range it prefers tree litter, especially oak and pine, with densities around five per square metre for stage 7 or older. In southern Australia it can reach over 40 individuals per square metre in grassland litter.
Source: Wikipedia
Life cycle
Mating occurs in autumn; females lay 60 to 80 eggs in a shallow soil chamber. Eggs hatch to a pupoid stage and then pass through up to 16 moults over three years.
Source: Wikipedia
When you see it
Adults are active on the surface during autumn and early winter, when they may be seen mating. In urban areas of southern Australia they enter houses during autumn and spring activity periods.
Source: Wikipedia
Where it comes from
It is indigenous to the western Iberian Peninsula. It was accidentally introduced to Australia, where it has become invasive.
Source: Wikipedia
More photos
Questions people ask
How do I keep Portuguese millipedes out of my house?
Use chemical or physical barriers, and consider biological control with the nematode Rhabditis necromena, which has reduced populations in South Australia.
Source: Wikipedia
What should I do if I crush one?
Avoid crushing them because they release a yellowish fluid that stains clothes and irritates eyes; instead sweep them up.
Source: Wikipedia
When are they most active?
They are active on the surface in autumn and early winter and may enter homes during autumn and spring.
Source: Wikipedia
Same family (Julidae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Ommatoiulus_moreleti
Look it up elsewhere: GBIF · iNaturalist · BugGuide · Wikipedia
Text written 2026-10-24 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-22.