Tropical millipedes can grow to be very large and Seychelles has a giant one. The Seychelles Giant Millipede (Seychelleptus seychellarum) is one of the largest millipedes in the world (the African Giant Millipede is the largest) regularly reaching over 15 cm in length. Once found on all islands in the granitic group, it is now most abundant on seabird islands free of introduced predators like Cousin, Cousine, Félicité, Aride and Frégate.
Millipedes have two pairs of legs on each leg segment. The name “millipede” is a compound word formed from the Latin roots mille (“thousand”) and pes (“foot”), although none is known to have 1000 legs! Common species have between 36 and 400 legs.
Millipedes move quite slowly and can be easily distinguished from the somewhat similar and related centipedes, which move rapidly (Seychelles also has a giant centipede). Although giant millipedes move rather slowly, they are powerful burrowers. With their legs and body length moving in a wavelike pattern, they easily dig their way underground head first. They also seem to have some engineering ability, reinforcing the tunnel by rearranging the particles around it.
Adults of the Seychelles Giant Millipede are a glossy dark brown-black colour, while juveniles are a bright red-brown. The giant millipede is a harmless vegetarian that relies on its tough cuticle and irritating chemical defence to protect it from predators. The chemical is fairly harmless but can be irritating to human skin sometimes causing itching and pain. The millipede feeds on leaf litter and other plant material and is mainly nocturnal. For this reason, it is susceptible to being squashed when it wanders onto footpaths at night.
The Seychelles Giant Millipede is listed as ‘Vulnerable’ on the IUCN Red List of Threatened Species. Conservation of the Seychelles Giant Millipede involves maintaining the forest canopy under which it lives.
(Photo credit: Peter Chadwick)