*Pic: A handsome native iulomorphid
If you looked at the image above and said “Eeeeuggh!”, maybe you need to have a quiet chat with yourself about the Tasmanian fauna.
It ain’t all birds and cutesie-poo mammals. In fact, hardly any of our fauna is birds and mammals. Most of it is bugs, snails and worms, and believe it or not, their importance in nature isn’t to provide birdfood.
Take millipedes, for example. They’re part of the food web that recycles plants. Very little plant growth of any kind gets eaten by animals while the plants are still green. Most plants just die and rot away, to be recycled as soil and carbon dioxide.
The rotting-away is done by fungi and bacteria with the help of creatures like millipedes. The particular millipedes featured here are specialists. Together with fungi, they turn whole dead trees into soil, which is why you mainly find these millipedes inside rotting logs or just underneath them.
That’s mainly where I find them, at least. I study millipedes, and I’ve been collecting them in Tasmania since the 1970s. We have about 200 native species.
Until recently the long, dark millipedes, as in the top image, didn’t have names and it wasn’t clear how many different species of them lived in Tasmania. After examining a couple of thousand museum specimens and collecting some more, I’ve sorted them to 13 species in three different genera and published the results in a scientific journal.
Like all scientific names, the ones I’ve given to the new species can be a little hard to pronounce and remember, but as a group these particular millipedes are called “iulomorphids”, pronounced YOU-low-MORE-fids.
An interesting finding about our iulomorphids is that in the biggest genus of 10 species, most are easterners. Between Falmouth and Orford there are five species in that genus, with three species co-occurring in parts of the Eastern Tiers. Another species is only found on Forestier and Tasman Peninsulas, the seventh only near Hobart and the eighth only in the Tamar Valley and the Northeast. They all look much like the species in the image above.
Native iulomorphids have been slowly disappearing in southeast Tasmania. Part of the explanation is the continuing conversion of bush to pasture and residential land, but there’s a villain in the story, too. It’s the similar-looking Portugese millipede, an exotic species that swarms in spring and autumn and invades houses around the State. In dry woodland, Portugese millipedes can completely replace our native millipedes. It’s hard to find iulomorphids these days on Hobart’s Eastern Shore, where the Portugese millipedes number in the millions.
You can tell invader from native in two ways. Pick the millipede up and if it wriggles vigorously, it’s an exotic pest. If it coils into a tight spiral and stops moving, it’s a native. The other way is to look closely at the tail end. Portugese millipedes have a little point on their tails, while all our natives have rounded bums.
If you’re very patient you could count legs. Our iulomorphids have a lot more legs than Portugese millipedes do. The champion Tasmanian iulomorphid comes from the Fingal Valley. It has 270 legs and is almost 8 cm long, and to my eyes it’s very handsome.
Boo! Hiss! … A Portugese millipede
Dr Robert Mesibov,
West Ulverstone, Tasmania, Australia
Website(s): http://www.polydesmida.info
*Bob Mesibov is retired and lives in Ulverstone. When he’s not in the bush hunting millipedes he’s often busy coding. His scientific papers are listed here [ http://www.polydesmida.info/mesibov.html ] and his coding efforts here [ http://www.polydesmida.info/coding.html ].
• Ted Mead in Comments: Thanks Bob – An informative article about these cute critters that most people take for granted. Insofar as invertebrates go there is an entire kingdom waiting to be discovered on the forest floor. All the more reason why the clearfell and burn regime is an appalling way to manage our forests. Unearthing the soil and burning every bit of humus that exists has a devastating effect on the complex biota of what’s happening beneath our feet.
• Bob Mesibov in Comments: … How does this sound?: “What I don’t understand is that there are scientists/entomologists who adore, and are fascinated by the invertebrate world, yet they still justify the farmer’s position of superfluously destroying millions of these creatures paddock after paddock, creek after creek” … My wife and I arrived in Tasmania in the early 1970s, and we can remember seeing bush alongside many roads where there are now vast paddocks. In forestry areas I can still, today, collect the bugs in regrowth that I collected in oldgrowth 40 years ago. I can’t do that in the paddocks. The bugs that were there 40 years ago are gone.
