Hedgehog harvestmen

With winter slowly extending its icy tendrils throughout the country, many of our invertebrates seek to see out these long, cold months by overwintering to await the coming of spring. However some species remain busily active, especially those close to the soil surface and amongst the leaf litter where it’s warmer and the food is more abundant. Whole life histories are played out in and above this humus-rich environment and this includes the fascinating lives of our Harvestmen and one very rare individual indeed, the Hedgehog Harvestmen

Fast Facts

Latin name: Centetostoma bacilliferum

Notable feature: Black and gold colouration, spine-like warty growths or ‘tubercules’ on its abdomen

Where in the UK: Only found in Plymouth

Land strider!

Harvestmen are ancient cousins of spiders but have developed very unique physical characteristics, a single fused body, long, threadlike legs and a raised growth on the top of the body housing a simple pair of eyes. They lack any ability to spin webs like spiders spinnerets so they scavenge and hunt for their food, striding effortlessly from leaf to twig to stone with those spindly legs, in search of a tasty morsel. They possess a pair of pincer-like jaws called chelicerae which can carefully pick at food in the manner of a crab, and are aided by a pair of pedipalps, appendages either side of the jaws which can act as feelers for exploring their immediate environment.

A side-serving of bird poo…

The diet of harvestmen such as the Hedgehog harvestmen is wide and varied. As omnivores, harvestmen will consume dead plant matter, carrion, even bird poo! They will hunt prey too; they have a liking for small, soft-bodied invertebrates including aphids and mites, which also makes them the gardener’s friend.  Other species of harvestmen can be found deep amidst the soil and sometimes at the bases of grass stems.  These often have legs that are very short, enabling them to move through the soil and undergrowth rather than over it.

A winter rarity

Whilst many species of harvestmen are more commonly found in the autumn, a few do persist through the winter. The Hedgehog harvestman is one of the rarest species in the British Isles, found only in Plymouth and not until as recently as 1990 with only around 70 specimens ever discovered. It is a striking invertebrate, coloured black and gold and has a very spiny appearance thanks to an array of spine-like nodules across its body. Not a great deal is known about its life history but so far it has been found from early summer straight through until January.

Where do they live?

The Hedgehog harvestmen is only associated with a disused railway that once bisected Plymouth. Its habitat consists of hiding amid grass tussocks and under stones and old railway sleepers that remain on the old train line.

Did you know?…

Harvestmen do not possess any venom like spiders but have ‘odiferous’ glands which produce a foul-smelling liquid which they use against predators.