St Nicks

Centre for nature and green living

February 2015: Spotlight on… Creatures found under logs and stones

Red-spotted Snake Millipede

Red-spotted Snake Millipede

Ground level at St Nicks reserve offers a sheltered home for many creatures, particularly in the leaf litter or under stones, bricks and decaying logs. Over the past year the Wildwatch group has spent a little time exploring this hidden world, whose inhabitants include worms, slugs, snails, woodlice, centipedes, millipedes, spiders, ground beetles and various other small things that prefer life in the dark.

Little attempt has been made so far to identify the several species of worms, snails and slugs, though one of our team is now onto slugs!

Centipedes and millipedes may seem similar animals, but millipedes always have two pairs of legs to each body segment while centipedes have one pair. A centipede won’t stay around long to let you look at it – it’s a fast mover and scuttles down the nearest cavity. Millipedes however seem to have all day, curling into a spiral or moving like a tortoise. The Wildwatch team have identified two species of centipede: the larger but shorter common species Lithobius forficatus and the long thin Burrowing centipede Stigmatogaster subterranea. Centipedes account for 40% of all woodlouse predation. Four species of millipede are regularly seen: Flatbacked Polydesmus angustus, Blue-tailed Snake Cylindroiulus punctatus, Spotted Snake Blaniulus guttulatus and Whitelegged Snake Tachypodoiulus niger. The latter is known to wander widely at night and even climb trees, though this behaviour has not been observed at St Nicks!

Woodlice have revealed some of their secrets too. Five species have been identified and are frequently seen: Common Pill Armadillium vulgare, Common Shiny Oniscus asellus, Common Striped Philoscia muscorum, Common Rough Porcellio scaber and most recently the tiny Common Pygmy Trichoniscus pusillus.

Clockwise from top left: White-legged Snake Millipede; Common Striped Woodlouse; Ground Beetle; Common Shiny Woodlice

Clockwise from top left: White-legged Snake Millipede; Common Striped Woodlouse; Ground Beetle; Common Shiny Woodlice

Harvestmen (related to spiders) are sometimes seen under logs or stones, in particular a small black harvestman with white patches on its legs, feeding on small creatures in the leaf litter or under decaying wood: Nemastoma bimaculatum.

Various species of springtail spring out of the way when disturbed, but the final creatures of note are the ground beetles, some of which have mouthparts adapted to seizing springtails. Not easy to identify to species level, we believe we have seen four kinds of ground beetle under logs and stones at St Nicks: two Pterostychus species: madidus and nigrita and two Leistus species: the red ferrugineus, and fulvibarbus which is black with reddish-orange legs. Finally, living in rotting wood we have seen the Lesser Stag Beetle Dorcus parallelipipedus.

Logs and stones provide hiding places and living spaces for a great many creatures – many many more than we have listed above. Some use the space all year round, others for part of the year, and still others use the crevices as food opportunities. The Wildwatch team has only begun to scratch the surface (!) of this rich warm moist habitat. In terms of species per square inch it seems greatly more abundant than most other habitats on the reserve.

All photos here were taken at St Nicks

Snake Millipede

Snake Millipede

18 February 2015 | Categories: Spotlight on..., Wildwatch | Tags: Centipede, Ground Beetle, millipede, Springtail, Woodlouse