HARVESTMEN
ABOUT twenty species of Harvestmen have been recorded in Nottinghamshire. These familiar creatures are often encountered in our gardens and houses and are often assumed to be spiders.
They are Arthropods and belong to the same Arachnida class as spiders but are classified in the Opiliones order – whilst spiders are grouped in the Araneae order.
The name Harvestmen is derived from the fact they are seen in late summer and autumn, coinciding with harvest time.
Harvestmen are a common and widespread group of long-legged invertebrates and about 25 species live in the UK.
The Common Harvestman (Phalangium opilio) is reddish-brown on top and white below; females are larger than males. The fangs are quite prominent.
Harvestmen have eight legs but, unlike spiders, they don’t have a separate abdomen, and as such no waist. This physical feature is the easiest way to separate a harvestman from a spider. Typical body length does not exceed 7 mm (0.28 in) although their long legs make them look much larger. Harvestmen do not have silk or venom glands and as such present no hazards to humans. Similarly to scorpions, some species will glow under UV light.
Most species are nocturnal and generally brown coloured with a single pair of eyes in the middle of the head, oriented sideways. Typically, the second pair of legs are slightly longer than the other three pairs and used as ‘feelers’ to explore the environment ahead of them. When attacked they have the ability to shed a leg which continues to twitch after it has been detached, usually for a minute or so, but some have been recorded twitching for up to an hour. It is believed that this leg twitching is a
means to distract the predator whilst the harvestman escapes.
They tend to be omnivores, using their sensory legs to prey on small insects as well as eating plant material and fungi. These arachnids defend themselves by secreting a foul-smelling fluid. After feeding they clean their legs by drawing each one in turn through their jaws. Following mating, the male of some species will guard the eggs, often against their mate. Eggs typically hatch after 20 days, and the resulting nymphs mostly pass through six different stages (instars) before reaching maturity. Keep a look out for these small but very interesting arachnids and notice how different they actually are from spiders.
In the US, harvestmen are referred to as “Daddy Longlegs” but in the UK we tend to use this name when referring to a large type of cranefly; the gangly insect that always seems to find a way into our homes in the summer and autumn.
Craneflies lay their eggs in the ground and the larvae, known as leather jackets, live underground feeding on plant roots and stems causing unsightly bare patches in garden lawns, and are considered garden pests. Crows, magpies, rooks and starlings will actively seek out these grubs in the ground leaving small tell-tale holes in the ground where they have inserted their beaks. On a positive note for gardeners the birds provide some aeration for the lawn in their search for these leather jackets.