Cave Spider

I was fortunate to be involved in a survey of this  handsome spider (Meta menardi) in Jesmond Dene. They are one of the largest spiders, at 5cm leg span, found in the UK.

After mating, female produce a round egg sac or cocoon shown below. Cocoons are tear shaped white pendants usually hanging from the roof of the habitat by a silk thread approximately 20 mm long. The cocoon (2–3 cm in radius) contains an average of 200/300 eggs and is laid near the cave entrance at the end of the summer. After hatching, the young spiders remain in the cocoon until the first moult, feeding on the yolk. They leave the cocoon in spring, move towards the cave entrance and disperse via ballooning silk threads outside the cave.

The adults are photophobic so disturbance was kept to a minimum. They emerge around dusk to hunt, often using a single silk lasso line and swinging down upon their prey. Herald moths which also like to overwinter in caves often fall victim to the spider as revealed below. Caddis flies also form an important part of their diet.