Saturday, 3 October 2015

Linyphiidae: sheet weavers and money spiders

Linyphidae is the largest spider family in the UK, with 270 species. Most of these are tiny, dark and and only identifiable with a microscope, the 'money spiders'. They typically build hammock-like webs held by a pattern of criss-crossing threads above and below. Liniphids usually hang upside down from their sheet web and do not use a retreat.
One of the largest species is the common Linyphia triangularis (above) whose webs hang in numbers from bushes in gardens and become very evident when covered in dew.
Neriene montana, is another large species (4-7 mm) common in gardens.

Stemonyphantes lineatus.

Gosammer and ballooning
These spiders can be incredibly numerous and active, and their drag silk threads can give fields a silvery shine, which is called gosammer. Money spiders disperse by ballooning. They climb up bushes and release a long silk line, which can get caught in the wind. Standing on tiptoes, the spiders are pulled up and lifted into the air.

A close-up of a gossamer-covered grass seed-head with money spiders ready to balloon.

Mating tactics
Linyphia has some interesting mating tactics I have blogged about before. Males have large chelicerae they use to fight other males while they guard a female.
Linyphia triangularis pair, the male is on the foreground. Males often sit on the female's web, mate guarding.

Money spider heads
Some money spiders have very unusual heads, with some of their eyes on top of turrets or humps (see if you can make sense of Walckenaeria!). These harbour glands that produce secretions, possibly nuptial gifts, during mating. Females of some species are known to hold the male's head during mating.

Egg sacs
Egg sacs are set near the web, and the females can sit on top of it guarding it.
Neriene montana near her translucent egg sac.

1 comment:

conall said...

Great info and pictures Africa- there seem to be loads of Linyphia triangularis around me at present.