Desis - Long-jawed intertidal spiders or lace web spiders

Family Desidae

ß Home


Fifty species in seventeen genera occur in Australia. Most species have an dark coloured ovoid abdomen, are medium-sized and smaller than 2 cm.
An important characteristic of this family is the wooly combed catching silk, which often has a shiny blue color. It is a cribellate web.
The spider combs its silk with a comb or calamistrum located on her rear legs. The comb is made of a row of small, stiff hairs.
 
The silk comes from an additional organ called the cribellum that contains of a lot of small spinnerets that deliver the small threads of silk. All spiders with a cribellum (Amaurobiidae, Eresidae, Oecobiidae Uloboridae and Dictynidae) are incorporated in a special group called the Cribellatae.
Cribellum

See also: The properties of silk

How does this wooly catching silk work? Around two closely located normal catching threads lies the wooly, combed catching threads. When an insect comes in contact with the wooly web, the barbed hooks of the insect get meshed in to the wooly silk. The threads of the wooly silk can stretch to ten times its original size. Therefore as the insect tries to free itself from the silk, it finds itself more and more snarled up into the mesh of the silk that keeps on stretching. All this time the spider is watching the show. After the insect is debilitated, the spider makes its move and kills the prey.


Spinners

Genus Badumna

This is a robust short-legged spider and one of them is known as the "black house spider" and inaccurately as the "Funnel-web spider".
Most of the 18 species are dark in color, often with a lighter or darker pattern on the abdomen. These spiders are also called house-spiders that can be found in and around building. Old webs become dense, felted and gray in appearance.
These spiders are not dangerous.

  Badumna insignis
Bandumna sp. Bandumna sp.
Badumna insignis (formely Ixeuticus robustus ) Badumna insignis in her retreat waiting for a prey that gets entangled in her web.
Badumna insignis is known as the Black house or window spider. The male has a length of 10-12 mm and the female 16-20 mm. They like to build their permanent web inside houses as her name suggests. Her web has a tubular retreat which spread out in a series of broad funnels. She is therefore sometimes, inaccurately, called Funnel-web spider. The web can measure up to 35 cm. The female make oval egg-sacs.
These spiders can be found around houses but also in woodlands and dry scerophyll forests in all states of Australia and in New-Zealand.
  Badumna insignis
Badumna longinqua Badumna longinqua
Badumna longinqua Badumna longinqua
Badumna longinqua is a common spider wide spread in Eastern Queensland. The male is 8-10 mm and the female 10-15 mm long. These spiders are dull-brown to dull black with white tuffs of hair. The female constructs a messy mass of silk threads that can be as large as 20 cm. The egg-sacs are positioned in the back of the web and every egg-sac contains 100-200 eggs. The spider feeds on beetles, flies and other insects. There are reports that in the north of Queensland she hunts green tree ants. (Oecophylla virescens) Badumna longinqua
  Badumna longinqua (formerly Ixeuticus martius )
Oecophylla virescens, green ants
Badumna_ZZ290
Badumna ZZ290 Badumna ZZ290
Badumna ZZ348
 

Genus Phryganoporus

Spiders of the genus Phryganoporus are cribellate web builders that are distributed throughout Australia. They build webs on low vegetation and their abundant white hair cover probably helps reduce body heating, particularly for spiders occupying exposed webs in semi-arid to arid regions.
While the species described here are typically solitary, one species, Phryganoporus candidus, has a life cycle that is associated with both communal and solitary webs. Phryganoporus candidus has long been known for its communal “nest” building behaviour.
The nest consists of branches and leaves knitted together silk. Inside the web are many tunnels wherein the spiders reside.
In past years the webbing of these spiders upon fruit tree foliage in the Riverina area of New South Wales was a cause of severe foliage matting, leaf fall and withering of limbs.
Most webs were founded in late summer by solitary subadult females. By October– November, at the peak of colony growth, each nest had about 100 spiders, along with an associated arthropod fauna of opportunist scavengers and predators. Most non-territorial, communal interaction (collective nest construction and cleaning, prey capture and feeding) took place between individuals below the subadult stage. Such communal interaction is probably a consequence of pheromone mediated sibling tolerance and is not regarded as true cooperative behaviour. Subadults males and females are less tolerant of each other. The faster maturing females dispersed over summer, most as subadults. Adult males did not appear in the nest until most of the females had dispersed. By March, the old nests were largely unoccupied.
Phryganoporus candidus head detail of the male Nest of Phryganoporus candidus, Hamelin pool - WA June 2006
Phryganoporus candidus female Phryganoporus candidus male
Phryganoporus nigrinus Phryganoporus nigrinus
Hiding place of Phryganoporus nigrinus Phryganoporus nigrinus
Phryganoporus nigrinus Phryganoporus nigrinus
Phryganoporus information and spinner and cribellum pictures f rom: GRAY, MICHAEL R., 2002. The taxonomy and distribution of the spider genus Phryganoporus Simon (Araneae: Amaurobioidea: Desidae). Records of the Australian Museum 54(3): 275–292.


Ed Nieuwenhuys 20 december 2006
Ronald Loggen 1998,2005

Copyright ã 1997-2006