Mouse Spider - Australian Museum

ANIMAL SPECIES:Mouse Spider

Why 'mouse' spider? No good reason, but possibly the name was given for the large, supposedly 'mouse-like' burrows built by the big inland Red-headed mouse spider.

Number of species

10 described species in Australia

Identification

These spiders have a smooth, glossy carapace and their head area is high and broad with very large, bulbous jaws. Mouse spiders' eyes are widespread across the front of their head. The spinnerets, at the back of the abdomen, are short and blunt, the last segment domed and button-like. Females are black overall and are larger than the males, especially in the Red-headed Mouse Spider. Males have long slender pedipalps and some species have distinctive colour markings but others are balck overall. Male mouse spiders do not have mating spurs on their legs.

Male Eastern Mouse Spiders (Missulena bradleyi) are black with a bluish white patch on the front of the abdomen.

Male Red-headed Mouse Spiders (Missulena insignis) have a red head and jaws, and a gunmetal blue abdomen. Female Red-headed Mouse Spiders are dark brown to black, and the jaws are sometimes red-tinged, but they are very different in overall size and appearance, which led to confusion when the species was first being described.

Size range

1 cm - 3.5 cm

Similar Species

Trapdoor Spiders and Funnel-web Spiders

Distribution

Mouse spiders are widely distributed across the mainland.

Eastern Mouse Spiders (Missulena bradleyi) are found in coastal and highland regions of eastern Australia.

Red-headed Mouse Spiders (Missulena insignis) have the largest distribution of mouse spiders and are found across the continent mainly west of the Great Dividing Range.

Habitat

Mouse spiders can be found in open forest to semi-arid shrubland habitats.

Like the trap-door spiders, the mouse spider lives in burrows in the ground, often in banks of rivers, creeks and other waterways, and is sometimes found in suburban gardens. The burrows are built with double or single trapdoors and the entrance is oval-shaped. Some species have a side chamber extending of the main burrow shaft, usually closed by a trap door. It provides a refuge from pedators and a safe place for the egg sac and spiderlings. The burrow can extend for a depth of about 30cm - which is unusually deep for a spider, but not as deep as previously claimed for this species.

Behaviour and adaptations

Seasonality

The males of several mouse spider species can be seen wandering about by day during the late summer to early winter months (especially after rain).

Feeding and Diet

Insects are the main prey of Mouse Spiders but their diet could possibly include small vertebrates and other spiders.

Other behaviours and adaptations

The females tend to remain in or near their burrows throughout their life, and are sluggish spiders that are rarely aggressive. However Missulena occatoria females have been found to produce copious amounts of highly toxic venom, which is potentially as dangerous as that of the Sydney Funnel-web Spider.

A male easternmouse spider (M. bradleyi) caused a serious envenomation in a child in the Brisbane region. Males wander during early winter, especially after rain. They will assume a threatening posture if disturbed.

Life cycle

The female lays 60 or more eggs within an egg sac that she places into a brood chamber off the main shaft of her burrow. The spiderlings hatch from the egg sac over summer and remain with the mother into autumn when dispersal occurs.

The spiderlings of the Red-headed Mouse Spider disperse by ballooning, a technique that is rare in mygalomorphs. This explains the relatively wide distribution of Red-headed Mouse Spiders compared to other mygalomorph species, including the Eastern Mouse Spider, which probably disperses on the ground.

Mating and reproduction

Males reach sexual maturity at about four years. They leave their shallow burrows during the breeding season to find a mate. They are unusual in that their wandering behaviour occurs during the day, unlike other mygalomorph spiders, whose males are night wanderers. While wandering, male mouse spiders hold their long pedipalps (carrying the mating organs) extended forwards, presumably seeking an airborne scent (pheromone) associated with the femaleor its burrow. Once the burrow is located the male taps the ground and silk around the doors until the female emerges. If she is receptive the male follows her into the burrow where mating occurs.

Predators, Parasites and Diseases

Predators of the Mouse Spider include parasitic wasps, bandicoots, scorpions and centipedes.

Living with us

Danger to humans and first aid

Mouse Spider venom may be very toxic, but few cases of serious envenomation has been recorded. Other bites have occurred causing minor effects. Funnel-web spider antivenom has proved effective in the one confirmed case.

Until more toxicity data is available it is prudent to treat as for Funnel-web spider bite, especially if the victim is a child. Apply a pressure bandage over the bitten area as high up the limb as possible. Immobilise the victim. Collect the spider for positive identification. Do not wash venom off the skin, as retained venom will assist identification.

Classification

Genus:: Missulena
Family:: Actinopodidae
Suborder:: Mygalomorphae
Order:: Araneae
Class:: Arachnida
Phylum:: Arthropoda
Kingdom:: Animalia

What does this mean?

References

Simon-Brunet, B. 1994. The Silken Web: a natural history of Australian Spiders. Reed Books.
Sutherland, S.K. & Nolch, G. 2000. Dangerous Australian Animals. Hyland House.
York Main, B. 1976. Spiders. Australian Naturalist Library, Sydney.

Last Updated: 23 December 2009

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