Ground spiders comprise Gnaphosidae , the seventh largest spider family with over 2,000 described species in over 100 genera distributed worldwide. There are 105 species known to central Europe,and common genera include Gnaphosa, Drassodes, Micaria, Cesonia, Zelotes and many others. They are closely related to Clubionidae.At present, no ground spiders are known to be seriously venomous to humans.
Ground spiders, known scientifically as the Gnaphosidae, make up the seventh largest spider family globally. They have a diverse range of species that contribute significantly to the ecosystem. This article will dive into the fascinating world of these nocturnal hunters, providing an in-depth look at their features, behaviors, habitats, and their importance in the ecosystem.
Characteristics of Gnaphosidae:
anterior spinnerets well separated, tubular, often long extending beyond the end of the abdomen giving the spider the appearance of having two exhaust pipes at the back dark brown, black, or reddish posterior median eyes often odd-shaped and very reflective (shiny) small to medium sized found on ground, often under debris Ground spiders are sometimes difficult to find. They hide under rocks and logs during the day and hunt primarily at night. Most of the species are dark-colored with relatively long legs. Even the groups (genera) are difficult for non-specialists to identify. One species, the Parson Spider, is common in houses, and adults of this species may be found at any time of the year. The genus Micaria contains a number of small, daytime-active runners. Members of this genus resemble the appearance and behavior of ants.
Identification
- many different kinds; typically earthtone coloration
- found crawling around (not within a web)
- two large spinneretts sticking out the rear of the abdomen are even in size throughout their length (rather than tapering toward the end)
Nesting Habits
- found in leaf litter, grasses, ornamental plantings, areas around buildings
- make web chambers in which they lay eggs
- are active hunters that wander in search of food
Diet
- insects and other spiders
Significance
- nuisance when indoors
- not known to be a health hazard
- beneficial
IPM Recommendations
- Minimize nesting habitat around property.
- Seal exterior cracks and crevices.
- Install tight-fitting door sweeps at the base of all exterior doors.
- Vacuum individuals that enter buildings.
- Step on or smash individual spiders that enter.
- Catch and release (with a glass jar) spiders found indoors.
- Change exterior lighting to sodium vapor bulbs.
- Use pest monitors to capture invading spiders, especially between August and October.
Ground Spiders are a vast and diverse group of spiders found all over Australia from rainforests to deserts.
Identification
Ground spiders are rather drably coloured, ranging from charcoal grey to pinkish brown. Some, like Anzacia, have shiny, iridescent hairs. Typically they have large, cylindrical front spinnerets that are well separated from each other. The middle eyes in the rear row are usually angular rather than rounded in shape.
This family contains a large number of varied spiders. Many species are dull brown with stocky legs, though some have bright patterns. They have quite distinct spinnerets that are of a uniform thickness (not tapering to a point), and are often positioned well apart, appearing as a two stubby tails from above. They are wandering hunters , and as the name suggests many species are found at ground level within leaf litter and beneath rocks and logs. They are mildly venomous and regarded as harmless spiders.
Habitat
Most Ground Spiders are vagrant hunters that are especially common in forest and woodland habitats, living in leaf litter and under bark. Some are highly specialised.
Distribution
Ground Spiders are found Australia-wide.
Other behaviours and adaptations
The Slit Spider of inland red sand-dune habitats makes a burrow with a wide, horizontal slit opening on the down-slope of a dune. The lower edge of the slit projects out beyond the upper edge, so that insects running down slope across the slit are guided into the cavity where they are grabbed by the waiting spider. Other Ground Spiders such as Hemicloea, are remarkably flattened for life in narrow spaces under rocks and bark.
Spotted Ground Spiders
The Spotted ground spiders Habronestes and Storena are two genera of spiders in the family Zodariidae.
Identification
Spotted ground spiders are from 6 mm to 20 mm long. They are usually dark-coloured (reddish to black), and sparsely haired. Legs are orange to red or black and white. They have two to five pairs of white or coloured spots on the dorsal surface of the abdomen that can range from pale yellow to bright orange. When present, an unpaired spot occurs just above the spinnerets. A characteristic feature of Storena is that they have a pale brown, pitted circle of bare cuticle between the front spots. The eyes are in two back-curved rows of four. One species of Storena is an ant mimic, resembling the red meat ants, Iridomyrmex purpureus. They mingle with the ants in their nest in the early mornings, when the ants are sluggish, and carry off the weaker ants as prey.
Habitat
Spotted ground spiders don’t build a snare, but hunt and ambush ground dwelling insects. Like many spiders, little is known about their biology. Some species build burrows in the ground or shallow depressions, and build a palisade (fort-like structure) of vertically arranged twigs or leaves around the entrance. Some species, like Habronestes bradleyi, are closely associated with ants.
Other behaviours and adaptations
Male spotted ground spiders live a vagrant life hunting or searching for females; they may be found in leaf litter, under logs or rocks, or even indoors wandering across the floor. In contrast, the females have rarely been observed far from the burrow. The oval egg sacs have a papery texture, and hold about 50 eggs.
Wandering males frequently enter houses at night, and their bright colours can cause alarm. The males also have characteristic club-shaped palps and can look quite threatening when these are held aloft. Despite the heavy appearance of their fangs, these spiders are reluctant to attack and timid when confronted.
Danger to humans
Few bites by these spiders have been reported and when they have, symptoms have been minor, consisting of a red welt and localised hot feeling for a couple of hours. They are not considered dangerous.
