Exotic species
Hackled orbweavers (Uloboridae)
Feather-legged lace weaver (Uloborus plumipes)
Web: horizontal (!) orbweb of 15 to 30 cm.
Habitat: The Feather-legged lace weaver is originally a tropical species that was imported in Belgium through the Mediterranean. It is almost exclusively found in heated spaces such as greenhouses. In garden centres you can spot the typical webs, hung between cacti and succulents. This species has only once been found outdoors in Belgium.
How to recognize:
- abdomen densely covered with hairs and two obvious humps
- colour varies from beige to almost black
- front legs with striking hair bristles.
Looks similar to:
The very noticeable abdomen, together with the specific occurrence in heated spaces means that this species is easily recognized.
Size
♀: 4-5 mm
♂: 3-4 mm
When?
Can be found throughout the year.
Cellar spiders (Pholcidae)
Marbled cellar spider (Holocnemus pluchei)
Web: an open, messy, 3D web, often with a dome like structure.
Habitat: almost always in (non)heated industrial buildings such as warehouses, hangars or garden centres. Often in corners.
How to recognize:
- spider with elongated abdomen and long, thin legs
- abdomen with light brown/grey colour and a clear, white, marbled drawing.
Looks similar to:
- can be confused with the Long-bodied cellar spider. However, the Marbled cellar spider has a clear, black band on the underside of the abdomen. The abdomen als has much more explicit drawing.
Size
♀: 5-7,5 mm
♂: 5-7 mm
When?
♀: throughout the year
♂: throughout the year
Cobweb spiders (Theridiidae)
Southern black widow (Latrodectus mactans)
Web: fairly large, 3D web with messy threads and often vertical threads with glue on the lower part towards the substrate (“gum footed threads”).
Habitat: The Southern black widow has not yet established permanent populations in Belgium. Observations are always the result of unintended hitchhiking from the original range (southern part of USA and Mexico). A lot of Southern black widow spiders are introduced by shipments of second-hand cars from USA in the Antwerp harbour.
How to recognize:
- shiny, black spider with round abdomen
- upper side of the abdomen always completely black
- under side of the abdomen: clear red hourglass drawing.
Looks similar to:
- False black widow spider: the clear, red hourglass marking is a sure identification characteristic of the Southern black widow which is lacking in the False black widow spider. The Southern black widow is also much larger than the false black widow spider.
- Other black widow species: often only distinguished by careful study of reproductive structures under a stereomicroscope.
Size
♀: 15 mm
♂: 6 mm
Zoropsid spiders (Zoropsidae)
Spiny false wolf spider (Zoropsis spinimana)
Web: The Spiny false wolf spiders doesn’t make a web, but is an active and visual hunter.
Habitat: Mainly in and around houses. In Southern-Europe underneath stones, bark. Hunts at night.
How to recognize:
- large spider
- yellow brown to grey brown colour
- abdomen with black cardiac mark that looks constricted
- cephalothorax with complex and light markings
- annulated legs
Looks similar to:
- looks at first sight like a large wolf spider. However, large wolf spiders will almost never be found in or near houses..
Size
♀: 10-19 mm
♂: 10-13 mm
When?
♀: throughout the year
♂: throughout the year
Eutichurid spiders (Cheiracanthiidae)
Yellow sac spider/Spiny false wolf spider (Cheiracanthium mildei)
Web: The Yellow sac spider doesn’t construct a web, but catches its prey through active, visual hunting.
Habitat: The Yellow sac spider can be found in a sac-like retreat in a curled up leaf or underneath stones and bark. In Belgium especially close to or in buildings (but recently also in a nature reserve, far removed from buildings.
How to recognize:
- medium size spider with large jaws
- abdomen yellow to olive green, with clear cardiac mark. Cephalothorax often more dark coloured, sometimes red
- yellow legs, with frontpair being the longest.
Looks similar to:
Cheiracanthium virescens: this species lives mainly in heathland and will almost never occur near or in houses. Certain identification only through using a stereomicroscope.
Size:
♀: 6-11 mm
♂: 6-9 mm
When?
♀: May till December
♂: May till December
