Southern black widow

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