Dear Mr. Marlos:
I have several of these orb weaver spiders around my house that collect the carcasses of their prey and other jetsam and align it neatly in the center of its web. My question is, what is the function of this refuse structure? I can’t figure it out. Attached are some photos.
Yours sincerely,
Mark Kulkis
My Dear Mr. Kulkis,
Your orbweaver goes by the inglorious name of Trashcan Spider, Cyclosa turbinata, and we identified it in that landmark text for local terrestrial Arthropods: Insects of the Los Angeles Basin by Charles Hogue. Hogue states: “The resting place of the female of this spider in its web is distinctive: it is a loose line of thick webbing upon which the female collects an odd assortment of trash, mainly the carcasses of old prey wrapped in defunct cocoons. All of the web, except for the debris string, is dismantled each day, and the old web material is added to the trash pile. The female spider itself is small (doby length about 1/4 in., or 6 mm) and may vary in color from a mixture of gray and white to almost solid black. It has a disproportionately large bulbous abdomen with a prominent rearward protruding bump; the spider’s eyes are on tubercles.” Could you please get a photo of the eyes to add to this posting? Based on Hogue’s description, we presume that the spider is camouflaged among the debris as a means of protection. We also presume that the debris string acts as an anchor for the web which is respun each day.
Dear Mr. Marlos:
Thank you for the elucidation. I will do my best to capture Ms. Trashcan’s eye stalks on film.
Yours etc.
Mark Kulkis
