Spider baby update!

I know I was worried about feeding my spiders — they’re so tiny, 1.2mm long, and fruit flies are huge, maybe 3 times that size — so some of you must have been worried. Also, don’t worry, no photos in this post.

I went in to the lab to feed them this afternoon, and I shouldn’t have been concerned. Every one had fiendish, cunning traps strung across their containers, and when I tossed a fly in, they were on them instantly, wrapping them in silk and biting them and sucking out their succulent juices. I’m used to adults being so voracious, but young Parasteada are usually more passive and clumsy. Steatoda triangulosa seem to emerge from the egg sac with their killer instincts already primed.

One somewhat surprising observation: I was curious how the adults get their distinctive zig-zag stripe on their abdomen. What I’m seeing so far is that the spiderlings emerge with pale abdomens, which then darken up fairly uniformly. Today, in the 5-day-old spiderlings, I saw a set of white spots along their abdomens. It’s possible these spiders don’t have a dark zig-zag stripe at all — they have dark bodies (like other familiar Steatoda species), and then they make light-colored triangles to create the stripes.

I’ll be watching closely over the next few days. I also have another egg sac that is darkening up and will probably spawn another set of babies for me to play with.


  1. Jazzlet says

    No pictures of the younglings? I am disappointed – rather to my surprise.

  2. says

    I posted some on Patreon and Instagram. I’ve got a base of readers here who didn’t sign up to get spiders in their face.

  3. seachange says

    Maybe they are enough larger at hatching since smaller egg clutch. This might make them more able to predate immediately, and for larger prey.

  4. StevoR says

    Is there much contrast between these spiders (& spiders generally) developing in the laboratory with artificial care versus in the wild?

  5. robro says

    Perhaps they don’t get their distinctive zig-zag pattern until they’re old enough to go to the tattoo parlor.