I have a bad feeling about running out of photos, so now is the time to send them in!
Today we have the second part of Mark Sturtevant’s February 4 post on a spider that lives on water lilies and eats fish. Have a look at the earlier post first, then this one. Mark’s notes are indented, and you can enlarge the photos by clicking on them.
I had recently introduced the six-spotted fishing spider (Dolomedes triton). This species is widespread, and can be found on floating vegetation on lakes and ponds or on river areas with minimal current. From there they will hunt a variety of prey, including small fish. This will be a special post since it is that latter talent that you will see today.
I had brought home a fishing spider, and she was kept for a time in a glass-bottomed aquarium with water and some lily pads. Here she is again. For scale, her leg span was a bit over 2 inches. They do get larger.
The aquarium was put in my backyard for a time, and I could park myself underneath it to photograph activities from below. One tries not to imagine what the neighbors were thinking. Minnows (fishing spider food) were introduced, and I really had no idea if she would even go hunting for one. But from time to time she would extend her legs out onto the water. As I understand it, this is how they monitor for moving prey below, so that was encouraging.
By the way, all of these pictures from the underside were extensively processed since I had put a screen cover over the aquarium to keep her inside while I was directly below. The screen was plainly visible in the pictures, though, so it had to be digitally removed. That was a lot of work!
Anyway, it took a little while, but then something started to happen. At this point I was freaking out!
The actual attack was very fast, and these are among the few pictures that I have of it. What I saw was that the spider strode out onto the water, and suddenly “clawed down” to gather up the fish before retreating quickly back to the lily pad.
The shadow tells the tale.
Here she is again up top. The photographs were taken through glass which was by now rather steamy with the summer heat, and so the pictures required some de-hazing treatments in post-processing to rescue them.
She was deftly turning her prey over and over with her chelicerae and pedipalps, working in the venom. In just a few minutes the tissue dissolving effect of spider venom was very obvious.
Fishing spider hunting has been captured in video. Here are two examples. They really seem to go after fish! [JAC: don’t miss these videos!]
Thanks for looking!