Raft Spider challenge

[odds]

I spent quite some time this spring trying to learn the habits of the Raft Spiders. They do walk on water, but I wonder if they fear open stretches because I see them run like crazy when there is some distance between plants or rocks they visit.

Alas, I was never able to pull off a low angle shot showing a running Raft Spider surrounded by backlit spray from its feet whipping the water surface. An intense run with visible spray lasts only a few seconds and appears impossible to predict. I am looking for advice or ideas on how I can to pull off that kind of shot. Example images with some explanation would be great.

I attach an image of one of the Raft Spiders I shot after a spectacular run, but it is not the kind of image I'm after.


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Odd S.

[Shadowman]

Nicely captured. have you considered an underwater camera slightly submerged in the water?

[odds]

have you considered an underwater camera slightly submerged in the water?

That would be a step up, or shall we say down, from what I have tried. The problems I faced are more in the realm of being at the right place, pointing the camera in the right direction and trigger the shutter while the action is on. I tried to throw dead flies and mosquitoes on the water hoping a spider would make a run for food, but no. Obviously, the camera must be low and I may have to rig a flash or two, but I got the feeling that I first need to develop some action prediction skills rather than relying on sheer luck.

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Odd S.

[Abitconfused]

Very nice photo. I speculate that this spider’s use of surface tension while still becomes less certain once the tension is displaced through movement. So moving fast may provide some thrust against the surface of the water to offset the loss.

[odds]

...moving fast may provide some thrust against the surface of the water to offset the loss.

Could well be. It looks a bit like a tiny scale take-off run of a swan/goose.

I wonder how I could trigger a run towards my position. Bait like dead flies has not worked. Perhaps a dead fly (dragon fly?) and a tiny buzzer vibrating the water surface can make a difference. I know far too little about spiders, but I think those that catch insects in a web, respond to web vibrations.

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Odd S.

[JohnRostron]

These spiders respond to the movements of insect trapped in the surface film. That is why a dead mozzie evokes no response. Placing a living mosquito onto the surface film is going to be no easy task. Especially if you want to avoid disturbing the spider. Could I suggest you look for an occasion when the mosquitos are emerging from their pupae. That generally creates a few ripples. My other suggestions are to use an infra-red release and to use burst mode. This last would not work with flash, but you can get some pretty powerful led lights now.

John

[odds]

These spiders respond to the movements of insect trapped in the surface film.

Sounds reasonable, and I guess that must be why I mostly find them resting on a leaf, a piece of wood or a rock with at least two feet on the water surface, even while they feed on a catch.

...a dead mozzie evokes no response. Placing a living mosquito onto the surface film is going to be no easy task.

That is what I learned and also why I thought of experimenting with a simple oscillator feeding a piezo-buzzer inside a little float to see if I can make it trigger Raft Spider runs and make things more predictable.

Emerging mosquitos is an idea worth checking out, I will try to be there.

A dead fly or mosquito can, by the way, create other interesting situations. While waiting in vain for Raft Spiders I got to watch grown up Water Striders with and without apprentices dig in and suck their victim empty, like those in the attached image.

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Odd S.

[JohnRostron]

Water striders also respond to vibration. However, unlike the rafting spider, they do quarter the surface and so would encounter a dead fly by accident.

John