Peristaltic waves down abdomen of tiny male mayfly

[rjlittlefield]

When I was working with the tiny mayflies pictured here and here, I noticed that the abdomen of the males is unusual also. The central portion of it is almost transparent and gives the distinct impression of being hollow, as in filled with air! There are continuous peristaltic waves visible on essentially the entire circumference of the abdomen, progressing from thorax toward tail. Along the dorsal midline, there appears to be a single "vein", much smaller in diameter and appearing dark, that has waves progressing from tail to thorax. The overall impression is that fluid is being transported tailward along the inside shell of the abdomen, with a return flow through the dorsal vein. I have no idea whether this is what's actually going on, but that's sure what it looks like!

Here is a small animated gif that I hope gives the general idea. It's essentially a cropped clip of 10 frames from the middle of the video, running just a bit slower than actual speed.



A full size, natural speed video can be found here. This is in QuickTime format (.mov file), and you'll need QuickTime 7 software to play it. (There's a free download from http://www.apple.com/quicktime/win.html [for Windows] or http://www.apple.com/quicktime/mac.html [for Mac]).

By the way, the abdomens of the females were not unusual in any way that I could tell. Their coverings appeared completely opaque and I could not see any trace of the waves that were so obvious in the males.

--Rik

Bausch & Lomb StereoZoom 4 (circa 1970) at 45X, Canon SD700 IS held to eyepiece. Video edited for web using QuickTime Pro 7.1 on Windows XP, H.264 codec at 1024K bits/sec .

[Thomas Ashcraft]

Rik, totally fascinating. Plus the eye pics........wow.....this is a wild and beautiful planet that we're on. - Tom

[Ken Ramos]

That's some pretty good vidio there Rik! You didn't have anything to do with that "Snakes on a Plane" thing did ya? Naw, just kidd'n ya. You did good on that vidio. I have often watched the same thing in aquatic worms and such but I never knew the correct terminology for such action until now. Pretty interesting and thanks for the Quick Time link. I had Quick Time already but not the newest version, so I had to do the download. So now I am at least up to date on that freeware.

[rjlittlefield]

this is a wild and beautiful planet that we're on.

Yeah, isn't it, though?

And what's getting better and better is our collective ability to capture really neat stuff and share it with each other. I can remember way back before the Web...but I try not to!

By the way, I really ought to mention that "continuous" was an overstatement. In fact, the waves appeared to be continuous mainly when the beast didn't have anything else to do. When I would bother it, say to tickle it into repositioning a leg, the waves would stop for a few seconds, then start up again. Perhaps it's a way of distributing something important, like oxygen?

--Rik