Nematode Worm found in dung

[jimmymac2]

Can anyone identify these worms, or suggest a useful online identification resource? I've tried the Darwin Nematode Key but it doesn't work on either of the family computers. Found in dung by a clump of Pine trees on windy heathland.

[jimmymac2]

And could these be its eggs? I've found two different types.

[Simon Horsnall]

Can you tell what the dung came from? I am assuming it is a ruminant. A photo would help.

I know nothing about nematodes but feel they could be partially if not completely host specific. I also cannot find a nematode as small as this.

If they are something like lungworm, Dictyocaulus sp, then the eggs will not appear in the dung. The adult worm infects the bronchii of the host. The eggs, once laid are coughed up in the sputum and swallowed. These then hatch in the intestine, the larvae being passed in the dung. Equally, they could be a free living species in which case, yes they could be eggs.

Not much of an answer I'm afraid but I think these are probably one of those specialised groups.

[jimmymac2]

At the time the dung was either horse or cow, as lots of animals roam Ashdown Forest, but now it's almost definitely a cow pat as I found an asco on the same pat which specialises in cow dung (and only very rarely appears anywhere else).
Thanks anyway though and I'll keep looking!

[jimmymac2]

Aha! I think I've nailed the species! Dictyocaulus viviparus. See this image: http://www.rvc.ac.uk/review/parasitolog ... _-p-64.jpg

[Simon Horsnall]

But also see:

CelegansGoldsteinLabUNC.jpg

Caenorhabditis elegans is a free-living roundworm found in organic matter. Either way, they are in the 400-500 micron range. In addition, its eggs would be present in the dung (Dictyocaulus viviparus wouldn't, as I stated in my earlier post). Having said that, they may not be eggs or they may be eggs of something else

I really don't think they can be done by matching pictures. I think L3 (which I think this is) larvae will be very difficult, even to key. They appear to be very short on distinctive morphological features.

[jimmymac2]

It must be very small! It is even smaller than I first thought, with the worm I measured, I was using the 10x objective, but was measuring with the 40x calibration! So 36.15 divided by 4 = 9.0375! Perhaps not a nematode at all? Is that possible? Thanks for your help...

[Simon Horsnall]

If you're using a graticule (I assume computer measuring works in the same way) then the image is 4 times smaller so your measured object is 4 times larger (does that make sense?). Therefore a 36.15 micron object with a X40 would be 144 microns with a X10. That would pull us into the realm of sensible, particularly if this is an L1 of a free-living species.

[jimmymac2]

Thanks a lot! I haven't been able to find anything on L1 nematodes, have you?

[Simon Horsnall]

No, but not really looked as they are not my area. Like I said earlier, they look pretty short on distinctive morphological features. In addition, I think most of the literature will concentrate on the commercially important species (Dictyocaulus spp, Meloidogyne spp, Phasmarhabditis hermaphrodita, etc).