Eggs of a Fritillary butterfly (Speyeria), more views added

[rjlittlefield]

This is the egg of a Fritillary butterfly, genus Speyeria. I think this one is S. atlantis, but as I've said before, this group is always troublesome.

This is the first one of these that I've been able to photograph since stacking became practical. It's interesting because I had always thought that the texture was much smoother. Apparently my earlier impressions were gleaned from looking at the eggs only with small aperture lenses that would give me usable DOF in a single frame. This one, of course, was shot with a much wider aperture, giving much better resolution, and now it's obvious that in fact the surface is fairly rough at small scale.

I decided to post this one out as B&W because otherwise it would have been unrelentingly BROWN. The problem is simply the subject. The egg is brown and the butterfly laid it on the inside of a brown paper bag. It's glued on solid, and I couldn't even see a good way to get a different colored background behind it.

Hope you find this one a bit different, at least.

--Rik

Technical: Canon 300D, 10X NA 0.25 microscope objective on 150 mm extension. Dual fiber halogen illuminator with pingpong ball diffuser. 83 frames stacked by HF at 0.00025" focus step.

Edits: to change title

[bill henderson]

This is the stuff I really like. I've been into microscopy since I was 9 yrs old and DOF has always been the problem, from my first Gilbert to my Ultraphot. Ain't stacking software nice,Great photo Rik

[Ken Ramos]

Well I don't stack and that thing looks like a knit watchcap only lighter in color. A great photograph Rik and funny I had not noticed that it was in B&W until you brought it up. See how much I pay attention these days. Funny though...I thought I was the only one who remembered "Gilbert Microscopes," what a clunker! Got one for Christmas one year, after pestering my folks for a scope the whole year before until then.

[Raul G]

Great Photo Rik,
It is almost like cacti.
Do you have a top shot?

[Walter Piorkowski]

Very nice Rik. You comment that the final image did not match the impressions created by an original view due to lack of DOF. Boy I couldn't agree more. Also for me watching the stacked image appear for the first time is akin to the development of the photopaper in the tray.

Walt

[rjlittlefield]

Thanks, guys.

Yes, these sharp-everywhere-you-look images really give you a different view of the subject. And a very pleasant one, I might add!

Caronte, no top shot yet, sorry. But stay tuned...

--Rik

[jaharris1001]

ya know,,, that looks like a cap my grandmother knitted for me for Christmas one year
Very cool image,, very sharp
Jim

[rjlittlefield]

Great Photo Rik,
It is almost like cacti.
Do you have a top shot?

Here is your top shot, Caronte.



This is slightly higher magnification than the earlier one, but that is just due to a tighter crop because the egg is smaller in this view. Same equipment, 97 frame stack spanning 0.020 inches (0.51 mm). Only about half the total height of the egg is in focus here.

--Rik

[Raul G]

Amazing symmetry.
Your image raises very interesting questions.
Like; does Lepidoptera packs their eggs in isometric ways or not?
They might be packed with a divergence angle; a golden angle maybe?

That would be very interesting...

Wonderful pic

[rjlittlefield]

Amazing symmetry.
Your image raises very interesting questions.
Like; does Lepidoptera packs their eggs in isometric ways or not?
They might be packed with a divergence angle; a golden angle maybe?

Caronte, here is some more information for you.



To my eye -- putting on my skeptic's glasses -- there is much more symmetry inferred by the human than is actually present in the eggs.

Certainly there is a general pattern of "big scallops in columns up the sides, with a rosette of smaller scallops at the apex". But even in the single high resolution image posted earlier, I think it is difficult to identify a piece of symmetry that holds very rigorously anywhere. In the montage of eggs, the situation is even worse, with different eggs having (to my eye) significantly different distributions of small and large facets.

Personally (and perhaps oddly, since my formal training is in mathematics), I would find it more interesting to know what is the biological function of the scallops. Scallops are very common in butterfly eggs, but not universal -- some groups like the swallowtails use essentially smooth spheres. It's tempting to say "Oh, the scallops must be for structural stiffening." But these eggs are seldom subjected to any crushing forces where the scallops would matter. At least, it seems that way in casual observation. I am not aware of any careful experiments in this area. A puzzlement.

BTW, in this latest picture, the heads of the developing larvae can be clearly seen as dark blobs within the eggs. They will hatch in a couple of days. The small caterpillars will immediately seek out ground cover in which to hide. In the wild, they wait out the winter in a sort of hibernation, not eating at all until after the spring thaw when the fresh young violet leaves emerge. It seems a precarious existence, but that's the way all the Speyeria work.

I'm glad that you are enjoying the pictures.

--Rik

PS. This is the type of view that I'm used to seeing -- small aperture, generally smooth appearance between the scallops. There's very little trace in these pictures of the fine rough texture captured so clearly by the microscope objective.

Technical: Canon 300D, Olympus 38mm bellows lens at f/8 marked. Single exposures, not stacked.

[Raul G]

Very cool collection

I agree with you that the patterns might emerge from tension phenomena.
But I also believe that underlying every chaotic system lays an ordered one sustaining it.
You must remember the good Voronoi and the relation of his work with the Napoleon theorem.
I don’t think there is much work done in the field of Lepidoptera egg morphogenesis but these great photos are a start.

It seems to me that all the eggs have 24 sides, but it is difficult to say from here.

[rjlittlefield]

It seems to me that all the eggs have 24 sides, but it is difficult to say from here.

Could be -- I can only count reliably in three of these, and they do all end up with 24 at the base. There are fewer columns nearer the apex, and the places where a column divides to make two seems to occur somewhat randomly, but maybe they always end up with 24 columns at the base.

It would be interesting to know the details of how these eggs form. I have no idea what the process is that gives the egg shell its shape.

--Rik