Empty Hemiptera Eggs

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Beatsy
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Empty Hemiptera Eggs

Post by Beatsy »

These are the eggs that were parasitised by the tiny wasps. The last two hatched out (very slowly) last week and I noticed the patch of empty egg cases was still there this morning. So I took them in for one last shoot on the studio rail.

10x mitty at 6.3x onto APS-C.
2021-06-28-16.47.07 ZS PMax_DxO_1-.jpg
As is nearly always the case, looking closer revealed a surprise. From previous photos taken in-situ and from examining with a loupe, I thought the eggs were glued directly to the leaf. But higher mag reveals they're actually stood off the surface on little hardened-mucous tripods. Which begs the question, how on earth does a bug just pushing eggs out of it's butt manage to arrange that? Fascinating.

Nearly every time I take a closer look at something, I seem to increase what I don't know more than I increase what I do! At my current rate, I won't know *everything* by Christmas! :D

rjlittlefield
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Re: Empty Hemiptera Eggs

Post by rjlittlefield »

Beatsy wrote:
Mon Jun 28, 2021 10:33 am
... stood off the surface on little hardened-mucous tripods. Which begs the question, how on earth does a bug just pushing eggs out of it's butt manage to arrange that?
Fascinating! I have never looked at a raft of bug eggs like this. Searching some of my old images, I ran across viewtopic.php?t=37359, image #2, which suggests that some of the eggs are glued direct to substrate and some are elevated. I'm wondering if that could be a matter of how the raft as a whole is laid down and warps, before all the adhesive hardens.

As for the "how", I have visions of the beast squirting out a little pad of adhesive, then positioning an egg on top of it. But that's just imagination working. It would take some world-class video to tell for sure.

--Rik

Beatsy
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Re: Empty Hemiptera Eggs

Post by Beatsy »

I have a theory. V1.00...

The eggs and surrounding sticky mucous are held in a sac or tube (or something) that leads to the ovipositor. This is also a tube and is a tight fit for the eggs.

The insect finds a spot, lowers it's ovipositor to the leaf and pushes. A small blob of mucous will come out first, followed by the egg which will be stuck on top of that blob. More mucous will naturally accumulate between the eggs (in a tight tube) because of their rounded ends, but any adhering to the sides of the egg will be scraped/squeezed off and held back by the ovipositor as the egg passes through. It will become part of the blob sitting under the next egg when the cycle repeats.

Back to the blob and egg on the leaf. The mucous blob is sticky enough to hold onto the egg and leaf and viscous enough to maintain it's shape as a flattened blob. The egg is held away from the leaf to some degree (varying from none to a bit).

The mucous begins to dry and shrink, outside first. Before long, the outside of the mucous blob hardens into a thin but stiff truncated conical shell that permanently holds the egg in position. After that, over time, the rest of the mucous dries, shrinks and pulls into strings and bands (on the initial hardened skin) that look tripod-leg-like (although the number of "legs" is actually very variable).

That's it. Does the theory need a major version change, or just a revision? Wotcha think?

rjlittlefield
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Re: Empty Hemiptera Eggs

Post by rjlittlefield »

I don't see anything in your model that explains the apparent total absence of mucous on the tops of the eggs.

Seen in profile, the tops of the eggs appear to be covered in a fine reticular structure that looks totally unlike the dried adhesive.

--Rik

Beatsy
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Re: Empty Hemiptera Eggs

Post by Beatsy »

V1.00 clutches its heart as it falls, mortally wounded, to the floor. Yeah - bit of a flaw that. However...

I'm not quite so sure that the "reticulation" isn't the mucous too. Given how a blob of this sticky-stuff (presumably) dries up, it doesn't take a big stretch to imagine a thin film of of the same drying and naturally "puckering up" into the reticulation pattern seen on the surface. I'm not saying it *is* that, but I believe it could be. If that turns out correct then V1.00 may have a Lazarus moment! :D

Here's a 100% crop of the middle bit of the pic in the first post...
reticulation-pmn.jpg
Edit: now I think about it, the eggs do start out bright green and "mature" over the next 24-48 hours whereupon they go brown and gain the (whitish) reticulated exterior. I don't recall seeing it on fresh eggs (of butterflies and the like). So maybe the eggs are simply coated in goop when they're laid. The rounded ends ensure more goop sticks there for anchorage and it all just dries into a weather-proof coat. The reticulation is simply a natural emergent property - like cracks in dried mud flats etc.

Edit 2: And some circumstantial evidence - mainly because of the accompanying image --> https://hingstssignpost.blogspot.com/20 ... nkles.html

abpho
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Re: Empty Hemiptera Eggs

Post by abpho »

Great job.


The scene from within the Engineer spacecraft from Alien comes to mind.
I'm in Canada! Isn't that weird?

Beatsy
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Re: Empty Hemiptera Eggs

Post by Beatsy »

abpho wrote:
Tue Jun 29, 2021 4:24 pm
Great job.


The scene from within the Engineer spacecraft from Alien comes to mind.
Thanks.

Yeah. I wonder where the set designers get their ideas from... 😁

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