Black spiky extruded capsule

Images taken in a controlled environment or with a posed subject. All subject types.

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rjlittlefield
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Black spiky extruded capsule

Post by rjlittlefield »

I'll leave this as a "puzzle piece" for a short while, just because it looks so strange.

Does anybody recognize this structure?

Field width 2 mm.
2022-02-13-21.18.27-ZS-retouched_CC2_smallCrop.jpg

Crossed-eye stereo:
2022-02-15-14.36.26-ZS-stereo_000_crop01_small.jpg

--Rik

Technical: Mitutoyo 10X NA 0.28 objective on Raynox DCR-150, Canon T1i camera (APS-C sensor), illumination by two Jansjo LEDs diffused through white plastic hemisphere. 297 focus steps at 5 microns. 0.3 seconds at ISO 100, using EFSC.

colohank
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Re: Black spiky extruded capsule

Post by colohank »

Maybe a side view of an insect pupa on a leaf?

MarkSturtevant
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Re: Black spiky extruded capsule

Post by MarkSturtevant »

The vertical striations resemble a stacking artifact that is common near a boundary of a stacked picture. But that seems out of place here.
Mark Sturtevant
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rjlittlefield
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Re: Black spiky extruded capsule

Post by rjlittlefield »

colohank wrote:
Wed Feb 16, 2022 8:45 am
Maybe a side view of an insect pupa on a leaf?
Very good! Yes, side view of an insect pupa on a leaf.

Now, what kind of insect, and why is the pupa black?

(Hint: the ID and the color can both be economically significant.)

MarkSturtevant wrote:
Wed Feb 16, 2022 8:47 am
The vertical striations resemble a stacking artifact that is common near a boundary of a stacked picture. But that seems out of place here.
I agree! But no, those are physical. Here is a 100% crop from one of the source images, run through Topaz Sharpen AI:

IMG_13648_100pctCrop.jpg


--Rik

colohank
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Re: Black spiky extruded capsule

Post by colohank »

Glasshouse whitefly, perhaps? The economic significance of its black color is way beyond my pay grade. A lot of whitefly pupae are black.

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Re: Black spiky extruded capsule

Post by MarkSturtevant »

I was just now thinking scale insect, but whitefly is close. It would be weird that a Hemipteran (a hemimetabolous insect) would have a kind of pupal stage, but they do.
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colohank
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Re: Black spiky extruded capsule

Post by colohank »

Here are a couple of shots of Mulberry Whitefly pupae. I've found them on a Hackberry (green leaf) and an Ohio Buckeye (yellow leaf) in my backyard. I wouldn't know a Mulberry Whitefly if I found it in my soup, so I reached out to a number of sources for an ID. My son has a degree in horticulture, and he, in turn, reached out to a former entomology professor at Colorado State University. The professor made the ID.
Attachments
DSG_1911a-2 (Custom).jpg
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rjlittlefield
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Re: Black spiky extruded capsule

Post by rjlittlefield »

Mine are similar to the greenhouse whitefly, though I would be surprised if exactly that species since mine came indoors from outdoor living in an area that freezes hard over the winter.

But the normal immatures of this species are pale greenish, like this:
2022-02-17-11.07.46-ZS-PMax_small.jpg

Cross-eye stereo:
2022-02-17-13.12.26-ZS-stereo_000_cropSmall.jpg

The black ones are special, and there begins a much longer story.

--Rik

colohank
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Re: Black spiky extruded capsule

Post by colohank »

The suspense is killing me. Why are the black pupae special?

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Re: Black spiky extruded capsule

Post by rjlittlefield »

Ah, sorry. I got so distracted investigating stuff that I forgot to post the solution to the puzzle!

The black pupae are parasitized, each one by a single small wasp that looks like this:
IMG_0566_crop.jpg
Total body length of the wasp is 0.8 mm, from tip of abdomen to front of face, excluding wings and antennae.

The small white thing in front of the wasp in this image may be one of the first instar "crawler" larvae of the whiteflies. I did not notice it there when I took this picture, and there's not enough resolution to be sure. (This is an actual-pixels crop from a 1X shot on Canon T1i, APS-C sensor.)

Here is a comparison of pupa exuviae, parasitized versus not:

Crossed-eye stereo:
2022-02-23-17.07.56-ZS-stereo_000_crop1_small.jpg

The wasps are an important biologic control for whiteflies in greenhouses. There is a lot written about them, for example the slide presentation at https://webdoc.agsci.colostate.edu/bspm ... eflies.pdf .

If anybody wants some challenging micro subjects without the experience of "raising" them, you can buy parasitized pupae at quite a few places, for example https://www.arbico-organics.com/product ... e-shipping . (Oddly, they are not available through Amazon today, although they were, a couple of weeks ago.)

--Rik

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Re: Black spiky extruded capsule

Post by Pau »

rjlittlefield wrote:
Wed Feb 23, 2022 6:32 pm
Ah, sorry. I got so distracted investigating stuff that I forgot to post the solution to the puzzle!

The black pupae are parasitized, each one by a single small wasp ...
Very nice story and pictures, but I still can't locate the striated structure shown at your two first pictures
Pau

colohank
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Re: Black spiky extruded capsule

Post by colohank »

Thanks for the explanation.

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Re: Black spiky extruded capsule

Post by rjlittlefield »

Pau wrote:
Thu Feb 24, 2022 4:10 am
Very nice story and pictures, but I still can't locate the striated structure shown at your two first pictures
The striations are part of the "vertical wall" around the perimeter of the pupa. They do not show in the last pictures because that view is looking down onto the top of the pupae. The vertical wall is visible in the green pupa at the center of the group photo (download/file.php?id=6340), but there the striations cannot be seen clearly because of lighting, coloration, and translucency.

I am not completely sure how the pupa forms. I see that the larval forms all have scale-type bodies that lie flat against the leaf. I think that as pupation occurs, the forming pupa greatly increases in volume by swelling away from the leaf surface and forming a new wall perpendicular to the leaf surface, around what was earlier the footprint of the scale. Probably the new wall is not strictly speaking an "extrusion" in the sense of semi-solid material being squeezed through an orifice, but whatever the process is, it ends up giving essentially the same result: the dorsal surface of the pupa looks much as it did in the last scale stage, but the sides of the pupa end up elevated and striated. In the one specimen that I crudely picked apart, the whole interior was filled with goo.

The style of pupa apparently varies a lot between species. https://webdoc.agsci.colostate.edu/bspm ... eflies.pdf , slide 12, notes that the Greenhouse whitefly pupa has these vertical sides, while the Sweetpotato whitefly does not.

--Rik

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