Balloons in pits, brown marmorated stink bug

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

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Balloons in pits, brown marmorated stink bug

Post by rjlittlefield »

For a long time, I've wondered what certain parts of a brown marmorated stink bug (Halyomorpha halys) would look like if we got really close.

Here's a partial answer (stereo pair, crossed-eye). This was shot with a 50X objective on Canon T1i and cropped to a subject area about 0.17 mm wide by 0.30 mm high, so it displays about 700X on a typical monitor:

Image

Backing way out, here's a view with 5X, uncropped so about 4.2 mm by 3.9 mm.

Image

Intermediate, 20X. The stereo pair is of the area near the right side, just below center.

Image

However, the images above can only be part of the story.

I guessed that someplace on the Internet there might be SEM photos of these things, so I did some searching.

Sure enough, I found these: Looking at the last couple of links, it seems that on the specimen imaged in the SEM, the things in pits look like inflated hot air balloons, while in mine they look more like the balloons are mostly deflated except for rigid ribs. A couple of mine, not included in the stereo pair, even look like they've burst so all that's left is the rigid ribs plus a membrane connecting them.

If anybody knows the function of these things, I would be fascinated to hear!

--Rik

Technical info: all images with Mitutoyo M Plan Apo objectives on Raynox DCR-150 tube lens, flash illumination diffused through Kleenex tissue, processed with Zerene Stacker PMax. The stereo pair is synthetic, +-5% = +-6.8 degrees, 121 images at 0.001 mm focus step.

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Stink bug pits

Post by Olympusman »

That first stereo pair is remarkable. I have often thought those pits are what puts the stink in Stink Bug. By the way, it's getting cold here and they are finding their ways into the house, though not as bad as a few years ago.

Mike
Michael Reese Much FRMS EMS Bethlehem, Pennsylvania, USA

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Post by rjlittlefield »

Thanks!

My understanding is that the "stink" part is provided by glands on the underside, between the legs.

https://naldc.nal.usda.gov/download/24813/PDF writes (regarding a different species) that
Adult Cosmopepla bimaculata discharge a volatile secretion from paired ventral metathoric glands (MTG) when disturbed.
...
Insects can selectively discharge from either the right or left gland or both glands simultaneously, can control the amount of fluid ejected, and can resorb the ejected secretion droplet back into the gland reservoir.
My personal guess is that the "balloons in pits" are some sort of sensory organ. But what kind, I have no idea. Any information will be appreciated!

--Rik

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Post by Pau »

Looking at the last couple of links, it seems that on the specimen imaged in the SEM, the things in pits look like inflated hot air balloons, while in mine they look more like the balloons are mostly deflated except for rigid ribs
Very likely the shape when alive is like ballons and this shape is better preserved by their cryo preparation technique than with your air dried specimen, could I be right?
Can you study an alive or just died specimen?
Pau

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Post by rjlittlefield »

Pau wrote:Very likely the shape when alive is like ballons and this shape is better preserved by their cryo preparation technique than with your air dried specimen, could I be right?
Can you study an alive or just died specimen?
Yes, I expect you're right. I look forward to imaging a fresh specimen, but I have no idea when that will be possible because these bugs are still rare where I live.

I was surprised, to say the least, to see the structure of these things. The usual low-mag images, including direct view through my dissecting scope, show only some little white thing at the center of each pit. I was expecting to find something like a short clear cone or bristle. Such a delicate membranous structure as these balloons never occurred to me!

--Rik

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Post by nanometer »

That stereo is awesome!

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Post by Chris S. »

I'm delighted by this thread. Some years back, I shot a 5x stack of a dried-up brown marmorated stinkbug, and saw vase-shaped structures in the pits. As these structures were very small in the 5x image, detail on them was limited, and I wondered if they were really there, or perhaps just some artifact created by my workflow. (For context, I've seen shiny bits of narrowly-lit subjects "bloom" outward when using the DMap stacking method.) I intended to return to this species at higher magnification and more diffuse light for a better look, but had not yet done so.

So bravo, Rik for your wonderful stereo pair displaying these structures in eye-popping detail! So these "vases" truly exist, and are far more interesting than I'd have guessed. The SEM images Rik linked to extend the story markedly.

Brown marmorated stinkbugs are once again invading my home, as they have during the past few autumns. We find them very annoying--they come down our chimneys (which we can't legally block) so we keep a dedicated vacuum cleaner for catching them, and hunt them aggressively throughout the house several times each day. They land on our windows, walls, and counters, in our food and drinks, on our bodies and in our hair--and when disturbed (often, when in human habitation), they emit foul smells. But as Mike also observed, these stinkbugs so far don't seem as prolific as in prior years. One can only hope that some disease or predator has caught up with this invasive species.

I'd also have bet that these intrapit structures were outlets for stink compounds, but Rik's link compellingly suggests otherwise (though as noted, in a different species).

Just now, one of these bugs landed near me, and I quickly dissected the front and rear portions, leaving the legs and everything attached to them with the middle portion. Subjectively, I could smell stinkbug in the legless front and rear portions, but the smell in the central, leg-including portion seemed stronger (though this portion also contained considerably more body mass and surface area). I have no particular takeaway from this quick test, with obvious faults. Can anyone suggest testing improvements? Numerous specimens are likely to be sacrificed in my household over the next few months. Normally we flush them down the toilet, but I'd be delighted to do something more informative with them if it produced knowledge.

An aside, for anyone interested: Occasionally, while sitting at my desk, I've smelled stinkbug stench occurring in waves: Overpowering then absent; overpowering again and then absent again, this pattern repeating for some time. Eventually I found the cause: Outside my open windows, a stinkbug had been caught in a spider's web. When the spider advanced to evenomate the stinkbug, a cloud of stinkbug smell emerged; when the spider backed off to await the effect of its venom, the stinkbug smell dissipated. So the stinkbug apparently reacted to the spider's attack by emitting stink, then ceased to emit stink whenever the spider backed off. In each case, the waves of stink continued until the stinkbug succumbed to the spider, then ceased.

--Chris S.

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insect 'stinks'

Post by NikonUser »

Perhaps the standard text on insect defensive secretiions is:

https://www.amazon.ca/Love-Insects-Thom ... 0674018273

he does discuss stink bugs, no time now to read through it!
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Post by Rikisub »

Amazing shots and very interesting subject!!

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Post by MarkSturtevant »

Beautiful pictures. The structures look to be what are called campaniform sensilla. I did not know they would shrink with air drying. Campaniform sensilla are mechanoreceptors, and here is some information about them: https://en.wikipedia.org/wiki/Campaniform_sensilla They are clearly very numerous on this insect for some reason, but that is good since then they will know when someone is squishing these invasive insects :)

To photograph them in their natural state, you can firmly hold down a live stink bug. It does not have to be this species, since I expect other species would also have these sensilla.
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Post by rjlittlefield »

Mark, thanks for the information.

The article in Wikipedia describes campaniform sensilla as being embedded in the cuticle so as to respond to deformation. The ones they show have a wide base and a shallow dome, in contrast to these balloons which have a narrow base and a huge flexible dome.

So I have to wonder, are they really the same?

Or are these bags maybe more like air movement detectors, serving the same function as hairs but without sticking up to get caught on anything?

In quick search, I ran into https://www.researchgate.net/figure/FIG ... _322361289 which writes that "The lateral aspects of larval cephalic cuticle of oak tasar moth, Antheraea proylei, a hybrid between Antheraea pernyi and Antheraea roylei exhibited the presence of gravity receptors in the form of dorsal campaniform sensilla."

Google search on Halyomorpha campaniform produced notably few hits at all. :(

--Rik

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Post by Sumguy01 »

:smt038 Very nice.
Thanks for sharing.

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Post by svalley »

An excellent set of images Rik!

When I was working at the Oregon Dept of Agriculture I performed the imaging for a research project looking at egg parsitoid wasps in the genus Trissolcus. Trissolcus japonicus ultimately looked like the best bio-control candidate for brown marmorated stink bug, Halyomorpha halys.

Interestingly, Trissolcus japonicus was discovered in Oregon before any planned field releases. DNA comparisons showed that these were not the same strain as the research population.
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Post by MarkSturtevant »

Rik, there is some diversity to the form of any class of sensilla. But as I understand it campaniform sensilla are a dome snugly sitting in a pit. I don't know what they look like if the dome is shriveled. But actually, your reply has prompted me to push a little harder at looking at this things, and I came up with the Basiconic sensilla. These might be what these things are. See here for example: https://www.researchgate.net/figure/a-C ... _255958103
One would need to see the stink bug sensilla without desiccation to know their true form.
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Post by rjlittlefield »

MarkSturtevant wrote:One would need to see the stink bug sensilla without desiccation to know their true form.
For the moment, I think we might assume that the SEM images that I linked earlier show a well preserved state. Those images appear on an instrumentation website. Hot-linking them here for convenience, they look like this:

https://www.quorumtech.com/__assets__/C ... No0005.jpg
Image


https://www.quorumtech.com/__assets__/C ... g%2002.jpg
Image

I sent an information request several days ago to the contact listed for that website, asking for contact info of whoever took the SEM pictures, in hopes that whoever took the picture might know the function. No response yet, though.

As with "campaniform" (Merriam-Webster: "shaped like a bell"), the term "basiconic" (Wiktionary: "having a conical base") superficially seems to refer to just the shape of the structures. But as I scan the literature, the structures to which the terms are applied seem to have more specific functions, campaniform sensilla being strain detectors found in flexible cuticle and basiconic sensilla being chemoreceptors reported on antennae and palps.

Meanwhile, these "balloons in pits" seem most numerous on the dorsal head and thorax, seemingly far from any areas where there would be significant flexing of the cuticle or any particular need for chemical sensing. I can certainly see that the term "basiconic" is a good description of their morphology, but I'm still left wondering what they do.

Looking forward to whatever more information people can provide.

--Rik

Edited to add: newcomers to the forum, please note that this topic continues onto a subsequent page, which can be reached through the "Goto page 1,2, ... Next" links that appear at lower right of each page.
Last edited by rjlittlefield on Mon Nov 11, 2019 12:33 pm, edited 2 times in total.

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