Fly mouthparts - a different interpretation

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

Moderators: Pau, rjlittlefield, ChrisR, Chris S.

NikonUser
Posts: 2634
Joined: Thu Sep 04, 2008 2:03 am
Location: southern New Brunswick, Canada

Fly mouthparts - a different interpretation

Post by NikonUser »

I have been trying to work out the structures in Rik's and Dave's fly mouthparts.
Below is the inflated labellum of a Blow Fly (a large bluebottle - Calliphora vomitoria), how it would look when the fly is feeding.
Note that the so-called "prestomal teeth" in Rik's and Dave's images appear to be plates supporting the pseudotracheae, shown very well in Dave's images. I suspect they are not teeth in that they are not used to rasp off food particles.
The true prestomal teeth appear to be fewer smaller cone-shaped structures much closer to the oral opening and shown in my Micscape article.
Image
NU12016
NU.
student of entomology
Quote – Holmes on ‘Entomology’
” I suppose you are an entomologist ? “
” Not quite so ambitious as that, sir. I should like to put my eyes on the individual entitled to that name.
No man can be truly called an entomologist,
sir; the subject is too vast for any single human intelligence to grasp.”
Oliver Wendell Holmes, Sr
The Poet at the Breakfast Table.

Nikon camera, lenses and objectives
Olympus microscope and objectives

rjlittlefield
Site Admin
Posts: 21277
Joined: Tue Aug 01, 2006 8:34 am
Location: Richland, Washington State, USA
Contact:

Post by rjlittlefield »

A wonderful image!

But I'm suspecting a difference of anatomy between the fly shown here and the ones shown by me, Graham, and in B. Thompson Lowne's book.

In the image shown here and in your Micscape article Fig.4, the teeth are short, squat, and show no signs of forking at their tips.

In contrast, in the ones illustrated by myself, Graham, and Lowne the teeth are longer and clearly forked, and I don't see any short squat ones like you have.

A difference of anatomy prompted by different preferred foods, perhaps?

--Rik

Cactusdave
Posts: 1631
Joined: Tue Jun 09, 2009 12:40 pm
Location: Bromley, Kent, UK

Post by Cactusdave »

Firstly I'm certainly no expert in the interpretation of fly mouthparts and would defer to anyone who is. Your image is very beautiful, but to a non-expert it is difficult to relate it to Rik's intact fly and my very different flattened preparation.

Looking at the slide I used, Topping, an English mounter would certainly have mounted a Calliphora, probably either Calliphora vomitoria or Calliphora erythrocephala (now called Calliphora vicina I believe). Lownes' monograph on the blowfly refers specifically to Calliphora erythrocephala and for mounted material he is likely to have been working with slides like the one I used, as his monograph is contemporary with the period at which the Toppings, father and son were preparing their mounts for sale. My images with the X25 objective closely resemble Lowne's illustration Fig. 31 on page 145 of his monograph which shows 'prestomal teeth' lying in the same relation to what he calls a 'pseudotracheal vessel' in a diagram that is obviously drawn from a flattened mount. What any of this would look like in an intact fly or what the actual function of Lowne's 'prestomal teeth' are, is beyond my competence.

By the way Rik, have I mysteriously morphed into Graham (Matthews)? I don't know which of us should feel more flattered. :lol:

David
Leitz Ortholux 1, Zeiss standard, Nikon Diaphot inverted, Canon photographic gear

rjlittlefield
Site Admin
Posts: 21277
Joined: Tue Aug 01, 2006 8:34 am
Location: Richland, Washington State, USA
Contact:

Post by rjlittlefield »

Cactusdave wrote:By the way Rik, have I mysteriously morphed into Graham (Matthews)? I don't know which of us should feel more flattered. :lol:
OK, now that's a spectacular brainfart! I have no idea why my brain spit out "Graham" instead of "Cactusdave" or "David". You guys are all so high in my pantheon of heroes that it's easy to get confused, but still, that one's pretty extreme! I'm torn between editing my post and letting it stand as a monument to failed fact-checking. Think I'll go with "monument" to keep the thread intact.

--Rik

rjlittlefield
Site Admin
Posts: 21277
Joined: Tue Aug 01, 2006 8:34 am
Location: Richland, Washington State, USA
Contact:

Re: Fly mouthparts - a different interpretation

Post by rjlittlefield »

NikonUser wrote:Below is the inflated labellum of a Blow Fly (a large bluebottle - Calliphora vomitoria), how it would look when the fly is feeding.
I'm struck by the apparent absence of "squashing" in this image. Can you tell us in some detail how the specimen was prepared and photographed??

--Rik

NikonUser
Posts: 2634
Joined: Thu Sep 04, 2008 2:03 am
Location: southern New Brunswick, Canada

Post by NikonUser »

Hi Guys, all 3 of you!

In neither of your images are you showing the true prestomal teeth (my interpretation). Rik's images are distorted due to drying. Dave's are flattened.
Mine is a truly 3-dimensional view from the ventral side. You are looking from the lower horizontal surface, vertically up to the dorsal surface.
The 2 labeled ridges are vertical and are formed of those double-pointed plates; their function is to hold open or support the pseudotrachea.
I do not see any true prostomal teeth in any of your images.
NU.
student of entomology
Quote – Holmes on ‘Entomology’
” I suppose you are an entomologist ? “
” Not quite so ambitious as that, sir. I should like to put my eyes on the individual entitled to that name.
No man can be truly called an entomologist,
sir; the subject is too vast for any single human intelligence to grasp.”
Oliver Wendell Holmes, Sr
The Poet at the Breakfast Table.

Nikon camera, lenses and objectives
Olympus microscope and objectives

Planapo
Posts: 1533
Joined: Tue Nov 07, 2006 2:33 am
Location: Germany, in the United States of Europe

Post by Planapo »

On the right side, in the image shown above in this thread, I think I can see bifurcation on the tips of theses structures, similar to the ones in your pictures, Rik.

There seem indeed to be differences in the length of the (partly) bifurcated structures of the different proboscides shown.

But at this time to me the function that I can see in Tony's interpretation is the one that would make sense for all the proboscides shown in this discussion:
Functioning like spokes (cf. spokes of an umbrella) that prevent the central edges of the right and left labellum from beeing sucked towards the central stomatal orifice and thus blocking this opening when the fly is imbibing liquid, i. e. creating a partial vacuum.
Looking at David's photos and the photo above I can well imagine how the bifurcated tips of the "spokes" "lock in" the rings of the pseudotracheae.

I would have more difficulties to understand how these bifurcated structures should work as teeth (analogously to a snail's radula?), especially when they are longish and articulated at their base.

Probably it would be helpful to see in what position the bifurcated structures are in your species of fly, Rik, when the proboscis is in functional mode, i.e. is inflated.

Tony, did you photograph this proboscis here submerged in liquid (like Ringer's solution) to keep it inflated?

Anyway, fascinating how complex theses structures are.

--Betty

NikonUser
Posts: 2634
Joined: Thu Sep 04, 2008 2:03 am
Location: southern New Brunswick, Canada

Post by NikonUser »

I like Betty' explanation.

Below is a similar view but with the labella tilted sideways to better show the supporting plates. These plates are small, taken with a 20x objective.
Image
Image
NU12017 NU12018
NU.
student of entomology
Quote – Holmes on ‘Entomology’
” I suppose you are an entomologist ? “
” Not quite so ambitious as that, sir. I should like to put my eyes on the individual entitled to that name.
No man can be truly called an entomologist,
sir; the subject is too vast for any single human intelligence to grasp.”
Oliver Wendell Holmes, Sr
The Poet at the Breakfast Table.

Nikon camera, lenses and objectives
Olympus microscope and objectives

Cactusdave
Posts: 1631
Joined: Tue Jun 09, 2009 12:40 pm
Location: Bromley, Kent, UK

Post by Cactusdave »

That last crop looks very similar to my image if you allow for flattening.
Leitz Ortholux 1, Zeiss standard, Nikon Diaphot inverted, Canon photographic gear

rjlittlefield
Site Admin
Posts: 21277
Joined: Tue Aug 01, 2006 8:34 am
Location: Richland, Washington State, USA
Contact:

Post by rjlittlefield »

Thanks, this tipped view helps enormously.

I'm still curious about technique. How are you preparing and holding the specimen?

--Rik

NikonUser
Posts: 2634
Joined: Thu Sep 04, 2008 2:03 am
Location: southern New Brunswick, Canada

Post by NikonUser »

You can think of the labella as a tunnel with a hole dorsally. Side tunnels or canals originate on each side, these are the pseudotrachea; they have their own ring-like support structures. The vertical side walls of the main tunnel are supported by sclerotized plates attached to rigid girders dorsally. These plates end in a fork ventrally where they interact and support the start of the lateral canals.

Found this blow fly in my bug freezer, seemed to be in good condition.
Thawed it in water for about 1 hour, then soaked it in 5% KOH for about 6 hours at room temp.
The softened fly's head was removed and washed in several changes of tap water to get rid of the KOH.
Head placed in absolute Isopropyl alcohol (label says 99%) and immediately the mouthparts were inflated using a syringe filled with absolute alcohol.
Repetaed the inflation for about 5 mins. The idea was to inflate the labella and change them from soft and flexible to hard and rigid.
Left the head submerged in alcohol for a few hours and then placed head in cedarwood oil to 'clear' it.
If the labella are not sufficiently rigid when placed in the oil, diffusion currents will collapse everything.

Then photgraphed the head submerged in a pool of oil using a 10x Nikon CF N Plan objective, and then a 20x ELWD Nikon M Plan. No coverglass. Flash, styrofoam cup, ZS PMax.
NU.
student of entomology
Quote – Holmes on ‘Entomology’
” I suppose you are an entomologist ? “
” Not quite so ambitious as that, sir. I should like to put my eyes on the individual entitled to that name.
No man can be truly called an entomologist,
sir; the subject is too vast for any single human intelligence to grasp.”
Oliver Wendell Holmes, Sr
The Poet at the Breakfast Table.

Nikon camera, lenses and objectives
Olympus microscope and objectives

gpmatthews
Posts: 1040
Joined: Thu Aug 03, 2006 10:54 am
Location: Horsham, W. Sussex, UK
Contact:

Post by gpmatthews »

Interesting images and discussion. After Rik's comments(!) I felt obliged to have a look myself. Unfortunately, not as clear a result as I had hoped, but I have posted a stereo pair at http://www.photomacrography.net/forum/v ... 548#103548

The pseudotrachea seem to show OK, anyway...
Graham

Though we lean upon the same balustrade, the colours of the mountain are different.

rjlittlefield
Site Admin
Posts: 21277
Joined: Tue Aug 01, 2006 8:34 am
Location: Richland, Washington State, USA
Contact:

Post by rjlittlefield »

NU, thanks for the recipe.

One quick question: I have no KOH handy, is there a way to substitute NaOH instead?

--Rik

Pau
Site Admin
Posts: 5317
Joined: Wed Jan 20, 2010 8:57 am
Location: Valencia, Spain

Post by Pau »

NU,
After reading your preparation method, I do apreciate even more your images. This is a lot of patient and skilled work!

(and I had not previously imagined that this proboscis could be a so pupular subjet :shock: )
Pau

NikonUser
Posts: 2634
Joined: Thu Sep 04, 2008 2:03 am
Location: southern New Brunswick, Canada

Post by NikonUser »

Rik: NaOH works fine.
Either KOH or NaOH at about 5-10% is used to soften up insects. They both dissolve all tissues and cannot be used if you want to look at muscle tissue etc.
They have the effect of softening and de-colouring insect cuticle so one has to judge timing depending on the thickness of the cuticle. Normal insect exoskeleton is very tolerant of either and so can be left in the soln for days. However, the membranes on the fly labellae are delicate and so you have to be careful not to leave the head in the soln for very long - too long and the whole lot just disappears. Difficulties arise when you want to make a prep. of an entire head; some parts are heavily sclerotized other parts only lightly so.
No quick fix for experience.
NU.
student of entomology
Quote – Holmes on ‘Entomology’
” I suppose you are an entomologist ? “
” Not quite so ambitious as that, sir. I should like to put my eyes on the individual entitled to that name.
No man can be truly called an entomologist,
sir; the subject is too vast for any single human intelligence to grasp.”
Oliver Wendell Holmes, Sr
The Poet at the Breakfast Table.

Nikon camera, lenses and objectives
Olympus microscope and objectives

Post Reply Previous topicNext topic