Mosquito head aerodynamics?

leonardturner · Post by **leonardturner** » Fri Nov 01, 2013 3:29 pm

I am almost dissuaded from posting these having just seen Charlie's superb mosquito head from yesterday, but I do have a question. Can anyone tell me the presumed function of the little "brooms" extending from the posterior of the Aedes' head?

Nikon Labophot, 10X CFN Plan Achro, Nikon D3S

40X CFN Plan Achro

Leonard

ChrisR · Post by **ChrisR** » Fri Nov 01, 2013 8:11 pm

No idea, sorry, but a lovely detail.
"40X CFN Plan Achro" - did you make a slide ?

Olympusman · Post by **Olympusman** » Sun Nov 03, 2013 8:51 am

These are the antennae. You can tell a male mosquito from a female because the bristles on the antenna are more complex since they are used to locate a female by her pheromones. It looks like you have a male here.

rjlittlefield · Post by **rjlittlefield** » Sun Nov 03, 2013 9:34 am

To clarify: the antennae are on the front of the head, on the right side of the first image.

I think that Leonard is asking about those small scales on the back of the head, on the left side of the first image.

I do not know their function.

--Rik

leonardturner · Post by **leonardturner** » Sun Nov 03, 2013 11:21 am

Quite right, Rik; I was referring to the back of the head, detailed in the second image. I'm familiar with the antennae and the information on sexual differentiation they provide, but had never noted these scales before (a better term, I think, than my "broom" reference). The notching looks a bit reminiscent of the scales in a butterfly wing.

Thanks to all for your interest and comments.

Leonard

rjlittlefield · Post by **rjlittlefield** » Sun Nov 03, 2013 12:27 pm

leonardturner wrote:The notching looks a bit reminiscent of the scales in a butterfly wing.

Yes, and it looks particularly reminiscent of scales often found at the margins of the wings, such as illustrated by NikonUser HERE. I suspect you're right with that suggestion that aerodynamics are involved.

--Rik

ChrisR · Post by **ChrisR** » Sun Nov 03, 2013 3:25 pm

It's tempting to think of the design of aero cycling helmets, but dragging those antennae through the air must be an overwhelming matter.
http://www.intelligent-triathlon-traini ... elmet.html

leonardturner · Post by **leonardturner** » Sun Nov 03, 2013 3:40 pm

Chris, a very good point. Still, the resemblance to the butterfly/moth scale is uncanny. Perhaps rather than improving airflow their movement provides some sensory input to that small brain.

In answer to your earlier question, I didn't make a slide; just shot the images and discarded the specimen. The stack was run with Zerene.

Leonard

TimmyG · Post by **TimmyG** » Mon Nov 04, 2013 3:20 am

Hi all, just to chip in here. I'm no expert by any means but have been getting into macro recently and enjoying the learning a bit of entomology along the way.

I've just finished reading Wigglesworth's "The Life of Insects" and in one chapter he talks about the sensory organs of insects (in particular flies) and describes how there is a row of hairs along the back of the head to help the fly to understand the position of it's head (which in turn aids it in orienting itself in flight).

IIRC he describes an experiment where they weigh down part of the head and then trim the hairs at the back to see if the fly will compensate etc. Something like that anyway, but I suspect a similar thing is going on here.

I might be off the mark or the understanding may have changed (it's from the 60's I believe) but hope that is interesting to you.

leonardturner · Post by **leonardturner** » Mon Nov 04, 2013 2:04 pm

Thanks--good input.

Leonard

ChrisR · Post by **ChrisR** » Mon Nov 04, 2013 2:12 pm

Leonard - I was wondering about the lack of coverslip - it's sharper than I would have expected..

Tim -

weigh down part of the head and then trim the hairs

small clippers

leonardturner · Post by **leonardturner** » Mon Nov 04, 2013 3:25 pm

Chris--sorry, I misunderstood your question in that I thought you were asking whether I had made a permanent preparation. I shot this stack (61 images) several weeks ago; about that time I was using slides with a central depression--what we used to call "hanging drop" slides, and it is entirely possible that this fellow was so situated with a proper coverslip, but

my dynamic combination of inadequate notes and despicable memory doesn't permit a confident answer. I will try to keep better records--and make better stacks--in the future.

Incidentally, this specimen was one of a number of pupae hatched in the house under a glass dome. In the process of transferring for examination, 3 or 4 escaped. I could only hope they were all males. My wife was not amused.

Leonard