Weird behaviour of these Drosophila PUPehhhh!

Weird behaviour of these Drosophila PUPehhhh!

Hello everyone!
Some people who know me personally might be wondering that why has a Moina guy (my model organism being that) is writing a post on Drosophila!

So the story traces back to 14 January 2020, Wednesday.
I was there at CUBE HBCSE, Mumbai, just taking a look at the media bottles containing flies when I came across this bottle which had the flies from the Native which means that these flies were trapped from nature.

The flies which I have seen in the lab show two different Geotactic behaviours.
Geotaxis means the motion of the organism in response to the force of gravity.
One is Positive Geotaxis i.e. the flies stay on the ground rather I must say on the media going along the course of gravity.
And the other being Negative Geotaxis which means the flies are found to be on the cotton plug or on the walls of the media bottle which shows that these flies oppose gravity.
And the most common behaviour exhibited by the Native flies is Negative Geotaxis.

So the thing which astonished me as you can see in this bottle is that these were Native flies showing Positive Geotaxis!!
Bottle Details:
Media Date: 28 Dec 2019
Transfer Date: 07 Jan 2020
Bottle name: H2 SL8

Video credits: @Lydia

The bottle on the left (Control): Standard CsBz Drosophila melanogaster flies
The bottle on the right: Native Single Line
Their geotactic behaviour is visible in the above videos

Ok ok
I’m not fooling you guys! :grimacing:

How can I say that these flies are positively geotactic as there are not much flies visible inside (except 2 which I had seen)??

  1. The pupae which are normally seen to be on the walls of the bottle were now dug inside the media!
    The walls were totally clean!
    Unlike the Indians, these pupae must have followed our Honourable PM Modi’s Swatch Bharat Mission! :smile:
  2. Again, we come on to the pupae, their colour was dark and they had long antennae.
    Yes, the pupal antennae were unusually long.
    Close up

Image credits: @Lydia

  1. When I took a normal Native Single Line Flies bottle as control and then compared them with these, I found their eye colour to be more catchy!! (I forgot to take a photo of the eye of the CsBz fly :grimacing:)
    Catchy in the sense, darker in the colour.

    Image Credits: @Lydia

We (@Lydia, @KiranyadavR Ma’am, @yash_sheregare, @Arunan Sir and I) have used the standard CsBz flies as the control mainly.

Image credits: @Lydia

In this, we can clearly see the difference in the size of the antennae and the way in which they are dug inside!

Video credits: @drishtantmkawale
The bottle on 14 January 2020

Video credits: @Lydia
The bottle on 22 January 2020

Video credits: @yash_sheregare
The new media bottle with same flies dated 24 January 2020

Media Date: 18 Jan 2020
Transfer Date: 21 Jan 2020
Bottle name: H3 SL8
Transferred from bottle H2
Transferred by @Lydia

I’ll attach more photos and videos of the same!

Till then, you guys have the responsibility of contributing!
@Arunan Sir, @Lydia, @KiranyadavR Ma’am, @Isha_23, @AditiKale, @TheBN, @yash_sheregare, @hellboy and others CUBists too!


Great write up @drishtantmkawale!
But, do Pupae have antennae? If so what does it do with the antennae?!!

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Pupae do have antennae, I have a photo of the same.

If we talk in general, antennae are used for sensing the environment, sensing the food and predators.

But @Arunan Sir, your question is legit!
Pupae, who are sessile or immotile, why do they need antennae??

Even if something approaches them, they won’t be able to react to them.

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The antennae seen in native Single line pupae are structure which is actually SPIRACLES

Spiracles are said to be breathing apparatus or openings through which air/gases enter inside the pupae/larvae.


Can you share a reference depicting the spiracles of the fruit fly larvae??
And a labelled diagram/micrograph would be great!!

And are these Spiracles the characteristic feature of the larva/pupa?

Actually I m not able to upload the picture and refrence …

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This is from a research paper from University of London, talks about the post embryonic development of tracheal system of Drosophila melanogaster.
One of the pictures from the paper shows those antennae like structures which is actually the Spiracle
Spiracles are said to be breathing apparatus or openings through which air/gases enter inside the pupae/larvae.

Asked to share by @Isha_23

566944751e3b925114940bfe79dc33132e27 (1).pdf (3.1 MB)


@yash_sheregare @Lydia @KiranyadavR
Looking for current happenings of this peculiar case of fruit flies!!
It seems very interesting!!
Please update us with the photos and videos of the bottles, behaviour of the flies!!

If that was the case then these spiracle like structures should be seen on the pupa of every species!!!
But then I’m seeing such type of structure for the first time… :hushed:

According to the reference sent by @Isha_23 this is the structure of the pupa!

And if the thing is that these spiracles are seen throughout every species, then these structures are different…or may be that these are spiracles but then an elongated one!!

What do you say @Isha_23 @drishtantmkawale @Arunan

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I agree to you totally.

So you mean to say that these Spiracles may be present in every species, but they differ in size in different species?

This may/may not be true
But, after looking at the above photo, the CsBz pupa has some elongated structure coming out through its anterior part.
Are those spiracles too?

What do you think?
@Arunan Sir, @Isha_23, @yash_sheregare, @KiranyadavR and @Lydia

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Why do they need Spiracles?

I’ll share my hypothesis…
As per some reference given in one of the posts above, Spiracles are required for breathing and other gaseous exchange.

If this is the case, then all the fruit fly pupa should have same sized spiracles!!
Isn’t it?
Because ultimately, they would be giving rise to fruit flies only right?

This, I feel to be somewhat sceptic
Because, all the pupae which I have seen till now be it CsBz, Native P-Geo and Native N-Geo, give rise to flies initially, but the difference is just of the Physiology!! i.e. their working, their behaviour!!
Is it not?

We see,
The CsBz as well as the Native N-Geo, do not follow the Swachh Bharat Abhiyaan i.e., the walls of the media bottles of these flies are not clean, majority of the pupae are lined up on the walls!
Whereas, Native P-Geo (this bottle of ours) pupae are dug into the media itself!!

So, here comes the main point
I feel that because these flies are Positively Geotactic, their pupae too would be positively geotactic i.e. would be dug inside the media and as they are inside the media, they won’t be able to respire properly with small or normal spiracles, because of which they have evolved to grow unusually long spiracles which would help in proper respiration!!

What do you guys think of this?
@Arunan Sir, @KiranyadavR Ma’am, @yash_sheregare, @AditiKale, @Isha_23 and @Lydia

Please post your thinking about my hypothesis as well as your hypothesis!!

This is getting me excited!


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A really good hypothesis!!
Could be true!!
Spiracles being elongated in positively geotactic flies is really interesting and that’s what we saw in the bottle in which the pupae are in the media itself with none of them on the walls of the media bottle…

If this is the case then the same kind of pupa must be seen in the NS-PGeo flies which was discovered by the girls of Bhavans college!!

So now we need to look for the pupa of the NS-PGeo flies too…
If that also turns out to be the same then our hypothesis would be true!! :ok_hand:


Do we have any archives of the Bhavans College discovery??
It would have been great!!