Tracking down Gravid Female Fruit flies!

[Ayana_Sudheer]

I’m in search of gravid female fruit flies those that are pregnant and carrying eggs.
2025-05-05T18:30:00Z
To trap them I set up two slices of tomato on a white plate and kept it on the kitchen table.
How to identify pregnant female fruitflies?
Gravid female fruit flies are those that are pregnant or carrying eggs.

Abdomen size and shape- Gravid female fruit flies have a distinctly rounded abdomen, which is larger than that of males or non-gravid females.
Color changes- The abdomen of gravid females may appear darker or more translucent due to the developing eggs.
Egg-laying behavior- Observe fruit flies near a food source or oviposition site. Gravid females will typically search for a suitable place to lay their eggs.

Classification and Identification of Fruit fly Step by Step

There is a large number of living organisms found on the earth. All these organisms show variations in their shape, size, structure, habit, habitat, nutrition, etc. It is difficult to remember the characteristics of all the organisms without their proper arrangement. The classification helps to explain unity in diversity of the organisms. It gives specific and scientific names to the organisms which are accepted universally. It reveals the relationships among various groups of organisms. Th…

6/5/25; 9.30am
Nallalam, Kozhikode
Photo:Ayana

A gravid female spotted at 10.38am

4 fruitflies are observed at 11.28am on 6/5/25. Of them, two (shown in the first photo) look gravid.
10 fruit flies observed on 6/5/25 at 1.04pm!!
Nallalam, Kozhikode

Photo (a) - Male fruitfly.
It is very small in size, last segments of the abdomen are dark coloured.
Photo(b) - It looks pregnant. Belly is swollen.
What do you think? @⁨Theertha Cube⁩ @⁨~Akanksha Joshi⁩ @⁨Cube Seethalakshmi⁩ @⁨Batul Pipewala⁩ @⁨HBCSE Arunan Sir⁩

Randomly spotted a pregnant fruit fly on squeezed lemon peel kept near the kitchen sink. Belly is so white in colour also rounded.
6/5/25
1.13pm
Nallalam, Kozhikode

Look at the fruitfly with white round belly. I can see something pointing out from the tip of the abdomen. What is that? Is it the ovipositor?
video at 1.53pm
6/5/25
@⁨Batul Pipewala⁩ @⁨HBCSE Arunan Sir⁩ @⁨Theertha Cube⁩ @⁨Cube Seethalakshmi⁩ @⁨Akhil Gupta⁩ @⁨Himanshu Sir⁩ @⁨~Akanksha Joshi⁩ @⁨Sakshi Cube⁩ @⁨Enas⁩

6/5/25; 1.53pm
Nallalam, Kozhikode

An interesting discussion followed up in Contexr2Curriculum group!
[06/05, 3:18 pm] Batul Ma’am: If u take this tomato and put it in a medium bottle the eggs and larvae will develop into fruitflies. U can go for a single line culture after u have many flies in the bottle.
This tomato slice is precious.
[06/05, 3:20 pm] ayanasudheer: From a bottle full of flies, will it be difficult to isolate and transfer a single pregnant female to another bottle, ma’am?
[06/05, 3:20 pm] ayanasudheer: I will. Keep this.
[06/05, 3:34 pm] Himanshu Sir: What if some of the other female fruit flies had already given eggs on that tomato before this fly?
Can it be still called single line culture??
[06/05, 3:35 pm] Batul Ma’am: It will be a mixed culture but she will have enough flies to start single line cultures
[06/05, 3:41 pm] Batul Ma’am: I have done the same for Shehre single line culture.I had kept tomato for food preference test.After two days as I had seen two gravid flies on it I kept the tomato slice in a bottle and I had some larvae they formed a mixed culture.This culture I kept in the refrigerator and emptied the flies in a petri dish.From that I selected a gravid female for my single line culture.
[06/05, 3:51 pm] Batul Ma’am: Putting them in the fridge does no harm to the fly.It slows them than you can see the fly moving slowly up into the inverted bottle kept on its mouth and separate.
Alternatively you can try trapping these flies by inverting a wide mouth bottle on this tomato over the gravid fly.Try a couple of times it may fly into the inverted bottle.
As they say the answer my friend is blowing in the wind…
[06/05, 3:56 pm] ayanasudheer: Yes I used to trap flies by inverting the bottle over the fly on the tomato. It is easy to transfer this way.
[06/05, 4:03 pm] ayanasudheer: I trapped three flies in a bottle. And I wanted to isolate a single pregnant female from it. After 3 minutes of refrigeration, I transferred using a brush. I found it very passive. I kept on the bottle wall, but it fell down then slowly climbed up and got stuck. But in my previous attempt, the TRSV media I made was also a problem. It was more of a liquid type and walls were all wet by the medium.
[06/05, 6:16 pm] ayanasudheer: While trapping the pregnant fly, the inverted bottle method is good according to my experience. We can choose the fly we need and directly can be transferred to the bottle without causing any change in the activity of the fly.
While making trsv in my second attempt, I increased the quantity of rava. After adding vinegar, I mixed well and soon transferred to the bottle by using a plastic funnel.