To address my research question, I need to first trap fruit flies and make single lines by catching gravid females and identify Native Drosophila melanogaster amongst the native fruit flies from the environment!
Following are my research objectives
- Immediate objective
To make homemade media for culturing Native Fruit flies.
To create multiple Single Line culture of Native fruit flies by keeping a bait near kitchen garbage using tomato slice/banana peel and catching gravid females and creating Native Single lines. - Short term Objective
To identify native single culture of fruit flies as Native Drosophila Melanogaster by looking at morphological characteristics relevant to Family Drosophilidae, Genus Drosophila and Species melanogaster. - Long term objective
To perform olfactory assay at range of concentrations of IAA (banana essence) using standard CsBz 2nd instar larvae and Native Drosophila melanogaster 2nd instar larvae and compare their olfactory sensitivity to comment on evolutionary changes in terms of fruit odor smelling!
For achieving these objectives, we started making homemade media with different combinations.
Fruits (like banana and tomatoes) were used for making the media.
But then the issue came when we thought of substituting agar as we need our medium in a slightly solid condition.
There were different alternatives that we thought of…cornstarch, maida, rava…
All these ingredients were used at different times in combination with a fruit.
But then, rava gave good results.
Good results, in the sense, it gave a perfect consistency as we required.
We wanted to simulate the same type of nutrients in the ingredients as used in the standard media.
The ingredients of standard cornmeal media gave nutrients like carbohydrates, sugar, proteins, vitamins, minerals etc.
Banana and tomatoes were fruits that provided nutrients like sugar, carbohydrates, proteins.
Rava too has carbohydrates and proteins.
Media was improvised every time we made, step by step…
These are the different media prepared during the lockdown.
1.15/04/2020 – Banana Rava media
2.19/05/2020 – Tomato Rava Sugar media
3.29/05/2020 – Tomato pieces and Banana peels
4.05/05/2020 – Tomato Rava Sugar – Vinegar
5.17/05/2020 – Tomato Rava Sugar – Yeast Granules
6.17/05/2020 – Tomato Rava Sugar – Coconut oil
7.17/05/2020 – Tomato Rava Sugar – Lemon juice
8.18/05/2020 – Vinegar Triplicate Media
1. Banana Rava media (15/04/2020)
• Rava – 2 Table spoon.
• Banana – 1 peeled.
• Hot water – ½ Cup.
Took one spoon Rava
Add some Hot water and mixed it well. Not cook it.
Took a Glass bottle and entered in to the Rava paste at the bottom.
Add some Banana chopped on the Rava.
2. Tomato Rava Sugar media (19/05/2020)
• Rava – 1 table spoon
• Tomato – 1 egg sized
• Sugar – 1 spoon
• Water – 2 spoon water
Took a fry pan, add 1 spoon Rava, added 2 spoon water.
Cooked it low flame 
Added chopped tomato pieces, mix it well.
Added 1 spoon sugar in the mixer. Mixed it well. Off it
Took a Plastic bottle and added the mixture in to the bottle bottom.
Just pressed it using a spoon.
Tomato slices added on the top.
3. Tomato Rava Sugar – Vinegar (05/05/2020)
• 1 Tomato - 1 egg size tomato chopped.
• Rava - 3 Table spoon.
• Water - ~500 ml
• Sugar - 1 Table spoon.
• Vinegar - ~10ml
Take a fry pan
Add ~500 ml water
Add 3 tablespoon rava
Cooked in 5 minutes, a lower flame.
Add chopped tomato pieces, mix it well.
After add 1 spoon sugar in the mixer. Mixed it well.
Cooked and stirred the medium contents on a low flame for another 5 minutes and added another.
Cooked in total 10 minutes. Off flame.
Take a plastic bottle, that bottle is well cleaned and dry bottles.
With the help of spoon, transferred the semisolid Tomato Rava Media into 3 (a, b, c) plastic bottle.
Bottles a and b without the vinegar. (as controls)
Add vinegar (~10ml) in to the ~100ml media bottle. (bottle c).
4. Tomato Rava Sugar – Vinegar/ Yeast Granules/ Coconut oil. (17/05/2020)
• Tomato - 2 egg size tomato chopped.
• Rava - 3 Table spoon.
• Water - ~500 ml
• Sugar - 1 Table spoon.
Take a fry pan
Add ~500 ml water.
Add 3 Tablespoon Rava
Cooked in 10 minutes, a lower flame.
Add chopped tomato pieces grinding it well and that paste add in to the mixture mix it well.
After add 1 spoon sugar in the mixture. Mixed it well.
Cooked and stirred the medium contents on a low flame for another 5 minutes.
Cooked in total 13 minutes. Off flame
Take 3 Glass bottles that bottle is well cleaned and dry bottles
Transfer mixture, with the help of funnel.
Transferred the semisolid Tomato Rava Media into glass bottles
Each Bottles have ~30ml media.
Finally add additional
Bottles (1) Vinegar - ~5ml, (2) Yeast extract - 1 teaspoon, (3) Coconut oil - 5 liquid.
This is how the homemade media preparation is being modified or improvised step by step.
By now, among all the media that we made, the Tomato Rava Sugar + Vinegar medium (TRSV) is the media that gave the best results.
The next aim or objective is to repeat the same media and check whether we get reproducible results.
What do we mean by best results that we got?
See the pictures of the bottle from which we got the best results.
Larvae
Pupae
Adult flies (Gravid flies)
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