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Public summary: 

You'll have seen some of these fruit flies before: these cool and beautiful little creatures have shown us how genes can be inherited (by following patterns of features like eye colours), and how genes work.

This experiment aims to introduce kids to a wonderful model organism, the Drosophila fruit fly.
Useful information
Kit List: 

Drosophila flies (wild-type, various mutants) in plastic vials with foam/cotton wool bungs. Plastic petri dishes with Drosophila larvae.
Drosphilia flies in petri dishes allows easier viewing under a microscope.


1) What are Drosophila? Often called 'fruit flies', they tend to be found around over-ripe or rotting fruit. We're interested in them because they've been the subject of lots of (mostly genetic) experiments since they're easy to grow in the lab, have a short (~12 day) life cycle and are easy to make mutants which can help us understand biological processes. Have a look at them - see how big they are. Can you identify males and females? (See below) What colour are their eyes (wild type have red eyes).

2) Drosophila development: Provided should be several Petri dishes containing different developmental stages of the fruit fly. Explain to the children the general concept of development (i.e. the process that helps us go from a sperm/egg to a full grown adult) and how it differs from species to species. Next, using the laminated descriptions/photos of the developmental stages (see below), ask the children to put the Petri dishes in the correct order of development. See lower down page for some pictures/descriptions.

3) Identification of Drosophila phenotypes: There will also be several vials of flies with various phenotypes (some of which are listed below…the exact phenotypes we will be given depends on availability during the week of Crash, Bang, Squelch!). Discuss with the kids how mutations in the DNA of the fly results in various fly abnormalities – ask them to look at the flies and try to pick out some of the phenotypes shown on the handout (shown below). You can use this to relate how differences in DNA make humans look different (hair colour, eye colour etc.) and say that we inherit these from our parents.

It may be easier to view the flies if they are in a petri dish so a microscope can be used however it's possible using test tubes.

Risk Assessment
Date risk assesment last checked: 
Wed, 08/01/2020
Risk assesment checked by: 
Matt Worssam
Date risk assesment double checked: 
Sat, 25/01/2020
Risk assesment double-checked by: 
Beatrix Huissoon
Risk Assessment: 

Drosophila fruit flies in plastic tubes + eggs/larvae/pupae in petri dishes. Kids will look at the flies under a light microscope, and at laminated pictures of fly development.

Hazard Risk Likelihood Severity Overall Mitigation Likelihood Severity Overall
Glassware Petri dishes/plastic tubes may be dropped/broken – risk of injury from broken containers. 3 2 6 Ensure that the flies are kept in close range. Ask children to be careful when handling tubes/petri dishes. Use plastic vials (instead of glass) to contain flies if possible.
Call a first aider in the event of cuts. Wash any small cuts with soapy running water. Compress and elevate large cuts.
2 2 4
Electrical equipment Electrical hazard and may become hot and may be touched by children 4 3 12 Switch off microscope between uses if it starts to become hot. In the event of a burn, hold area under cold water for at least ten minutes. Call a first aider.
See separate electrical RA (attached) for other hazards
2 3 6
Drosophila Petri dishes and plastic tubes may be opened - drosophila are non-harmful insects, but it could cause panic/great excitement/silly attempts to inflict the insects on siblings, which can be a safety risk in a crowded place. 4 2 8 Secure the petri dish lids to the petri dishes using tape (stretchy lab tape is fine) so that it is obvious to all that the dishes should not be opened. Demonstrator to keep an eye on all plates.
In the event of an incident, demonstrator must regain the petri dish/vial and diffuse the situation. Call for help if necessary.
1 2 2
This experiment contains mains electrical parts, see separate risk assessment.