Education Always

Level: JHS, Basic 7  |  Subject: Integrated Science  |  Strand: Cycles  |  Sub-strand: Life Cycle of Organisms

Curriculum reference: B7.2.2.1 Show the life cycle of the housefly, its effects on humans, and how to reduce them.

1. What is a Life Cycle?

• A life cycle is the series of changes an organism passes through from the time it is born until it becomes an adult and produces young ones of its own.
• Insects such as the housefly, mosquito and butterfly pass through different forms. This is called metamorphosis.
• The housefly has a complete metamorphosis with four stages.

2. Stages in the Life Cycle of the Housefly

Stage	Description	Time (warm weather)
1. Egg	The female lays about 100 to 150 small white eggs in batches in rubbish, animal dung, rotting food or open toilets	About 1 day
2. Larva (maggot)	Whitish worm-like creature without legs. It feeds greedily on the rotting material and grows	3 to 5 days
3. Pupa	The maggot stops feeding, moves to a drier place and forms a hard brown case. Changes into an adult take place inside	3 to 6 days
4. Adult fly	The adult comes out of the case, its wings dry and it flies. It mates and the female lays eggs again	Lives about 2 to 4 weeks

Egg → Larva (maggot) → Pupa → Adult. The whole cycle takes about 7 to 10 days in warm weather, so flies multiply very fast.

3. Where Houseflies Breed

• Refuse dumps and open rubbish bins.
• Animal dung and poorly kept poultry or pig pens.
• Open and dirty latrines and gutters.
• Rotting fruits and uncovered food waste, for example in markets.

4. How the Housefly Harms Humans

• The fly walks on dirt and faeces. Germs stick to its hairy legs and body.
• When it lands on our food, it spreads the germs. It also vomits digestive juices on food to soften it before eating.
• Diseases carried by houseflies: cholera, typhoid fever, dysentery, diarrhoea and trachoma (an eye disease).
• It is also a nuisance. It disturbs us when we are eating or sleeping.

5. How to Reduce the Effects of Houseflies

• Cover all food and drinks.
• Keep refuse in covered bins and dispose of it regularly in proper dumps.
• Use well-built, clean toilets with covers, such as KVIP latrines.
• Keep the surroundings clean and clear gutters so that water does not stand.
• Use window nets, fly traps and sticky paper. Use safe insecticides carefully.
• Wash hands with soap and clean water before eating and after visiting the toilet.
• Wash fruits and vegetables before eating them.

Remember: Houseflies breed in dirt. Keep food covered, refuse bins closed and your environment clean to break the life cycle.

Education Always (education.inspiringalways.com)