Wednesday, January 20, 2016

Mosquitoes for Science Projects in Schools

The chikungunya outbreak and now the threat of Zika in Jamaica, and the comments about mosquitoes by callers to talk-shows made me aware that much of the ignorance exposed could be addressed by students doing science projects on mosquitoes, with primary research in addition to research on the internet.

There are more than 3,000 species of mosquito world-wide and over 50 in Jamaica. The identification of species is highly technical and carried out by a limited number of persons. However, at the primary school level, children can observe and classify a few species.
Male Aedes with
feathery antennae
For example, all children would be familiar with the Aedes aegypti, which is active during the day, has white stripes on its legs, and breeds in small amounts of water. Other children will be familiar with species which breed in swamps and swarm at dusk, and are bigger than Aedes. The mosquito which transmits malaria, Anopheles, is longer and thinner and rests with its two hind legs in mid- air. Perhaps children are also able to detect a difference in the sounds made by these mosquitoes. It should be pointed out that, although there are some disease carrying species, mosquitoes serve useful purposes as pollinators, as food for bats (who are pollinators and aid in seed dispersal), as food for frogs, lizards and birds, and in their larval stages as food for fish and larval amphibians. Research on mosquitoes is carried out at the Windsor Research Centre in the Cockpit Country.

In the USA, much research is carried out on mosquitoes and suggestions for school projects are described on Clark University’s website.
 The following projects are suitable for biology students taking external exams at end of Grade 11 and higher. They require patience and persistence. It would be helpful is hand lenses and binocular microscopes were available.
A project could proceed as follows :

1.               choose an investigation

2.               conduct background research

3.               list materials needed

4.               list steps involved

5.               estimate the time involved

6.               set up the investigation

7.               collect and record data

8.               analyse data and draw conclusions

9.               present data to the class or school

Aedes  - male to left,
female in center

1.               To investigate the life cycle of Aedes aegypti.
2.               Background research: Reading.
3. Materials: jar containing water with a piece of dead leaf (about 1 cm sq. ) in it/
4.               Steps: Place the jar in places frequented by mosquitoes, and observe daily. When eggs are seen inside the jar, just above the water line, add water to cover the eggs. Take the jar to where they can be observed easily (out of the sun).

5.               Time: 7 to 10 days.

6.               Set up experiment.

7.               Record when the eggs hatch and when the larvae moult. When the larvae become pupae (comma-shaped), cover the jar, to prevent adult mosquitoes escaping. A hand lens would be useful to observe the eggs and the young larvae.

8.               Analyze findings: Did observations correspond with background research?

9.               Present findings to the class.

Suggestions for other projects:

1.     Do Aedes mosquitoes show preferences for

a)     Jars set up in the shade or in the sun?

b)     Jars with dead leaves in them or without dead leaves?

c)     Water with or without food coloring? (use different colors).

2.     What attracts Aedes mosquitoes to people? If students let out the mosquitoes from the above experiments in a fish tank with a tightly fitting mesh cover, they could try the following, being careful not to let out the mosquitoes

a)     Temperature – fill some balloons with warm and others with cold water.

b)     Color – use different colored balloons.

c)     Gases – carbon dioxide from fermentation using yeast; oxygen from hydrogen peroxide.

3.     Survey of persons who had chikungunya. Each child can conduct a survey in their community. Did everyone in the household catch it? Make a map showing where these persons are located. Do they believe that ChikV is transmitted by mosquitoes? Analyze arguments for and against this.
4. What is the effectiveness of different mosquito repellants? Design an experiment to find out.

             For primary school children, a more straightforward project would be to investigate where mosquitoes breed, by searching for mosquito larvae in discarded containers and old tyres. The larvae are most likely to be the final stage before they become pupae. These breeding sites should be destroyed after collecting some of the larvae.These can be put in a glass jar in order to observe when they become pupae and then adults. The jars should be  covered to prevent the adults from escaping. How they could be disposed of is a topic for discussion.