Fly Traps

Flying insects can transmit micro organisms that cause diseases either by biting or simply transferring them physically by landing on the host or their food. Removing some of these from the local area should  have some impact on the amount of disease transferred. There is a lot that can be learned from setting up traps and the time and effort involved is minimal. Possibly more importantly the act of catching flies or mosquitoes makes the obtaining of data easy. We can simply count the number caught in a given time. Two identical traps can be set up in different places and hence we can analyse the effect of position. Or different colour/bait/design traps put next to each other. The variables can be dealt with one by one until a most effective solution for design, bait, colour and position is found.

According to the World Health Organisation WHO a crucial element is educating people to understand how best to protect themselves from these diseases. Any program on fly traps should first address this. How  the diseases are spread, rather than just – Kill the flies!

Fly Trap

There are many designs for traps. One of the simplest is the water bottle cut in half and turned in on itself.

A suitable bait is put in the bottom and you have a trap



But what makes a good trap? What might happen if we changed:

  1. The size of the trap/hole
  2. The bait
  3. The colour –  opaque or translucent?
  4. The position
  5. The style

We are encouraging communities to collect and share data to enable them to evaluate and produce effective traps.

Mosquito Trap – An extended view 

Plastic bottles are a good place to start – Why do these need to be removed from the environment?

Plastic bottles and bags are one of the scourges of our planet causing huge problems in ecosystems. The physical unsightly nature of plastic bottles and bags washing up on beaches is just the start. There are many areas of the oceans where wind and currents cause greater concentrations to build up for example the Great Pacific Garbage Patch. The effects of plastic and microplastics  are still being documented, but there are no positives. The findings so far are worrying. Many studies suggest suggest hormone disruptive chemicals such as PCBs are absorbed by microplastics increasing their concentration.  These contaminated microplastics are then eaten by zooplankton and enter the food chain. 

There are some initiatives that students may wish to get involved with

Adventure Science is Mapping data of microplastic concentrations in different parts of the world

global plastics

Their Gallatin River project is here 

OceanCleanup is actively removing plastics from the sea  using some very innovative ideas. Could this be done on a small scale using recyclable materials?

Plasticbank  – Aims to remove plastics and enable people to make money  doing so in an innovative way  poverty and plastics 

There are many different levels we can approach this from depending on the level of sophistication of our students (adults or children) We need to get across the idea of how to get valid data and to analyse it.

Making the Mosquito Trap

Simplest Activity: Without guidance this task may be far too open and we may want to start with a possible route through

Students are given  a model trap that is known to work with the instructions on how to make it and what bait to use. The simplest example is of a plastic bottle cut in half and the top half pushed into the base like a funnel

Diagram to follow

Possible Instructions

Firstly find out what the best place to put the trap is. Note: That whatever bait you use , such as fermenting material, will attract mosquitos. So may actually increase the risk of being bitten. Caution shuld be taken to wash hands thoroughly and take care to prevent infections

Take regular readings in each place keeping all other conditions the same. For example counting how many mosquitos have been caught in each area in a 24 hour period. Repeat these readings until a best spot can be determined.

When the best spot has been determined,  start changing the other variables, one at a time, for example :

  • The bait used – Fermenting material or a source of carbon dioxide
  • The style of trap
  • The colour of the trap
  • The temperature of the trap
  • Size of hole in the lid
  • Add an LED bulb?

Sharing of results will help everyone to come up with guidance of the most effective traps in that local area. What works well in one area may not in others but extended trials with shared results will allow models to be honed.

Extending the project

There are huge possibilities to extend the ideas

Research into Mosquitos

If you want to trap something it helps to know your prey so understanding what attracts mosquitos and what is supposed to repel them . I havent checked the information here , but this suggests 10 ways of how to get bitten – including smelly feet – that has been shown to have an impact! This site gives a lot of information on traps and behaviour– Do natural remedies like  citronella work? How might you find out?

Students could look at the lifecycle of mosquitos and the fact that they fill a niche and are useful as pollinators and food for other creatures. Removing any part of a food chain impacts on other parts, total eradication is likely to have a large ecological impact. Also not all species of mosquitoes bite and for those that do it is only the females.

Mosquitos as vectors of diseases such as Zika, Malaria, Dengue Fever and Nile Virus can be explored as well as the effects of these diseases and treatment. Understanding the need to prevent an infected person being bitten again and hence the disease passed on is also of great importance. A high Tech solution to aid this  is a laser system

Other ways of reducing the mosquito population can be explored. A particularly promising example is an ovillanta using old car tyres as a breeding point that can be drained. They have also uploaded a video showing how to make one yourself

Research and test high technology mosquito repelling Apps? They do not look hopeful

How about commercial traps – can any of the principles be replicated with only recycled materials?

What is the point of making these traps?

Note: According to the World Health Organization (WHO), fin order to reduce diseases transmitted by flies four strategies should be implemented:

reducing or eliminating breeding sites for flies,

reducing sources that attract flies from other areas,

preventing contact between flies and disease-causing agents,

protecting food, eating utensils and people from making contact with flies.

These preventive measures should be the first priority. and educating populations about how to implement them. The fly traps are secondary to these and are useful in reducing fly populations in the immediate vicinity.

Equipment Needed for Mosquito traps:

  • Plastic bottle
  • Scissors/knife
  • Paper
  • Bait For attracting mosquitoes a source of carbon dioxide – either yeast and sugar or sodium bicarbonate and vinegar.

Links to Curriculum:


Life cycles

Useful Links:


Care should be taken when cutting the bottles.

The best bait may be rotting food and care must be taken not to cause infection from the bait and trapped flies

Flies may actually be attracted to the traps and that will increase the populations in the immediate vicinity