Tag Archives: soda

DIY mosquito trap using a plastic soda bottle

Here are instructions for building an indoor mosquito trap using a 2-liter plastic soda bottle. All you do is add some bait (honey, fruit, juice, sugar water, or some nectar-containing flowers) and place in a dark corner of the room. It works because mosquitoes seek out sugar, which they require to fuel themselves. Once inside the bottle they can’t get out.

The above instructions are a modification of a Taiwanese science-fair project that eventually went viral. The differences between the original instructions and mine are that (1) I don’t recommend adding dry active yeast, (2) I suggest sugar sources other than granulated sugar, and (3) I don’t wrap trap in black paper. The omission of yeast is because I don’t think the generation of carbon dioxide is necessary to attract mosquitoes to sugar. In fact, adding yeast likely reduces the attractiveness and causes the trap to fail faster.

The critical part of the original instructions is to deploy the device on the floor in a corner of a room. This is because mosquitoes love to hang out in corners — they are dark and relatively free of desiccating drafts.

Tips

  1. The original instructions suggest 50 g (~1/2 cup) sugar and 200 mL (~1 cup) water but the ratio probably doesn’t matter at all. Brown sugar is likely better than granulated (white) sugar because it has more impurities (some of which are volatile). A drop of rose water might make the sugar mixture more attractive.
  2. Make traps with different types of bait to see which ones are most attractive to the species that are local. Anopheles coluzzii, for example, seems to prefer papaya and banana juice over mango juice (Nignan et al. 2020). Other species might prefer oranges. Or, perhaps, durian.
  3. Replace your bait when it stops attracting mosquitoes. Perhaps every four days if you use fruit (Meza et al. 2020).
  4. If you use flowers, opt for ones that have nectar (if you know) and are light-colored. Or stick a small potted orchid inside the bottle — their blooms last for weeks.
  5. If you happen to have a plant with extrafloral nectaries, that’s a great bait that will likely last for a long time (when you’re on vacation, for example). Try a bunch of wild cherry leaves, for example.

Why it works

Mosquitoes are famous for sucking blood, but like many insects they spend most of their lives quietly ingesting sugar from flowers and rotting fruit. For example, here are some mosquitoes nectaring in the middle of the day:

So when mosquitoes find themselves trapped inside, they will zero in on whatever you have on the countertops — fruit, puddles of syrup, cut flowers, or even a dirty sponge. I don’t have photographs of mosquitoes eating fruit inside but Justin Yoshida (Thailand) does: on jackfruit, on apple slices, and on eggplant. Mosquitoes indoors are likely not especially picky about fruit type because the option is starving to death. Mosquitoes even fall into juice containers and die, apparently, as one restaurant discovered.

In case you’re skeptical that these traps can actually work, here’s a video by somebody who followed the original (science fair) directions and killed 9-10 mosquitoes in 24 hours:

Why it won’t work outside

Don’t bother using these traps outside (the recommendation of the viral versions). Mosquitoes prefer natural sources of sugar so they will likely ignore anything inside a bottle, regardless of how delectable you think the concoction is. The exception would be if you live in a desert and there are no plants near your house.

The traps will also not work in rooms full of flowering plants or decomposing fruit. Similarly, if your kids spill juice and soda everywhere, the traps won’t work.

Adding toxins to the mix

If you have a house free of small kids and meddlesome pets, you can add bit of boric acid to the solution to create an attractive toxic sugar bait (ATSB) station. Then, when mosquitoes ingest the fluid they will die even if they manage to escape the trap (it can happen). In fact, once you have a toxin in the fluid you can and should just get rid of the funnel part of the trap — its presence is likely a barrier to some mosquitoes even though it’s relatively wide (~2 cm). Instead, cut a 3 cm hole in the side and keep the cap on the bottle. Note that because these devices are indoors you don’t need to worry about the boric acid (or whatever) poisoning the pollinators in your yard.

The above is nicely explained by Andy Lee Graham:

One perk of adding boric acid is that fermentation will likely be slowed down, extending the life of your fruit juice. Note that fermentation will occur even though you haven’t added any yeast. Fungal spores are present everywhere.

© 2020 COLIN PURRINGTON

Teaching kids about sugar content of beverages

Teaching kids about the sugar content of common drinks should be a requirement in kindergarten or first grade. Here’s one way: have the class construct a display for the hallway or classroom wall that visually shows how much sugar is hidden in common beverages. Like this:

Ideally, also include sweetened milk, apple juice, orange juice, and Gatorade.

Poster titles matter, too. “Rethink your drink” is a popular title (it rhymes) but is bland and doesn’t suggest that drinking less sugar is the ideal. “Avoid cavities by avoiding sugary drinks” or “Don’t drink dessert all day” might be more engaging and informative.

This project would fit in perfectly with most state standards (for example, see page 10 in Health Education Content Standards for California Public Schools). And because it includes numbers (of teaspoons), teachers can use the poster content to visually drive discussions about addition and subtraction. If this poster was done in a fun way, the experience might vaccinate kids against over-consumption of sugary drinks for the remainder of their lives.

If you want some background information relevant to lesson plans on sugar for K-3 levels, here are some resources from BrainPOP. You can pitch the poster completely in terms of dental health. If you are brave and tenured, make the point that drinking sugary beverages causes kids to consume more calories than they expend.

Here are some examples I’ve collected onto a Pinterest board:

Pinterest board Educating kindergartners about sugary drinks on Pinterest.