Category Archives: Biology

Spartan Mosquito Eradicator

Scientists conclude Spartan Mosquito Eradicators don’t work

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Research conducted in Florida found no evidence that Spartan Mosquito Eradicatiors are effective mosquito-control devices. Below is my reconstruction of the two experiments they conducted. One was in the laboratory, one was outside.

Laboratory experiment

Below is a rough reconstruction of the laboratory experiment they conducted. In each of the cages (BugDorm-2120), 100 male and 100 female tiger mosquitoes (Aedes albopictus) were released, then monitored for mortality at 24, 48, and 72 hours.

Schematic of laboratory experiment based on description in Aryaprema et al. 2020.

Here is a photograph of one of the choice cages:

Below are the cumulative mortality data for the three cages. The Spartan Mosquito Eradicator filled with the provided packet ingredients (treatment) did not result in higher mortality. I.e., there was no evidence the device killed mosquitoes under laboratory conditions.

Field experiment

The researchers also conducted a field experiment using two sites that had large populations of tiger mosquitoes (because of the presence of tires). At each site they deployed five tubes (separated by 4 m), switching whether the tubes were “treatment” or “control” tubes every 2 weeks. A BG-Sentinel trap (without carbon dioxide) was used to quantify mosquito numbers every week.

Schematic of field experiment based on description in Aryaprema et al. 2020.

Below are the weekly numbers of mosquitoes caught in the BG Sentinel traps. Results: there was no evidence that presence of treatment tubes (filled as per company guidelines) reduced the numbers of mosquitoes at the sites.

Conclusions

The scientists concluded that “Both laboratory and field components of our study show that the Spartan Mosquito Eradicator is not effective in reducing abundance of Ae. albopictus.” They speculate that the contents do not attract mosquitoes and that the holes on the device (~3 mm) are too small for mosquitoes to easily reach the fluid inside. They also highlight the need for an experiment to evaluate whether the active ingredient (1% sodium chloride) kills adult mosquitoes. I.e., even if mosquitoes were attracted to Spartan Mosquito Eradicators and could easily get inside, the salt might not be lethal.

Aryaprema, V.S., E. Zeszutko, C. Cunningham, E.I.M. Khater, and R.-D. Xue. 2020. Efficacy of commercial toxic sugar bait station (ATSB) against Aedes albopictus. J. Florida Mosquito Control Association 67: 80-83. PDF

Update: the salt experiment has been conducted. And the result is that salt does not kill mosquitoes.

All of these results are no surprise to anyone. Please see my 2019 review of the Spartan Mosquito Eradicator for details. I also reviewed the Spartan Mosquito Pro Tech, the company’s newest tube. It is just as effective. I.e., they are equally ineffective.

Indoor mosquito trap made from plastic soda bottle

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Here are instructions for building a 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.

DIY plastic bottle mosquito trap
Printable version

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.

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:

Psorophora ferox
Aedes albopictus (Asian tiger mosquito) nectaring on swamp milkweed
Aedes albopictus

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. And here’s a mosquito eating brioche goop at my house:

Asian tiger mosquito

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:

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 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 container. 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:

Anne Barone writes that blackberry wine pairs well with boric acid.

Note that fermentation will occur even though you haven’t added any yeast. Fungal spores are present everywhere.

Commercial, outdoor versions that contain yeast

In the United States the following “yeast and sugar” products are advertised to kill mosquitoes outside: the Spartan Mosquito Eradicator, the Spartan Mosquito Pro Tech, the Sock-It Skeeter, the Donaldson Farms Mosquito Eliminator, the Mosquito XT, the Aion Mosquito Barrier, the Skeeter Hawk Backyard Bait Station, Grandpa Gus’s Mosquito Dynamiter, Tougher Than Tom’s Mosquito TNT, and the Solution X. I’ve reviewed them all here (they don’t work).

© 2021 COLIN PURRINGTON