Tag Archives: Florida

Experiment shows Spartan Mosquito Eradicator do not work

Experiments on Spartan Mosquito Eradicators fail to detect efficacy

According to research conducted in Florida, there’s no evidence that Spartan Mosquito Eradicators kill mosquitoes. Here’s the citation:

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

I summarize the two experiments and explore some of the implications, below.

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.

Below are the cumulative mortality data for the three cages. Result: 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

Their overall conclusion: “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. Per unpublished research, a 1% salt solution is, in fact, not lethal to adult mosquitoes.

Implications

The results of the experiments call into question the efficacy claims made by the owners of Spartan Mosquito. For example, the company says on the box that a 95% reduction in mosquitoes will occur within 15 days and will last for three months. The company also prints a graph on the label that indicates almost 99% of mosquitoes are killed by the end of this period.

Spartan Mosquito Eradicator efficacy graph

If the claims are false or misleading, which seems to be the case, states can classify the device as “misbranded” and issue stop-sell orders. Some have already done so.

These findings will also be important for the class-action suit that has been filed against the company and its owners. I.e., because there is now peer-reviewed evidence that the device does not kill mosquitoes, it will be considerably easier to prove to a jury that the company’s efficacy claims are false or misleading.

Finally, the results call into question the efficacy claims of the company’s newest product, the Spartan Mosquito Pro Tech, which replaces sodium chloride with boric acid. Although a boric acid solution can certainly be lethal if mosquitoes ingest it, the Pro Tech is based on the same design as the Eradicator and thus would not be expected to either attract mosquitoes or to allow them easy access to the fluid inside. The Pro Tech label, however, asserts that the device will attract and kill mosquitoes. It would be great to get a third-party assessment of whether those label claims are true.

Testing the Eradicator and Pro Tech at home

In regards to the question of attractiveness to mosquitoes, consumers can easily assess that at home with a zoom-equipped camera, binoculars, or a security camera. The idea is to be able to see mosquitoes near the cap (if they are there) but to be far enough away so as not to distract the mosquitoes. Ideally, capture a photograph or movie and get confirmation of what insects are actually gathering around the device (again, if any).

Per the above paper, you likely won’t see mosquitoes gathering around the devices. Per the company, mosquitoes will gather around the devices.

People can also assess whether mosquitoes are entering the devices by dumping the contents onto a white plate and taking a photograph. Ideally, share your photographs on Spartan Mosquito’s Facebook page — they’d love to see them. Or post on them on Twitter and cc me (@colinpurrington).

Oak leaf-rolling weevil (Homoeolabus analis)

If you’ve been to Florida and stared at any of the live oaks there, you’ve probably noticed the tiny, burrito-shaped structures on many of these leaves. If you haven’t seen them, you might have heard them — they accumulate under oak trees in sufficient numbers that you’ll hear crunching as you walk over them.

These structures are made by the oak leaf-rolling weevils in the subfamily Attelabinae (the “leaf rolling weevils”, appropriately) and they are called nidi (Latin for “nest” or “place where egg is placed”). Several species ninidify (yes, it’s a verb) oak but perhaps the most common species is Homoeolabus analis. I caught a female in the act:

Zolfo Springs, FL.

This shows her fairly well along in the process but I really wish I could show you a video of her technique, which is amazing. Before this stage she’ll first survey the leaf compulsively, scissor the leaf in half at the midrib, then use mandibles and legs to feverishly roll it into a burrito. Midway through the nidification she’ll deposit an egg (sometimes two) and then, I gather, will guard the nidus from parasitic wasps while it hardens up a bit. She’s also guarding against intrusion by the the thief weevil (Pterocolus ovatus), a blueberry-like attelabid that sneaks into fresh nidi and eats the eggs. But that’s not all. Female thief weevils will leave their own egg inside the nidus and this theft of home is the source of their common name.

Here’s a male, by the way (you can tell because he has a longer neck):

On that note, here’s an egg I found inside one of the nidi. I think it’s Homoeolabus analis but it could be Pterocolus ovatus.

I opened up several dozen of these nidi and found all sorts of drama. Several had some sort of orange cecidomyiid larvae (more pics) in the middle layers of the nidi:

And found plenty of eggs that were definitely not weevil eggs but that are not photogenic enough to post. Suffice it to say that there are many parasitic wasps that have been known to attack this species. If I lived in Florida I’d have hundreds of these in vials just so I could watch the emergers. Better than television.

As a side note, if you have a beetle that looks like Homoeolabus analis, it easily could be Synolabus nigripes, a member of the Attelabinae that also has red, punctate elytra and pronotum; black legs with swollen femora; and long rostrum that is largely though variably black. And ranges overlap (see maps here and here). Below are some ways to tell them apart that I collected from a variety of sources. Many involve knowing which sex an individual is, but luckily males have longer necks. And if an individual is caught nidifying a leaf, it’s a female.

Homoeolabus analis

  • sides of neck parallel, not wider near pronotum (from Boris Büche)
  • males: distance between pronotum and eyes equal to length of rostrum (example)
  • males: pair of spines/projections on the submentum (p. 175 in The Insects and Arachnids of Canada; p. 707 in American Beetles); need a microscope
  • females: straight tibiae (see 2nd pic near top of this post)
  • on, eating, or nidifying Quercus spp.
  • black parts have a blue tinge (see above pic) (LeConte 1876, page 10); this characteristic seems ignored in all later descriptions … but I think it should be featured

Synolabus nigripes

  • width of neck behind eyes greater than width at tip of neck (from Boris Büche)
  • males: distance between pronotum and eyes less than length of rostrum (to me, they evoke the Spy vs Spy comic book characters from Mad Magazine)
  • males: large spine(s) on front femora (example)
  • females: “ventral rostral apex in lateral view with median conical prominence” (American Beetles, p. 707); need a microscope
  • on, eating, or nidifying Rhus spp.; usually sumac, sometimes poison ivy
  • no bluish tinge on black parts (Evans p. 464)

If you still need help IDing, submit a photograph to either iNaturalist (I’m @colinpurrington if you want to tag me in your observation) or BugGuide. Here are Homoeolabus analis observations on iNaturalist.

If you want more information on Homoeolabus analis or the parasites that attack it, here’s a great overview by Donald W. Hall and Lyle J. Buss (both at the University of Florida). And here’s a post by Charley Eiseman with pics and natural history of yet another (but not all-red) oak leaf-rolling weevil, Attelabus bipustulatus. If you want to see some nidifying, there are YouTube videos of various Attelabidae.

Exobasidium ferrugineae

I found this fleshy, flower-like structure growing on Lyonia ferruginea (rusty staggerbush) at Archbold Biological Station (Venus, Florida). Heaths don’t make flowers like this, so I originally thought it might be an insect gall or phytoplasma infection, but I was wrong. After poking around online I think it’s Exobasidium ferrugineae, a Basidiomycetes fungus. Members of the genus grow in between cells of flower and leaf tissue, then in the Spring send hymenial tissue through stomata and other cracks in the epidermis, eventually turning the surface white with spores. I’d never heard of such fungi before. I’ve led a sheltered life.

Exobasidium ferruginea on Lyonia ferruginea (rusty staggerbush). Archbold Biological Station, Venus, FL, USA.

The above was the largest structure I found (perhaps 3 inches high) but there were dozens of others (see below) at the same location. If you’d like to know more about the species and genus, a good starting point is Kennedy et al. 2012 and references therein. In older literature the fungus was known as Exobasidium vaccinii (Burt 1915), but it seems likely that that species is host specific to Vaccinium vitis-idaea.