Off the Kuff Rotating Header Image

dragonflies

Mutant mosquito update

Keeping you informed on the news you can really use.

Four years ago, the Zika virus became an issue. More than 300 people were infected in Texas. Zika can cause birth defects and fetal neurodevelopmental abnormalities in pregnant women.

The vector is Aedes (rhymes with ladies) aegypti and Aedes albopictus mosquitoes. The Aedes mosquitoes transmit Zika, chikungunya, dengue and yellow fever, which prompted state and county health officials to discuss actionable solutions to control the mosquito.

Talks about releasing genetically modified mosquitoes in Houston began in 2018 between Harris County and Oxitec, a United Kingdom-based company that produces sustainable technologies or transgenic methodologies to stem the impact of disease-spreading insects. Talk also began about a similar action in Monroe County, Fla.

However, ecological concerns have been raised about the use of these mosquitoes.

“We had stakeholders there who wanted to use it,” said Kevin Gorman, head of field operations at Oxitec. “We had vector control authorities who were keen to try the technology.”

The Environmental Protection Agency stated in a May 2020 press release that it approved an experimental use permit to Oxitec to field-test its genetically engineered mosquito in the United States.

The genetically modified Aedes aegypti mosquitoes are males that mate with wild female Aedes aegypti, essentially causing the offspring to die before they can reproduce due to a genetic variation.

Oxitec had two successful years of controlling the Aedes aegypti in Brazil with its current generation of mosquito and had several years of efficacy in Brazil with its first-generation, Gorman said.

[…]

A release in Florida seems imminent, but not in Texas. Despite an established relationship and much communication, it looks like the Florida Keys will be going solo.

“Although we really enjoyed a sort of really great relationship with Houston at the moment we’re in a holding pattern with Houston,” Gorman said. “And we’re unlikely to be releasing there, and there certainly aren’t firm plans to do so in the next year.”

He cited uncertainty due to personnel changes in the county government as the reason for the decision.

A statement sent to Reform Austin by Sam Bissett, a communications specialist with Harris County Public Health, said the choice to not move forward with the release was made last year by both parties.

“At this time, there are no agreements or approval in place for Harris County to work with Oxitec in 2021. While we have had discussions with Oxitec previously about a potential partnership with Harris County Public Health, those discussions were paused last year between both sides.”

See here for my previous post on Oxitec and mutant mosquitoes, from 2017. There’s a lot more to the story and it’s hard to just capture the essence of it, so go read the whole thing. Apparently, the Aedes aegypti mosquito is more abundant in the Rio Grnade Valley than in Harris County, so maybe we’re not the best place to test this out in the US. Harris County also employs mosquito traps and dragonfly armies to control the local skeeter population. Which all seems a whole lot more quaint these days, but Zike and its ilk haven’t gone away just because we’re mostly inside these days. We will be spending more time outside again, and when we do we’d like to not be at significant risk from some other emergent deadly disease, thank you very much. Maybe next time we’ll be able to work something out.

Good luck avoiding mosquitoes

You can’t stop them, you can only hope to contain them.

Living in an area with so many mosquitoes means local officials can’t just ignore them, right? Harris County tries to lower the number of bugs both by spraying and introducing natural predators. The county can’t eradicate them entirely, but it can try to control bugs that have tested positive for diseases like the West Nile virus.

In Harris County, the mosquito problem peaks during the late summer months.

“It spikes up August and September, when it’s high time for hurricane weather that may trigger mosquito breeding to occur,” said Eddie Miranda, a Harris County Public Health spokesman.

Public health trucks rumble through the streets, spraying low-dose pesticides like pyrethrin and malathion to poison mosquitoes. It doesn’t hurt humans to the same degree, although people sensitive to pesticides should go indoors when crews come around. Crews spray one or twice a week in some parts of Midtown, downtown and the Northside.

The county has an app (iOSAndroid) that lets residents enter a ZIP code and find out where spraying is planned. It also includes a digital form to request mosquito breeding site inspection.

There are also other new, natural strategies from county teams to eliminate the pests, such as introducing carnivorous plants and predator bugs to chew them up. Which is good, considering a recent study found a species of mosquitoes found in the South are laying eggs that are better able to survive winter months.

[…]

The New York Times’s Wirecutter has good options for mosquito repellants that aren’t meant to be applied to flesh. Top among their recommendations are Thermacell products, which release a scent-free vapor into the air and rids the immediate vicinity of mosquitoes.

You can spray and kill clouds of mosquitoes in your yard with pyrethrins spray, which targets the nervous system, but it won’t do much for repelling bugs. Citronella candles are also bunk — researchers have disproven the myth that the smell turns mosquitoes off.

Eliminate any still water that’s been outside your home for more than two days. Harris County Public Health recommends replacing the water in your pet’s bowls and birdbaths frequently to avoid mosquito larvae. Check flower pots, open barrels and toys as well.

Bugs need a cozy hiding place such as leaves clogging storm drains. The county recommends sweeping up the first signs of autumn to keep larvae from having a place to feed.

The story has more info about staying skeeter-free – wear long sleeves and long pants, always a delightful prospect in the Houston summer, and slather yourself with DEET – but do mind thosen prevention steps. The big guns around here include high tech traps, dragonflies and damselflies, and mutant mosquitoes. We’re playing the long game, y’all.

New fronts in the war on mosquitoes

Science marches on.

In the center of Anita Schiller’s dragonfly-ring-clad hand, a dragonfly nymph is scooting around.

The dedicated naturalist and entomologist is explaining how the insect (which is a water-dwelling dragonfly with gills before it grows wings) expels water from its posterior in a squirting fashion. She laughed and called it “fart propulsion.”

Schiller is leading a team of four from the Harris County Precinct 4’s Biological Control Initiative through a man-made flood control site at the corner of Spring Cypress Road and Telge Road. They are releasing dragonfly and damselfly nymphs into the water, along with carnivorous plants, to help reduce the infectious mosquito population.

“What we’re bringing in will help stack the deck against mosquitoes,” Schiller, director of the initiative, says. “Mosquito suppression is built into the design of the project.”

The Biological Control Initiative started in 2012 with a mission to “find native agents to benefit from the locally adapted phenotype” to counter the mosquito population.

So, what exactly does that mean?

The agency rears human-friendly biological agents, such as dragonflies, damselflies and carnivorous plants, in a lab to be released into the wild to control the blood-sucking and potentially diseased mosquitoes that afflict Southeast Texas year round.

Dragonflies are robust, while damselflies are more dainty-looking. But both are ferocious eaters as adults and gleaning eaters as nymphs.

Introducing native and naturally flood-resistant plants into wetlands and areas of unavoidable standing water gives a larger return-on-investment than just a pesticide approach, Schiller says. The plants also don’t require regular maintenance.

The initiative has also garnered attention for its introduction of “mosquito assassins” in the Houston area. These mosquitoes, which are typically larger than other native species, do not feed off humans and instead work to eliminate the dangerous mosquitoes, such as Asian tiger (Aedes albopictus), southern house (Culex quinquefasciatus) and yellow fever (Aedes aegypti) mosquito larvae.

As the story notes, Harris County is also using mosquito traps and mutant mosquitoes to control our skeeter population. It’s a big deal, because mosquitoes mean Zika, and standing water means mosquitoes. Do your part to combat the buzzing menace by emptying out whatever pots or containers you have in your yard that fill up with rainwater after a storm. The BCI will take it from there.