Comment by akie | Hacker News Reader

Comment by akie | Hacker News Reader

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My wife did her PhD on mosquitos and malaria.

She's been ranting about genetically modified mosquitos for as long as I know her, claiming it cannot and never will work, mainly because mosquitos have an insane amount of offspring and a very short lifespan.

They adapt so, so, so quickly.

A male mosquito lives a week, a female mosquito a few months at best, and they produce 300-600 eggs per female mosquito on average. Can you imagine the exponential growth and recovery rates of these animals? It's like sharing your grandmother with 45000 cousins, and each of your grandmother's 299 siblings has 45000 grandchildren as well. It's a big family very quickly.

There are stories of countries who tried to eradicate mosquitos and reduced the mosquito population to 1% of what it originally was, only to jump back to 100% within two years (or so, my memory is hazy) after the program stopped because politicians had declared the program a success.

Mosquitos man. I'm not sure we'll ever get rid of them. They will probably outlive us.

So they had two full years with a 99% reduction in mosquitos? Shit, even if it doesn’t last, sign me up for that!

In ecology context is everything

Some years are different than other. Last five years were particularly hot and 2020 was the hottest year registered.

Not to mention the wildfires, or the speeding deliberate destruction of the rainforest in the last four years.

Removing trees will remove the rainclouds created by those same trees, and removing the rain means that the place will dry and eventually become arid. Not surprises here.

In both cases we can expect some effect on an animal that breeds on temporary rain pools and lagoons.

Thus, the alleged effect of modified mosquitoes can be zero, or much lower than we think. This effect will be temporary, because mosquitoes are facing similar problems and dry spells for millions of years and they still somehow survived.

That would be weird to go from 1% for 2 years to 100% in an instant. Instead, I will say confidently that it was 1% for an instant, growing to 100% over two years.

I’d still take it!

I wonder what the eradication program entailed.

I don't remember which country it was. I think it was an African country, but I'm not sure. I did find an article [1] about the (failed) eradication of the Aedes aegypti mosquito in Brazil, that contains the following quote:

> In 1973, the Pan American Health Organization again declared that Brazil was Aedes-free. The second official eradication period did not last long. In 1976 and 1977, A. aegypti was found in Rio de Janeiro and Salvador, Bahia, and then in nearly all the Brazilian states.

So, at least three years in their case. Seems you need to eradicate the mosquito from all the neighboring countries as well, otherwise they'll just fly in and fill the void. If you're interested in what they did to declare Brazil Aedes-free (twice), the full article is worth a read:

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5343710/

I once mentioned the obvious flaw in the GMO mosquito plan to my Genetics professor, but he just waved his hand and said "Oh, these folks are smart - they'll figure it out."

It's good to know that my intuition was correct and the field is basically over-promising to local authorities so they can effectively conduct funded genetic experiments in the wild...

Oh, wait a minute... No I'm not... That's a f*ing disaster waiting to happen.

How is the Earth not entirely made out of Mosquitoes then? What are the things that currently limit their growth, maybe it would be good to find out and use those?

Also I’ve been reading up on how Gene Drives work, it’s very interesting but I’ll just leave the Wikipedia page here: https://en.m.wikipedia.org/wiki/Gene_drive

Female mosquitos need blood meals to produce eggs, and a place to lay those eggs which is safe from predation. Both steps can be somewhat controlled by preventing bites onto humans, and by removing standing water, but you will never prevent mosquitos from biting wild mammals or pets, nor will you ever get all of the standing water sources (one old tire could spawn thousands of mosquitos).

One of the biggest limits is weather and climate. Mosquitos don't exist here in New England for half the year, but if we increase the temperature by 2 C, we'll probably be facing them for 7-8 months and they'll rebound harder and faster.

Food. Mosquitoes need blood to reproduce (among other things) and there's a finite supply of that. This caps the population. A very rapid reproduction rate means that they can quickly go from any population size to the max capacity of the environment they are in.

A lot of things eat mosquitoes. A lot. Fish, other insects, birds, bats, other mammals. They eat ridiculous amounts of mosquitoes. A single bat alone can eat its bodyweight in mosquitoes every day.

> How is the Earth not entirely made out of Mosquitoes then?

Mosquitoes are a key species, that feed in turn thousands of other animals: fishes, spiders, predatory flies, bugs, bats, frogs, birds, shrews... etc and suffer heavy loses by that. And they are also pollinators. Mosquitoes are connected with everything and will support everything.

So messing with them is notoriously dangerous. Playing football with a nuclear bomb would be safer probably.

> What are the things that currently limit their growth, maybe it would be good to find out and use those?

Loss of habitat, for example.

> What are the things that currently limit their growth, maybe it would be good to find out and use those?

Now I'm getting worried that some ancient space-ring turns up

https://en.m.wikipedia.org/wiki/Halo_Array

If the mosquito population went to 1% for a couple of years, that seems like a remarkable success.

Upside, that means a gene drive would ruin them extremely fast.

If I understood parent comment, it's that any unmodified mosquitos would quickly fill in any gaps from modified mosquitos who died.

What we need is a gene bomb. Create a gene that makes mosquitos more resistant to gene attacks, but 10 generations later creates infertility. Spend 10 generations dropping gene attacks to ensure those bomb'd mosquitos proliferate and reproduce.

Still, you'll never get all of them.

Gene drives are a way to spread a modification to all of a population because the genetic change has more than a 50% chance of making it into a gamete, all the way up to 100%, so it multiplies up over generations.

And yes it can be combined with a generational ticking time-bomb.

Ok, honest question: What if there's two populations that don't mix? A Gene drive doesn't just teleport, right?

If they literally never mix, it doesn't reach the population it isn't in.

But that's a bigger ask than you'd think. Stuff moves around, on its own, and often, on humans and human artefacts. Like for example, mosquitoes breeding in a puddle on a boat.

This is basically a worry people have about gene drives, that they will jump from places where they are wanted, to wild populations that are doing nobody any harm, and eradicate whole species.

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