# Mosquitos: "the eco-system doesn't need them" **URL:** \ **Category:** In My Humble Opinion\ **Created:** [February 1, 2016, 9:35pm UTC](https://boards.straightdope.com/t/mosquitos-the-eco-system-doesnt-need-them/744882 "2016-02-01T21:35:56Z")\ **Posts on this page:** 10\ **Page:** 4
**Author:** ![WordMan](https://avatars.discourse-cdn.com/v4/letter/w/e8c25b/32.png) [@WordMan](https://boards.straightdope.com/u/WordMan)\ **Post date:** [February 5, 2016, 6:20pm UTC](https://boards.straightdope.com/t/mosquitos-the-eco-system-doesnt-need-them/744882/61 "2016-02-05T18:20:51Z")
> [@snowthx](#): > > I want to thank you, **mozchron** , for your excellent and informative posts on the zika outbreak and mosquitoes. Your posts on the board here have been authoritative, easy for this non-scientist to understand, and the kind of information that makes this place so great. > > I nominate you for this month’s unofficial SDMB Ignorance Fighting Warrior award! 🙂 Yes, indeed! I ask a simple question and get a great, complex but understandable answer. BBC Newshour on NPR just inteviewed a Brit about this, again. The whole concept of “local suppression” was discussed. One point this person made: Look at the scientific name of the mosquito in question: “aegypti” - these insects are from Egypt. He cited a Brazilian report from 50 years ago related to tracking Dengue fever where it was noted that A.Aegypti was NOT PRESENT in Brazil at the time, so they weren’t dealing with that disease. So by eradicating A.A., they would be returning Brazil closer to how it was 50 years ago, with more indiginous skeeters more abundant. Humans’ globalization has so many ramifications…and a completely different way to look at the question in the OP. ---
**Author:** ![foolsguinea](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/foolsguinea/32/14751_2.png) [@foolsguinea](https://boards.straightdope.com/u/foolsguinea)\ **Post date:** [February 5, 2016, 10:33pm UTC](https://boards.straightdope.com/t/mosquitos-the-eco-system-doesnt-need-them/744882/62 "2016-02-05T22:33:56Z")
> [@mozchron](#): > > I don’t know. Is it you/you family at risk or anonymous brown people “over there”? > > Its a serious question. IME the people who rail against tech like GM mosquitoes (or DDT etc…) tend to live in comfortable, rich western countries. Arguments against using them often devolve into “there are too many people in the world anyway” - again, its OK when its poor anonymous brown people doing the dying. > > People in affected areas usually are big supporters of the technology. If there is a huge Zika-induced microcephaly outbreak in the States I fully expect massive calls to deploy anything and everything that might help, ecology be damned. > > On edit, I don’t mean to sidetrack the thread but this is an issue that really grates me. No, I mean, ultimately we can vaccinate for this as for rubella, but I just don’t want to do more ecological damage just because the risk of this manages to find synergy with anti-insect bias. ---
**Author:** ![mozchron](https://avatars.discourse-cdn.com/v4/letter/m/c2a13f/32.png) [@mozchron](https://boards.straightdope.com/u/mozchron)\ **Post date:** [February 6, 2016, 2:38pm UTC](https://boards.straightdope.com/t/mosquitos-the-eco-system-doesnt-need-them/744882/63 "2016-02-06T14:38:17Z")
> [@foolsguinea](#): > > No, I mean, ultimately we can vaccinate for this as for rubella, but I just don’t want to do more ecological damage just because the risk of this manages to find synergy with anti-insect bias. A vaccine won’t be available for at least 3-5 years (if at all). What do we do in the meantime? What ecological damage are you referring to? GM sterile mosquitoes basically don’t alter the ecology at all except for suppressing population levels of Aedes aegypti, which isn’t native to the area at any rate. The alternative (which is being done) is to spray insecticides. I guarantee you this has a MUCH greater effect on the ecological system (non-target effects and vertebrate toxicity). Pretend you’re the one making policy. Millions of people are getting sick and babies are born with brain damage NOW. What are you going to do about it? ---
**Author:** ![HeXen](https://avatars.discourse-cdn.com/v4/letter/h/c89c15/32.png) [@HeXen](https://boards.straightdope.com/u/HeXen)\ **Post date:** [February 6, 2016, 2:48pm UTC](https://boards.straightdope.com/t/mosquitos-the-eco-system-doesnt-need-them/744882/64 "2016-02-06T14:48:45Z")
Why even discuss an idea that’s impossible anyway? You cannot rid the entire world of mosquito’s any more than we could cockroaches…at least not without destroying half the planet in the process. ---
**Author:** ![mozchron](https://avatars.discourse-cdn.com/v4/letter/m/c2a13f/32.png) [@mozchron](https://boards.straightdope.com/u/mozchron)\ **Post date:** [February 6, 2016, 2:58pm UTC](https://boards.straightdope.com/t/mosquitos-the-eco-system-doesnt-need-them/744882/65 "2016-02-06T14:58:54Z")
> [@HeXen](#): > > Why even discuss an idea that’s impossible anyway? You cannot rid the entire world of mosquito’s any more than we could cockroaches…at least not without destroying half the planet in the process. You’re laboring under a big misunderstanding. Goal isn’t to eliminate all mosquitoes worldwide. That is, as you say, impossible (also stupid). We’re talking about suppressing or eliminating specific species in a defined local area. There are about 3500 species of mosquitoes. Not all of them transmit pathogens, and of those that do, an even smaller fraction transmit pathogens to people and domestic animals (which are really the ones we care about). Maybe 200 (I don’t know the exact number). Of these there are probably about 50 species that are really important, and maybe 10 that are REALLY important (scientists may quibble about the specific numbers but i’m in the right order of magnitude). Aedes aegypti, the mosquito we’re talking about here, is one of the REALLY important species. It is not native to the western hemisphere. It was almost eliminated from the americas once (by drenching the whole place insecticide). We can do it again. ---
**Author:** ![CarnalK](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnalk/32/486_2.png) [@CarnalK](https://boards.straightdope.com/u/CarnalK)\ **Post date:** [February 6, 2016, 3:05pm UTC](https://boards.straightdope.com/t/mosquitos-the-eco-system-doesnt-need-them/744882/66 "2016-02-06T15:05:27Z")
> [@foolsguinea](#): > > No, I mean, ultimately we can vaccinate for this as for rubella, Dengue fever doesn’t have an effective vaccine yet. Why so confident? ---
**Author:** ![Deeg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/deeg/32/2955_2.png) [@Deeg](https://boards.straightdope.com/u/Deeg)\ **Post date:** [February 6, 2016, 11:10pm UTC](https://boards.straightdope.com/t/mosquitos-the-eco-system-doesnt-need-them/744882/67 "2016-02-06T23:10:25Z")
> [@mozchron](#): > > What ecological damage are you referring to? GM sterile mosquitoes basically don’t alter the ecology at all except for suppressing population levels of Aedes aegypti, which isn’t native to the area at any rate. Haven’t you seen any Hollywood movies?!? Surely someone will cross mosquito genes with Dick Chaney; what a disaster that will be when released into the wild. ---
**Author:** ![foolsguinea](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/foolsguinea/32/14751_2.png) [@foolsguinea](https://boards.straightdope.com/u/foolsguinea)\ **Post date:** [February 7, 2016, 5:51am UTC](https://boards.straightdope.com/t/mosquitos-the-eco-system-doesnt-need-them/744882/68 "2016-02-07T05:51:12Z")
OK, you’ve sold me on trying to get rid of\* A. aegypti\* in the Americas. ---
**Author:** ![Sasquatch\_1](https://avatars.discourse-cdn.com/v4/letter/s/8491ac/32.png) [@Sasquatch\_1](https://boards.straightdope.com/u/Sasquatch_1)\ **Post date:** [February 7, 2016, 3:27pm UTC](https://boards.straightdope.com/t/mosquitos-the-eco-system-doesnt-need-them/744882/69 "2016-02-07T15:27:56Z")
Interesting info below - how about instead of turning on the gene permanently, wouldn’t it be better to adjust the mosquito genetics so the hormone is fully-on after 1 blood meal (of any size, so it is full off to full on). Mosquito biting isn’t really the problem for being disease vectors, its biting more than once… Allowing one blood meal seems less of an evolutionary strike that totally removing it. Most would probably still have decent fertility from just one meal so it wouldn’t affect the natural population as much. > [@mozchron](#): > > What we do isn’t magic you know, its hard! > > That being said, there might be a kernel of wisdom in this. In Aedes aegypti (and ONLY in Aedes aegypti - this doesn’t apply to other mosquito species) there is a gene called “Aedes head peptide” which is a protein hormone turned on in the mosquito brain after taking a blood meal. When it is expressed, it turns off host-seeking behavior and the mosquito doesn’t feed anymore. > > Other mosquitoes presumably have similar head peptide genes, but they are so different at the sequence level we have not been able to pull them out of the genomes. Aedes head peptide was isolated old-school in the 1980’s - fractionating mosquito head extracts and injecting them one by one into mosquitoes to see what they did. > > There are also mosquitoes that can lay a batch of eggs without taking a bloodmeal. This is called “autogeny”. In this case, the mosquitoes store up lots of nutrients as larvae and use them for eggs when they are adults. Problem is it only happens once - after laying the first egg batch they need a bloodmeal for the subsequent ones. > > Autogeny is a complex trait involving lots of things we don’t fully understand. Aedes aegypti is not widely autogenous (i.e. they generally need blood for eggs), but the trait has been found at low frequencies in some studies. > > So what we would have to do is engineer Aedes to express head peptide constitutively in their brains to turn off bloodfeeding, while at the same time engineering them to be autogenous. They would lay a single batch of eggs and never feed again. This would have a big fitness cost (as they would have less offspring than wild-type) so we’d have to link the whole thing to a gene drive (probably based on CRISPR/Cas9) to push it into the population. > > Easy-peasy. Give me about 20-40 million dollars and 10 years and I think we could do it! ---
**Author:** ![mozchron](https://avatars.discourse-cdn.com/v4/letter/m/c2a13f/32.png) [@mozchron](https://boards.straightdope.com/u/mozchron)\ **Post date:** [February 7, 2016, 8:00pm UTC](https://boards.straightdope.com/t/mosquitos-the-eco-system-doesnt-need-them/744882/70 "2016-02-07T20:00:34Z")
> [@Sasquatch](#): > > Interesting info below - _**how about instead of turning on the gene permanently, wouldn’t it be better to adjust the mosquito genetics so the hormone is fully-on after 1 blood meal (of any size, so it is full off to full on)**_. Mosquito biting isn’t really the problem for being disease vectors, its biting more than once… Allowing one blood meal seems less of an evolutionary strike that totally removing it. Most would probably still have decent fertility from just one meal so it wouldn’t affect the natural population as much. Sure, it would be better. But also much more complicated to do so. I can (relatively) easily see how to turn it on when the adult emerges and and keep it on. Much harder to do what you’re suggesting. But I have no doubt it could be done, it would just take more work. Allowing mosquitoes to live long enough to reproduce but not long enough to transmit pathogens is a core principle behind the idea of “Evolution-Proof” or “Evolution-Resistant” control strategies. Lots of people working on those (myself included). [Previous page](https://boards.straightdope.com/t/mosquitos-the-eco-system-doesnt-need-them/744882.md?page=3)