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Who needs mosquitoes?
Nature of 22 july 2010 features an article called a world without mosquitoes. The author seems to think that mosquitoes are only a nuisance ( causing malaria, yellow fever etc) and that eradication would not have serious consequences for the ecosystem. One argument posed is that most mosquitoe eating birds would switch to other insects. Another line of reasoning goes as follows: thousands of plant species depend on mosquitoes for pollination. But pollination isn't crucial for crops on which humans depend. The only thing we want from mosquitoes is for them to go away. And according to entomologist Joe Conlon they (mosquitoes) don't occupy an unassailable niche in the environment. My question: how do malaria researchers feel about programmes aimed at eradication of mosquitoes??
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Usa
This was an interesting article that deserves attention now that malaria elimination is firmly back on the agenda.
This question is often posed by journalists: 'So what if we eliminate all mosquitoes?'. My answer always has six points:
1) Mosquito elimination has only been successful in very few places. Malaria elimination is what we are after.
2) In places where intense mosquito control in the past led to the elimination of malaria, we have no records of disrupted ecosystems or drastic changes in biodiversity as a result of that.
3) Mosquitoes play a dominent role in their aquatic stages in providing food to a host of other organisms (e.g. fish). However, most of the really important anophelines breed in temporary sunlit pools that have very little in terms of biodiversity. Take a hoof print filled with rain water. Practically the only organisms you will find in it are mosquito larvae. Removing these will not have a major impact.
4) Mosquitoes occupy a low place in the food chain, alongside numerous other invertebrates that can serve as food for higher organisms that predate on them. Removing mosquitoes would lead to a shift in prey range, and would only have consequences if predators were highly specialised on mosquitoes. To my knowledge there are no higher organisms that depend solely on mosquitoes for their survival.
5) A study in Germany revealed that bats do not depend heavily on adult mosquitoes for their survival. Again, there stomachs were filled with many different insects.
6) As for pollination, I would like to see data of the contribution of mosquitoes. I have not come across any info, but may have missed something.
All in all I am of the opinion that the complete removal of mosquitoes, particularly in areas where they transmit potentially lethal diseases, is warranted.
I hate mosquitoes and would like to see them gone.
However there are other things to consider:
1) Some species may have there numbers controlled by mosquitoes, such as the Moose (I believe) in North America. Eradication of mosquitoes may change the ecology at least temporarily.
2) Malaria is not the only disease carried by mosquitoes, e.g. Dengue Fever.
Location
At first i read the question, i thought that might have somebody need to donate the mosquitoes:(( for my laboratory on salivary protein research. However I understand now,
1. I think the mosquitoes could not be eradicated, eventhough we could eliminate but for my research on the biology characteristics of malaria and filariasis vectors, in the south of Thailand post-tsunami affected areas compared to the past many years, we found that there have a bit high pH , DO, Temp, etc at the breeding sites, the mosquito larval densities are higher around over 100-150 mosquito larva/dips, and some Anopheles could breed on brackish-water and polluted with garbage.
2. the very important measure should be focus on human behavioral change plus LLIBN. During my action research last 2 years, i observed the bednet uses of the population in many communities at night times, i found many family has only 1 net or none (very poor) with too many people in there, and many houses , they left the net under the floor sheet etc in pack (dont use), Other problems we have met were the biting time change (Anopheles can bite since 5-6 pm till 7 am). They could bite all the time not ever night time for Anopheles and day time for Aedes for example, the preferable time has changed, these problems should be reconsidered.
3. The other thing, is the mesh of bednet according to the smaller size of adult mosquito, which due to the duration of development (growth cycle is shorter) esp; L1-L2, L2-L3, L3-L4, pupa and adult are 1-2-3 days, shorter than the past, (unpublish data), affect to the entrance of nets mesh.
4. the adult mosquito resistance to the insecticides should be concerned. And should be more study on natural products to protect mosquito biting and insecticide control measures.
5. the Toxorynchites larva and micronecta spp were used to eliminate Aedes mosquito larva, we found the different stages larva can be eradicated (unpublish) with the different concentration of insecticide (we defense the 1 ppm WHO temephos recommend ).
Cheers all
Usa
Usa Lek-Uthai,
Mahidol University,
Bangkok, Thailand