Answers.Body: <p>Mosquito wing flapping produces a large amount of acoustic power as compared to their size (<a href="https://10.1088/1748-3190/ac0120" rel="nofollow noreferrer">for instance, several times more powerful than a fruit fly, pound-for-pound</a>). <strong>It is very unlikely that any mosquito species recently evolved to be quieter;</strong> I see at least two reasons for this:</p>
  <ol>
  <li><p>The loud sound of mosquito flight is essential for mating to happen, since males use the flight sound of females to detect them. At least, it is well established for more than a century that males move toward the sound of females (<a href="https://www.biodiversitylibrary.org/part/182971" rel="nofollow noreferrer">Knab 1906</a>, <a href="https://doi.org/10.2307/2421604" rel="nofollow noreferrer">Roth 1948</a>, <a href="https://doi.org/10.4269/ajtmh.1949.s1-29.811" rel="nofollow noreferrer">Kahn &amp; Offenhauser 1949</a>).</p>
  </li>
  <li><p>Mosquitoes have evolved along side their blood host for thousands of years (e.g. <a href="https://doi.org/10.1002/9780470514948.ch4" rel="nofollow noreferrer">the divergence in very closely-related species are believed to have happened ~5,000 years ago</a>)), so it means they are already &quot;quiet&quot; enough to efficiently bite without being killed if their species made it till now.</p>
  </li>
  </ol>
  <p><strong>So why do you feel that they have been quieter recently?</strong>  This is more difficult to answer, but I can speculate:</p>
  <ul>
  <li>the quiet mosquitoes  are probably not the same species as the loud ones and the population of the loud species may have dropped for whatever reasons (changes in environmental conditions around the place where you live, especially related to aquatic larva breading, drought, ....)</li>
  <li>mosquitoes have been prevented from reaching your quiet room at night (e.g. better room insulation from outside, use of mosquito repellent, etc); you are still bitten outside but the ambient sound background avoids you hearing them as much as in a quiet bedroom</li>
  </ul>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-08-28T09:20:38.133Z
Answers.Text: I am sleeping fewer hours as I age so I have considered the likelihood that my confirmed hearing loss is a contributing factor but friends and family have also confirmed that these flying insects are less audible. I know of midges, they *sound* soundless, and bite during the day, but they reside in stagnant waters. I don't live anywhere near a canal, pond or somebody's neglected pool!
Answers.UserDisplayName: Mari-Lou A
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-08-28T09:22:23.487Z
Answers.Text: P.S I am scratching my ankle as I type ;(
Answers.UserDisplayName: Mari-Lou A
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Answers.CreationDate: 2022-08-28T09:34:57.590Z
Answers.Text: any changes in ways the raining/waste water drainage is handled? that could affect some species.
Answers.UserDisplayName: Noil
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Answers.CreationDate: 2022-08-28T09:46:53.803Z
Answers.Text: No, no change. In the past, I could definitely hear them buzzing.  And when the anti-mosquito plug-in needs refilling I know because that's when the insects come to bite me.
Answers.UserDisplayName: Mari-Lou A
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Answers.LastEditDate: 2022-08-28T16:09:29.230Z
Answers.UserDisplayName: Noil
Answers.Body: <p>I want to expand in Noil's argument that it's a different species of mosquito. In fact, <a href="https://en.wikipedia.org/wiki/Aedes_albopictus" rel="nofollow noreferrer">tiger mosquito</a> (Aedes albopictus) seems a likely candidate for the cause of your corncerns:</p>
  <ul>
  <li>It has been expanding in Europe in recent decades (<a href="https://it.wikipedia.org/wiki/Aedes_albopictus#Specie_invasiva" rel="nofollow noreferrer">Italy included</a>), and therefore it's likely to be new in a lot of places and for a lot of people.</li>
  <li>It also bites during the day.</li>
  <li>It seems to be less noisy than other species. Wikipedia mentions &quot;<strong>the characteristic whine, almost inaudible to humans, of the female</strong>&quot;.</li>
  <li>Its bite is more annoying that other species.</li>
  <li>It doesn't need large water surfaces (like canals or wetlands) to reproduce. Therefore it can colonise places that used to be mosquito-free.</li>
  </ul>
  <p>The features of the tiger mosquito seem to match your description. Furthermore, my unpleasant experience of finding such mosquitoes in different points in Catalonia also matches yours in Italy.</p>
  
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Answers.CreationDate: 2023-01-15T23:26:06.140Z
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Answers.UserDisplayName: Pere
Body: <p>I live in northern Italy and until three or four years ago  I would easily hear the annoying buzzing sound mosquitoes made at night while I lay under the sheets.</p>
  <p>But that's no longer true. Apart from the fact that these insects are active both day and night, I don't hear them make the same unmistakable noise as before.</p>
  <p>Have mosquitoes in Italy or worldwide, evolved to be more silent so they are able to bite their prey in &quot;stealth&quot; mode?</p>
  <p>I searched Google for <a href="https://youtu.be/Rcm3rPz_Q94?t=93" rel="nofollow noreferrer">why mosquitoes make a buzzing noise</a> and discovered that the noise is derived from the beating of their wings. In addition, the male mosquito pitch is significantly higher than the female but when two mosquitoes of the opposite sex meet, the difference in pitch disappears and they perform a &quot;duet&quot;. So, no mention of mosquitoes being quieter today than in the past. Is it my imagination?</p>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2022-08-28T09:29:26.547Z
Comments.Text: do the quiet ones still come to bite you at night?
Comments.UserDisplayName: Noil
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2022-08-28T09:48:49.143Z
Comments.Text: @Noil Occasionally, but I normally use an anti repellent in the house, they bite when it needs a refill, i.e. today. I mostly get bitten when I am in restaurants, barbecues, and in the evenings at friends' home if they don't have one of those anti-mosquito devices that can be plugged in. One the best  brands is called Vape in Italy, no idea if it has the same name in the US.
Comments.UserDisplayName: Mari-Lou A
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2022-08-31T22:03:02.263Z
Comments.Text: Thank you for this question! I noticed this recently here in California. In San Diego it used to be rare to have mosquitos, but I just received more bites in last hour than I did in my first 5 years here. All were silent and I have only occasionally heard them. Age + career in bioacoustics also affects my hearing, but I am VERY tuned into that evil buzz!!
Comments.UserDisplayName: Shannon
Tags: <insect><evolution><mosquitoes>
Title: Have mosquitoes evolved to be quieter?
ThreadText: # Have mosquitoes evolved to be quieter?
  
  (Asked by: username_0 on 2022-08-27)
  
  I live in northern Italy and until three or four years ago I would easily hear the annoying buzzing sound mosquitoes made at night while I lay under the sheets.
  
  But that's no longer true. Apart from the fact that these insects are active both day and night, I don't hear them make the same unmistakable noise as before.
  
  Have mosquitoes in Italy or worldwide, evolved to be more silent so they are able to bite their prey in "stealth" mode?
  
  I searched Google for [why mosquitoes make a buzzing noise](https://youtu.be/Rcm3rPz_Q94?t=93) and discovered that the noise is derived from the beating of their wings. In addition, the male mosquito pitch is significantly higher than the female but when two mosquitoes of the opposite sex meet, the difference in pitch disappears and they perform a "duet". So, no mention of mosquitoes being quieter today than in the past. Is it my imagination?
  
  **Tags:** insect, evolution, mosquitoes
  
  > **Comments:**
  > **username_1**: do the quiet ones still come to bite you at night?  
  > **username_0**: @username_1 Occasionally, but I normally use an anti repellent in the house, they bite when it needs a refill, i.e. today. I mostly get bitten when I am in restaurants, barbecues, and in the evenings at friends' home if they don't have one of those anti-mosquito devices that can be plugged in. One the best  brands is called Vape in Italy, no idea if it has the same name in the US.  
  > **username_2**: Thank you for this question! I noticed this recently here in California. In San Diego it used to be rare to have mosquitos, but I just received more bites in last hour than I did in my first 5 years here. All were silent and I have only occasionally heard them. Age + career in bioacoustics also affects my hearing, but I am VERY tuned into that evil buzz!!  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_1 on 2022-08-27. Score: 5
  
  Mosquito wing flapping produces a large amount of acoustic power as compared to their size ([for instance, several times more powerful than a fruit fly, pound-for-pound](https://10.1088/1748-3190/ac0120)). **It is very unlikely that any mosquito species recently evolved to be quieter;** I see at least two reasons for this:
  
  1. The loud sound of mosquito flight is essential for mating to happen, since males use the flight sound of females to detect them. At least, it is well established for more than a century that males move toward the sound of females ([Knab 1906](https://www.biodiversitylibrary.org/part/182971), [Roth 1948](https://doi.org/10.2307/2421604), [Kahn & Offenhauser 1949](https://doi.org/10.4269/ajtmh.1949.s1-29.811)).
  2. Mosquitoes have evolved along side their blood host for thousands of years (e.g. [the divergence in very closely-related species are believed to have happened ~5,000 years ago](https://doi.org/10.1002/9780470514948.ch4))), so it means they are already "quiet" enough to efficiently bite without being killed if their species made it till now.
  
  **So why do you feel that they have been quieter recently?** This is more difficult to answer, but I can speculate:
  
  * the quiet mosquitoes are probably not the same species as the loud ones and the population of the loud species may have dropped for whatever reasons (changes in environmental conditions around the place where you live, especially related to aquatic larva breading, drought, ....)
  * mosquitoes have been prevented from reaching your quiet room at night (e.g. better room insulation from outside, use of mosquito repellent, etc); you are still bitten outside but the ambient sound background avoids you hearing them as much as in a quiet bedroom
  
  > **Comments:**
  > **username_0**: I am sleeping fewer hours as I age so I have considered the likelihood that my confirmed hearing loss is a contributing factor but friends and family have also confirmed that these flying insects are less audible. I know of midges, they *sound* soundless, and bite during the day, but they reside in stagnant waters. I don't live anywhere near a canal, pond or somebody's neglected pool!  
  > **username_0**: P.S I am scratching my ankle as I type ;(  
  > **username_1**: any changes in ways the raining/waste water drainage is handled? that could affect some species.  
  > **username_0**: No, no change. In the past, I could definitely hear them buzzing.  And when the anti-mosquito plug-in needs refilling I know because that's when the insects come to bite me.  
  
  ---
  
  ### Answer by username_3 on 2023-01-15. Score: 3
  
  I want to expand in username_1's argument that it's a different species of mosquito. In fact, [tiger mosquito](https://en.wikipedia.org/wiki/Aedes_albopictus) (Aedes albopictus) seems a likely candidate for the cause of your corncerns:
  
  * It has been expanding in Europe in recent decades ([Italy included](https://it.wikipedia.org/wiki/Aedes_albopictus#Specie_invasiva)), and therefore it's likely to be new in a lot of places and for a lot of people.
  * It also bites during the day.
  * It seems to be less noisy than other species. Wikipedia mentions "**the characteristic whine, almost inaudible to humans, of the female**".
  * Its bite is more annoying that other species.
  * It doesn't need large water surfaces (like canals or wetlands) to reproduce. Therefore it can colonise places that used to be mosquito-free.
  
  The features of the tiger mosquito seem to match your description. Furthermore, my unpleasant experience of finding such mosquitoes in different points in Catalonia also matches yours in Italy.
  
  
  ---
  
  