• Question: A Dragonfly preys on such pesky insects as mosquitoes. How many insects will one dragonfly eat per day?

    Asked by justinaz to Aggelos, Andrew, Eileen, Naomi, Shane on 16 Nov 2012.
    • Photo: Naomi Elster

      Naomi Elster answered on 16 Nov 2012:

      It depends on how many it can catch! Most animals in the wild don’t have the luxury of being able to have a regular diet – they eat whenever they can in order to conserve energy for when food is scarce. However, a dragonfly can eat its own body weight in just 30 minutes!! It is a very fast moving insect and a keen hunter, which means its energy requirements are probably very large too.

      Dragonflies are actually very useful, because they do keep mosquito populations under control, which helps halt the spread of the devastating disease malaria.

    • Photo: Andrew Jackson

      Andrew Jackson answered on 16 Nov 2012:

      good qeustion, and especially in light of mosquitoes carrying diseases like malaria.. if we could use dragonfly to keep their number down that would be a great natural way to prevent disesase.

      Adult dragonfly each mosquitoes by hunting them in the air. But, baby larval mosquitoes are vicious predators that live underwater where larval mosquitoes also live (https://www.google.ie/search?q=dragonfly+larva&aq=f&sugexp=chrome,mod%3D5&um=1&ie=UTF-8&hl=en&tbm=isch&source=og&sa=N&tab=wi&ei=00ymUIPtIsaHhQez74DoDA&biw=1280&bih=963&sei=2EymUNuJCs27hAes34CwCA).

      I found one paper that showed that larval dragonflies would eat up to 14 mosquito larvae in 6 hours. If we let these larval dragonfly feed for 12 hours per day thats approximately 28 mosquito larvae per day.

      I found another science paper that records dragonflies weighing about 500mg had about 30mg of food in their guts. A typical adult mosquito weighs about 2.5mg, so that would imply the dragonflies eat about 12 adult flying mosquitos to fill their guts. After that we would need to know how many times a day a mosquito poops. I have looked, and i cant find anyone that has done any reaserach on pooping dragonflies (at least not the adults… some have studied the larvae). I would guess between 2 and 3 times per day so would roughly estimate that adult dragonflies take between 24 and 36 adult mosquitoes per day.

      Although… larger dragonfly would eat and poop more than smaller ones.

    • Photo: Eileen Diskin

      Eileen Diskin answered on 18 Nov 2012:

      That’s a great question! Andrew did a great job reading through some scientific papers to give you some numbers for how much they’d eat.

      I like dragonflies, they can be really pretty…and also, I don’t like mosquitos, so I’m happy that something wants to eat them!! 😉

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