Smallest Wasp Is Smaller Than An Amoeba

Image 1. A two-inch tarantula hawk wasp dragging an envenomed tarantula across the ground.
Image 1. A two-inch tarantula hawk wasp dragging an envenomed tarantula across the ground. | Source

Big, Small, Tiny

There are more than 600,000 species of wasps in the world. One, called the tarantula hawk (see Image 1), grows to more than two inches long (not counting its legs). It kills tarantula spiders and drags them off to her nest where she then lays a single egg in the carcass.

The species mymar dimidiatus (see Image 2), a member of the wasp family commonly called fairyflies or fairy wasps, averages only one millimeter (mm) in length. There are about 25 millimeters (mm) to the inch. Depending on your browser's font size, the fairy wasp is probably shorter than this dash: -.

Then there is the wasp with the grandiose name megaphragma mymaripenne. It has no common name so, for the purpose of this article (and an ironic twist), it will be referred to as mega. Mega averages five times smaller than dimidiatus at 200 ┬Ám (micrometers), or 1/5 of a millimeter, just twice the width of the average human hair. This wasp is smaller than a single-celled amoeba. Unfortunately, there are no public domain images of mega, so you will have to click on this link to appreciate the astonishing size of this insect, scaled into comparison with an amoeba and a parmecium. When I first saw this image, I was skeptical that such a wasp existed, but it's real all right.

Image 2. A one-millimeter-long Mymar dimidiatus wasp (fairyfly). Still five times larger than megaphragma mymaripenne.
Image 2. A one-millimeter-long Mymar dimidiatus wasp (fairyfly). Still five times larger than megaphragma mymaripenne. | Source

Miracle of miniaturization

So how does a fully functioning insect, with wings, eyes, legs, a brain, muscles, a reproductive system, etc manage to be the size, say, of your average single-celled paramecium? Obviously, mega's thousands of individual cells are much smaller than a paramecium or an amoeba, which happen to be among the largest unicellular organisms in nature, but there is a limit to just how small a cell can be.

Russian scientist Alexey Polilov of Lomonosov Moscow State University thinks he's found the answer to this miracle of miniaturization. He discovered that most of the cells in its central nervous system do not have nuclei. An adult wasp has approximately 7,400 neurons (a housefly has 340,000), which is just enough to allow it to fly, feed, locate hosts and lay eggs. Of those 7,400, only about 350 have nuclei. A cell without a nucleus can be considerably smaller than a comparable cell with a nucleus.

Pupa To Adult To Egg To Pupa

To grow, however, neurons must have a nucleus. The nucleus, among other things, provides necessary proteins for the cell to function. Polilov found that, at the beginning, pupal stage, all of mega's neurons contain nuclei, but when they transition to adults, 95% of the nuclei are destroyed and the neurons take up less space. This loss doesn't seem to affect the functioning of the neurons, so Polilov postulates that proteins are stored when the wasp is a pupa and last long enough to allow the adult to exist up to five days, which is a decent age for such a tiny creature.

Megaphragma mymaripenne wasps seek out thrips in order to lay their own eggs inside the thrips' eggs. Thrips are garden pests that average one mm is size, so thrips eggs are pretty tiny, but of course not so small to mega. When the mega eggs hatch inside the thrips' egg, they feed on their unsuspecting host. Since these microscopic wasps are very particular about their target hosts, researchers are looking into ways to use them to control outbreaks of thrips swarms without harming other insects of use to gardeners and farmers.

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Comments 14 comments

Jackie Lynnley profile image

Jackie Lynnley 4 years ago from The Beautiful South

Those fairy wasps must be what has been after me this summer! I can never see anything but they get me good! I would think it might be fleas or something like that but no one else is getting bit. Now that is a tiny wasp. As far as their life span I would say it is about 4 days too many. Very intelligent write though and I enjoyed it. I like bugs. Well, as long as they don't bite me.


UnnamedHarald profile image

UnnamedHarald 4 years ago from Cedar Rapids, Iowa Author

I daresay you wouldn't see them coming, Jackie. Thanks for reading and commenting. Personally, I find it all a bit unsettling, these basically invisible wasps in addition to all the other invisible things crawling and floating around. Fascinating though.


Mhatter99 profile image

Mhatter99 4 years ago from San Francisco

Fascinating, to say the least. Thank you.


Larry Fields profile image

Larry Fields 4 years ago from Northern California

Speaking of smallish wasps, I remember reading that there's a tentative answer to the question of declining honeybee populations. Some Luddite environmentalists have even blamed cell phone towers! Apparently, the bees are parasitized by tiny wasps. Anyway, that's the latest buzz from the scientific world.

Voted up and interesting.


UnnamedHarald profile image

UnnamedHarald 4 years ago from Cedar Rapids, Iowa Author

Thanks for the thumbs up, Mhatter99. Glad you liked it.


UnnamedHarald profile image

UnnamedHarald 4 years ago from Cedar Rapids, Iowa Author

Larry, yes, I'd heard about the "tiny wasp" theory, too, but I certainly never appreciated how tiny a tiny wasp could be until I came across this tiny fellow. Thanks for the vote up.


jessefutch profile image

jessefutch 4 years ago from North Carolina

This was a truly intelligent and interesting read. Fantastic hub, creepy wasps.


UnnamedHarald profile image

UnnamedHarald 4 years ago from Cedar Rapids, Iowa Author

Thanks for the comment and compliment, jessefutch. It is pretty creepy that there are wasps so small you can't really see them. Creepy, crawling flying wasps as small as amoebas. Yep.


DDE profile image

DDE 4 years ago from Dubrovnik, Croatia

One of the most educational topics on HP


UnnamedHarald profile image

UnnamedHarald 4 years ago from Cedar Rapids, Iowa Author

DDE, I am flattered and encouraged by your comment. I'm glad you enjoyed it as much as I did researching and writing it.


carol7777 profile image

carol7777 4 years ago from Arizona

Who knew all this about these little creepy crawling little beings. However, I am always glad to learn more new things. Very good and informative hub.


UnnamedHarald profile image

UnnamedHarald 4 years ago from Cedar Rapids, Iowa Author

Hi carol. Hope the new knowledge doesn't keep you up at night :) Thanks for your comment.


joedolphin88 profile image

joedolphin88 2 years ago from north miami FL

Wow never knew a wasp could be that small, I wonder what it would be like to be bitten by one that small. Very educational hub.


UnnamedHarald profile image

UnnamedHarald 2 years ago from Cedar Rapids, Iowa Author

I couldn't believe it either when I first heard about it (you mean everything on the Internet isn't true?). I did further digging and it's all true. Thanks for reading and commenting, joe.

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