Handbook of Nature-Study · Lesson XC · Topic 14: Mosquitoes, flies and beetles
90. The mosquito
Goal: Your child can find mosquito wrigglers, describe how they breathe at the surface, and explain how emptying standing water stops mosquitoes.
You'll need
- A rain barrel, bucket, flowerpot saucer or birdbath with standing water
- A clear jar with a tight lid of fine cloth held by a rubber band
- A spoon or turkey baster
- A hand lens (magnifying glass)
- A nature notebook and a pencil (colored pencils if you have them)
What's in the book
Comstock's story of the mosquito: the boat-shaped egg rafts floating in rain barrels, the wrigglers that hang from the surface by a breathing tube, the pupae that rest with the other end up, and the harmless and the dangerous kinds of adults. Then Lesson XC with questions on the larva, the pupa and the adult.
The lesson, step by step
When, where and safety
Summer into September. Look in any standing water that has sat for a week: rain barrels, buckets, old tires, saucers under flowerpots, clogged gutters, birdbaths. Comstock suggests looking for the floating egg rafts too.
Safety: keep the wrigglers in a jar with a tight cloth cover, and look at them for a day or two only. Then pour the water onto dry ground or pavement before any of them can turn into biting adults. Mosquitoes can spread illness.
Keep the big idea in mind
Comstock's "leading thought" is the one idea the lesson is meant to lead to. Read it to yourself now, and save it to share at the end, after your child has looked and answered:
The wrigglers, or wigglers, which we find in rain-barrels and stagnant water are the larvæ of mosquitoes. We should study their life history carefully if we would know how to get rid of mosquitoes.
Wrigglers at rest
Scoop a few wrigglers into the jar with plenty of their water and let them settle.
Where do they rest when undisturbed? Do they rest head up or down? Is there any part of their body that comes to the surface of the water?
Observe one resting at the top. At what angle does it hold itself to the surface of the water? Observe its head. Can you see the jaw brushes revolving rapidly? What is the purpose of this?
Wrigglers on the move
Tap the jar gently.
When disturbed what do they do? When they swim, do they go head or tail first? When they float do they go upward or downward?
The breathing tube at the tail end is why they must keep coming back to the top.
The tumbler
Look for wrigglers with a big rounded front end. These are the pupae.
What is the most noticeable difference in appearance between the larva and pupa?
When the pupa rests at the surface of the water, is it the same end up as the wriggler?
Grown-up mosquitoes
Use the book's pictures, or a mosquito resting on a wall.
When at rest, is it shortened and humpbacked or does it stand straight out with perhaps its hind legs in the air?
Which sex of the mosquito does the biting and the singing?
Only the mothers bite: they need a meal of blood to make their eggs. The males, with feathery antennæ, drink plant juices.
Put it into words
Read the leading thought aloud and ask: Now that we know where wrigglers live, how can we get rid of mosquitoes around our house? (Tip out standing water once a week.) Then go and do it, and pour out the jar.
Nature notebook
Draw a wriggler hanging from the surface by its tail tube, a pupa with its two breathing "ears", and an adult mosquito. Draw arrows to show the order.
Tip
What we know now: Comstock teaches children to tell the malaria mosquito (Anopheles) from the common kind. Malaria was wiped out in the United States by the early 1950s, but mosquitoes still spread other illnesses, such as West Nile virus. She also asks why kerosene oil on the water kills wrigglers; people did that then, but today we tip out the water instead, which doesn't harm other pond life.