Handbook of Nature-Study · Lesson LXXXVII · Topic 13: Aphids and the insects that hunt them
87. Aphids, or plant-lice
Goal: Your child can describe aphids and how they feed, explain what honey-dew is, and name some of their enemies.
You'll need
- A plant with aphids (rose buds, milkweed, nasturtium, garden vegetables)
- A jar of water to stand the stem in
- 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 aphids, "the most helpless and amiable little ninnies in the whole insect world": their beaks thrust into plants, their colors, cast skins, winged and wingless forms, honey-dew, and the ants that tend them. Then Lesson LXXXVII's leading thought, method and eight questions, and an old naturalist's account of an ant milking aphids.
The lesson, step by step
When and where
Late spring to fall, on the tips of rose shoots, milkweed (bright orange aphids), nasturtiums and many garden plants. Comstock's method: "Bring into the schoolroom a plant infested with aphids, place the stem in water and let the pupils examine the insects through the lens."
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:
Aphids have the mouth in the form of a sucking tube which is thrust into the stems and leaves of plants; through it the plant juices are drawn for nourishment. Aphids are the source of honey-dew of which ants are fond.
A colony under the lens
How are the aphids settled on the leaf? Are their heads in the same direction? What are they doing?
Describe an aphid, including its eyes, antennæ, legs and tubes upon the back. Does its color protect it from observation?
Make one move
Nudge one gently with a grass stem.
What does it do in order to leave its place? What does it do with its sucking tube as it walks off? On what part of the plant was it feeding?
Comstock's question 2 ends by asking why Paris green does not kill aphids. Paris green was an arsenic poison sprayed on crops in her day and is no longer used; you can skip that part.
Skins and wings
Can you see cast skins of aphids on the plant? Why does an aphid have to shed its skin?
Are all the aphids on a plant wingless? When a plant becomes dry are there, after several days, more winged aphids? Why do the aphids need wings?
Honey-dew
Do you know what honey-dew is? Have you ever seen it upon the leaf? How is honey-dew made by the aphids?
What insects feed upon this honey-dew?
Look for shiny, sticky leaves under the colony, and for ants walking among the aphids. Then read the leading thought aloud.
Nature notebook
Draw one aphid large, from the side, with its beak in the stem and the two little tubes on its back. Then answer Comstock's question 7 in a list: "What enemies have the aphids?" The next two lessons are about two of them.
Tip
Most of the aphids you see in summer are mothers that give birth to live young without any father, which is why a colony grows so fast.