This is an article I rescued from the “ancient” web archives. I originally wrote this article back in the early 90’s.
Introduction
Science is driven by questions. For students to experience the process of
science they should work on answering questions that arise from their natural
curiosity. Ant lions (Neuroptera) and their intriguing behaviors naturally generate
student questions. Since most students are not familiar with “doodlebugs”, ant lions
make an effective way to open the school year. If a few students have prior
experience with ant lions this only adds to the effectiveness of the activity.
Day 1 Activity
On the first day of class, my students find a four-ounce, low-form cup of sand at
their desks, one for each student. In the middle of the sand is a small conical
depression. From the very beginning of class, students begin to ask questions. The
first questions range from: “What are we supposed to do with this?” to “How did you
make that hole?” I respond by asking them to record some measurements of the pit
and draw a simple sketch.
Several at this point end up collapsing the pit accidentally as they move the
cups around to make observations. If I am patient at this point, the ant lions in the
collapsed pits will begin to repair the damage after a short period of time. Once the
students realize that a living organism is at the bottom of the pit I am inundated
with questions. “What is that?” “Did it make this hole?” “Why” “What does it look
like?”
From this point, we will bring in potential prey items such as ants or flour beetles.
Once they see a pit and the ant lion in action I don’t have to do much the rest of the
day except turn their questions back to them in a manner that is supportive but
develops question and observation skills. I ask that they record their thoughts,
observations, and questions as they investigate their ant lions. When they want to
use microscopes or stereoscopes I get them out so they can. We simply explore. This
opening day activity serves two purposes. One, it jump-starts the students into
inquiry-based science, and two, it helps me to establish appropriate questioning skills
as I help the students develop their general, curiosity-based questions into questions
and hypotheses that are suitable for scientific investigation.
Day 2 Activity
The next day we bring out the ant lions again, feed them, and then begin to explore
the notes and observations made the day before. I select some questions and
observations that seem to be particularly promising and ask questions of the
students to direct them toward a working hypothesis that is suitable for experimental
design. For instance, invariably the students notice that the pits are of different sizes
and ask the question “Why?” If I wait long enough a student will usually speculate
that the size of ant lions might have something to do with the size of the pit. I focus
on this and ask for suggestions on how we might examine this idea. What kind of
predictions can we make? How can we limit the scope of our questions so that we can
satisfactorily answer them? Of course, we are working on hypothesis formation but
they aren’t aware of this just yet. Soon we have developed a method of investigating
this question and started collecting data. We work on this methodology so that
students can start to work on focusing their own, personal questions about ant lions
into working hypotheses.
Each student is then assigned at least one ant lion to care for and serve as a focus
for student research. Students are given the option of taking the ant lions home and
sharing the activity with their parents. This past year students investigated questions
about habitat preference, substrate effects on pits, the effect of rainfall on pit
construction, the effect of temperature on pit construction, and others. Students are
required to maintain a laboratory notebook to record their research. At parent
conferences, I heard from several parents about the effectiveness of this activity.
About Ant Lions
Acquiring ant lions is the limiting factor for this activity. As far I know ant lions are
not available commercially so I have always collected my own. This is not as difficult
as it may sound since once a suitable habitat is located several dozen can be collected
in just minutes. Antlions range throughout the United States. Ant lion larvae
prefer dry, sandy, or loose soils that are sheltered from the weather. Under the eaves
of my house is just such a location and every summer I have about one hundred ant
lion pits along the bare, loose dirt next to the foundation. Other local sites that I can
count on include the dry duff beneath juniper trees and along the sand bars along
the river. You just have to keep an eye out for these intriguing insects and
markdown locations so you can return later. Collecting involves using a spoon or
similar instrument to scoop 1/2 inch of soil from the bottom of the pit. The ant lion
should be in the sample and can be transferred to a tray, pan or cup. Several can be
held, temporarily, in a large 44-ounce, plastic drink cup (I’ve had up to 36 in one
cup) with minimal loss. You’ll have to look hard because they like to freeze and
become very difficult to see. Once you’ve developed a search image you’ll be able to
make them out in the soil debris in the cup. By the way, about one-half of my
students usually can’t find their ant lion. They are sure that they have escaped. I like
to collect about 2 ant lions per student before school starts.
Caring for the critters couldn’t be much easier. They can survive quite nicely without
any food or water for more than a week at a time. Feeding them small ants, wingless fruit
flies, house flies, flour beetles, etc. works nicely.
Holding containers such as cottage cheese containers, small cups, and trays are all
suitable. A proper substrate of sand is best to work with. Even if you caught your ant
lions from dry soil you’ll find that they are easier to work with in a sand substrate. If
your sand has variable grain size this is a productive area of investigation. Fill
whatever container you use with about 1.5 to 2.5 inches of sand. There is no need to
cover the container. Don’t water the sand (unless you wish to investigate the effects
of rain) the ant lions will get enough water from their prey. Adapt with whatever you
have available. Just get the ant lions and you’ll find that this is a truly worthwhile
activity.
Resources
Bernd Heinrich,”In a Patch of Fireweed”, pp 141-151
Sally Stenhouse Kneidel, “Creepy Crawlies and the Scientific Method”, chapter 10.
Though this is targeted at an elementary teacher audience I highly recommend it for
high school biology teachers who are looking for creative ways to incorporate insects
as vehicles for scientific inquiry.