Many students view science as a body of knowledge. As something that can be taken off a shelf. Some
of them see it as an activity that only elderly men, wearing glasses and lab-coats can perform. Once
students become aware that science and the scientific method are actions that most of us do daily, they are
more apt to "do" science for us. This lab operates as an effective introduction to scientific inquiry, starting
with a question about the environment and leading students through the scientific method without using
intimidating terminology. In this activity, students discover antlions. Some of us know antlions by their
alias doodlebugs, the curious little creatures that dig pitfalls in sandy areas and flick sand when disturbed.
Antlions belong to the insect order Neuroptera--"nerve wings" or "net wings"--that includes lacewings,
mantispids, snake flies and dobsonflies. They are the predacious larvae of an adult form resembling a
damselfly. The name antlion probably originated from the Greek roots "myrmex" (ant) and "leo" (lion)
derived from the family name Myrmeleontidae,. Antlions exhibit complete metamorphosis, the larvae
being much better known than the nocturnal adult. Many larvae dig conical pits to trap small insects.
They wait hidden at the base of the funnel, with immense jaws to grab any insects that fall into their pit. If
an insect tries to escape, the antlion will flick sand to the edge of its pit, causing an avalanche to hasten the
fall of its prey. Antlions are distributed throughout the United States, particularly in the southwestern
states. They are typically found in sandy soil sheltered from rain, especially next to buildings and under
eaves. On my campus we found a few dozen under the overhangs in front of our school and several
hundred were found beneath the trailer classrooms behind our main building. I use a plastic spoon to
scoop out the entire trap, antlion and all, and then add extra soil from the site to a depth of 3-5 cm. I
place one antlion in each container, which can be a small beaker, or plastic cup or whatever I have on
hand. I prefer 100mL beakers or clear plastic cups for observational purposes.
I have not found antlions commercially available, so they will have to be field collected. It is advisable to
collect antlions the day preceding the lab, to ensure that they build their concave traps in their containers.
You may want to keep some extra cups with formed funnels at your desk for observation, as some
students may accidentally disrupt their pit before they even notice its existence. Often, when their pits are
disturbed, the antlions will immediately begin rebuilding, and the students will get to observe the interesting
sand flicking behavior. Although antlions have large poisonous jaws for capturing prey, they pose no
threat to humans and are easily and safely handled by students. (Since the publishing of this activity in 'The
Science Teacher', i have seen Carolina Biological offer antlions in their catalog)
You may want to make a greater variety of tools available to your students for their initial observations.
Small paint brushes can also be helpful for moving soil and transferring antlions to the paper. Sometimes
antlions "play possum" and students may think that they are dead, especially when they lay on their backs.
Gently blowing on them usually encourages them to right themselves and move around. We have also
noticed an interesting phenomenon. In the wet-dry soil test, antlions first go the wet soil, but then turn
around and bury themselves in the dry soil, so make sure students record which soil the antlion buries its
self in, and not which one it chooses first. You may want to provide time limits for various sections of the
lab, in order not to spoil the surprise of what has constructed the hole, and what an antlion looks like.
This lab takes two full 50 minute periods, part I to be performed on the first day and part II on the second
day.
Antlions are most active during late spring and summer months, however I have found them to be active
on my Georgia campus throughout the fall and into winter. With my general level students I use this
investiagtion in the fall as an introduction to the scientific method. This lab was designed with minimal use
of terms associated with the scientific method. I it intended to harness students' natural curiosity, and to
get them to perform science skills that are innate to humans. Post lab discussions can assign terms to the
various parts of the lab, so students can see that they hypothesized, proposed experiments, and drew
conclusions naturally. Teachers might want to have a dictionary on hand to help define terms like
subterraneous, anterior and posterior for general students.
I vary this antlion activity with my advanced students. I have them perform this investigation in the late
spring after researching antlion classification, habitat, lifecycle, behavior etc. Students are to gather
enough information about antlions to perform an experiment using them. After researching preferred
habitats, I send students to search for and collect antlions on campus--always providing direction
assistance for those who absolutely can't find any. Then for 2 days, students explore their authentic
questions about antlion food, color and light preference, pit construction, distance between pits and
distance able to flick sand. Students then write an article on their findings for peer review.
Once we have studied our antlions, we return them unharmed to their place of capture. Sometimes
antlions can spend years in their larval forms, so I have not tried to keep them through pupation. Now
that students know what antlion pits looks like, it's amazing how many of them will find them around their
homes, jobs and daily pathways. They have now become more aware of clues in their environment.
Whether I use antlions to acquaint students with or reinforce the scientific method, students have a roaring
good time.
Resources
Swanson, Mark. Copyright © 1996-1999. The Antlion Pit: A Doodlebug Anthology. Official web site
address: http://www.enteract.com/~mswanson/antlionpit/