Science at Home Series

A Practical Guide for Parents Whose Child Is Fortunate to be in Ms. Ingraham's Honors Biology Class, Mililani High School, 1999-2000
by Ron Kubota
Problem:  How do you help your child to catch live cockroaches?

Background Information:
To teach the students observation skills, Ms. Ingraham requires her honors Biology students to bring to class live roaches for observation.  American or German roaches are very difficult to capture, especially alive.  They move very fast and can also fly.  This is an insect that many people do not want to touch with their bare hands. 

Catching these roaches were quite a challenge one night at our home.  After a number of failed attempts with a scoop net and rubber gloves, we resorted to trapping them.  An open plastic bag with some coke (soft drink, regular, not diet) was left outside and then checked after a short period of time.  One roach was caught in this manner.  A plastic bottled water container was also baited with some coke and left outside uncapped. Another roach was caught this way.  Both the plastic bag and bottle required periodic checking and a quick hand to trap the roach inside.  As a result of this experience, an idea was born.  Why not make a roach trap?

When someone says that for every roach you see, there are probably hundreds that are there unseen.  One reason is that roaches being nocturnal and are most active at night.  A container that will allow the roaches to enter but not leave was needed.  Commercial roach traps do this but these sticky traps render the roaches immobile, making them useless for Ms. I's observation activity. 

A trap was made using common household items.  It worked so well that it was almost unbelievable!  The trap captured  many roaches including some very large wingless juveniles that were first though to be a different species.  Over a few days, one trap captured more than 20 roaches.   In preparing the materials for this demonstration, the first night resulted in two roaches.  Somehow the trap fell over the next night and all of the roaches escaped.  The third night resulted in 6 roaches.  (See photo at the end of the article)

Materials Used
  • Knife
  • Paper Towel
  • Chopstick
  • Pam or Other Non-Stick Cooking Oil
  • Empty Bottled Water Container
  • Sugar
  • Masking Tape
Step 1

Using the knife, carefully cut the bottle as shown below.


Remove the top portion.

Step 2

Lightly spray the inside with the non-stick cooking oil.  Using a piece of paper towel wrapped around the chopstick, rub the inside surface to evenly distribute the oil.  Be careful not to get oil on the outside of the container.  The oil will make the surface slippery so that the roaches will not be able to climb out.

Step 3

Fold a piece of paper towel and put it in the bottle.  Put some sugar in and then add some water just enough to moisten the sugar and paper towel.

Step 4

Invert the cut off portion of the bottle and insert it into the bottle as shown.


Step 5

Secure this inverted portion with tape as shown.

Step 6

Set your trap, preferably against a wall where roaches are known to exist. Roaches captured and left in the trap will attract more roaches.  Be sure to secure it so it won't fall over.

Hope you capture some roaches...


Wingless juveniles on top

A Simpler Idea
Another idea would be to oil the inside of a bottle, bait it, and leave it out overnight.  If roaches are found in it the next morning, simply put the cap on and take your live specimens to school.  Don't forget to put the bottle in a paper bag as not to cause panic and mass hysteria.