Most foods contain small amounts of insect material or eggs. Common bugs are the red flour beetle, which lives in flour and other pantry food, according to North Dakota State University, in cooperation with the U.S. Department of Agriculture. Other such insects are the Indian meal moth, which lives in spices and nuts, dermestid beetles, which eat plants and meat, cabinet beetles, which eat cereal, and larder beetles, which eat pet food and dried cheese.
Collect different food products to start your experiment. Pantry items would work best for this science fair project. At the grocery store, purchase items such as flour, rice, cereal and nuts. If your store has a bulk item section, purchase some of these items because many insects live in these sections.
Set up the packaged foods separate from your kitchen. First examine the contents of each packaged item for insects or insect pieces. Create slides from the food by adding a pinch of food with a drop of water onto a glass slide and place a cover slip over it. Observe any insects or their parts under a microscope. Record the data. Then place each item into a separate plastic file tote container with a lid, which are found in office supply stores, in a cool, dark spot. You do not want any insects from outside to eat their way into the packaged foods. Wait for one week and examine the contents of each packaged food for any insect growth. It takes one week for adults to emerge for the larva stage in these types of insects, and most of these pests have a life cycle of two months, so this project needs to be at least two months long. Create more slides every week and look for any overall differences. Seal each plastic container again and examine every week for four months.
Collect all your data and be sure to take lots of photographs during the experiment. Many packaged foods such as flour have insect eggs or larva in them but are so small that they go undetected. Your experiment should find some packages with more growth than others. Chart what kind of insects you find, and if you find adults, whether they are eggs or larva. Eggs are round, larva are worm-like and adults are six-legged, with bodies that are divided into three parts. Look for images of the pests on Insect Images (www.insectimages.org/search/action.cfm?q=grain%20weevil) or Penn State's Cereal and Pantry Pests page (ento.psu.edu/extension/factsheets/cereal-and-pantry-pests). Place all of the information on a science fair display board.