A Little Bit More
The reason these tiny fruit flies are so important to science is the fact that they have giant chromosomes in their salivary glands that makes it easier for use in genetic studies. The public may not be aware of this usefulness to scientists but it is more than aware of their presence on ripe fruit every summer.
The reason fruit flies invade our homes is their interest in fresh and fermenting fruits. These flies both feed on fruit, as well as, lay their eggs near a variety of this kind of material. A single female fruit fly can lay 500 eggs near fruits, garbage, vinegar, juices, and even baked bread. The eggs hatch in 24 to 30 hours, the larvae (maggots) feed for 5 to 6 days, pupate, then emerge as adults ready to reproduce themselves in just two days. It doesn’t take great math skills to realize that fruit fly numbers can escalate quickly each summer. As adults, fruit flies have been known to travel over 6 miles within 24 hours so the flies in your kitchen may very well have come from a neighbor or the surrounding countryside – don’t assume you brought them in from the grocery store on their fruit.
Activities
Science – Fruit Flies
Objectives: See the life-cycle of an insect
Materials: Fresh fruit, plate
(CAUTION: You may need to get permission from principal or custodian to perform this exercise)
This is a simple enough exercise that should be fun and educational to participate in. If it is late spring or summer, you should be able to encourage some nearby fruit flies to visit your classroom.
Put out some cut fresh fruit (juicy fruits like peaches and plums may be best) on a plate or tray in an open area near a window. Allow the fruit to stay there for several days and watch to see if it attracts any fruit flies. Obviously, the flies will have to be able to get into the classroom somehow but more often than not, they do accomplish this in our homes.
If you do see some flies feeding on the fruit, watch them quietly and keep an eye out for any eggs (these will be minute) that they may lay. Even if you don’t see any eggs, you may see some of their larvae feeding on the fruit. Keep an eye on the larvae and once they advance into their pupal stage, you can take the entire setup outside so they won’t end up in your classroom (you don’t want the other teachers to be upset with your “pets”)
Key Concepts
Growth and Development, Identification, Life Cycles, Scientific Method/Approach
Questions
Do you have a question for a naturalist? Go ahead and ask!
It's easy -- just fill out this form, submit your question and you'll receive an answer shortly.