| Have you ever pondered the mysterious appearance of fruit flies on fruit? The aroma of fruits and vegetables attracts female fruit flies. They lay eggs, usually about 500, on or slightly below the surface of ripening fruits and vegetables. You observe the fruit flies after they emerge from their cocoon and wonder at their baffling appearance. The fruit you may have purchased yesterday might currently have fruit flies on it because of eggs deposited there days before. Female fruit flies laid their eggs in an unsealed puncture in some of the banana jars that we observed in school, fruit flies did not magically materialize in the jars. Although it can appear that something in the fruit or vegetable causes the fruit fly to develop, that is untrue. It is unusual for you to witness the laying of a fruit fly�s eggs so this theory may be difficult to believe. However, experiments have been conducted which have proven this theory correct. An unfamiliar interesting fact about the fruit fly is that the production of a pair of fruit flies in a year would occupy the emptiness between the sun and the earth. Due to their lack of intelligence, it is remarkably simple to capture fruit flies. Few people know how harmful fruit flies can be. The oriental fruit fly is considered to be the most dangerous fruit fly species. They poison over 230 different types of fruit. The eggs deposited by female oriental fruit flies hatch. Then they tunnel through the pulp of the fruit transforming it into a rotten, infested, inedible fruit. If they live in a place known to have oriental fruit flies, humans should be wary of oriental fruit flies and take precautions to prevent their infestation of fruit and vegetables. When fruit flies are able to access the skin of neither fruit nor vegetable, they deposit their eggs near the cover crack of improperly sealed containers filled with fruit or vegetables. Their eggs take only about 30 hours to hatch. The larvae develop in clear liquids of the fermenting fruit or vegetable. They live mainly on yeast for five to six days. A brown casing formed from their previous exoskeleton houses the pupa that is developed from the larva. After mating, fruit flies lay their eggs on fruits and vegetables or near the opening on inadequately sealed packages of fruit. They hatch into larva, going through the first, second, and third instar. They then grow to be pupa in a cocoon. They emerge as adults in the fruit and annoyingly eat and rot the fruit or vegetable. Soon they mate and create more of their unproductive species. The cycle begins again. Including their wings, adults are about 1/8 inch long. They are dully-colored insects with bright red eyes. From the time an egg is deposited until a fully formed fruit fly hatches takes six to ten days. Fruit fly population explosions occur when fruit is ripening, usually in homes. Fish are especially fond of fruit flies and will even jump out of the water to catch them. Fruit flies spread diseases easily. They can survive on many different types of nutrients including sink drain slime, sour mops, fermenting flour or food, even alcohol fumes. After fruit flies become adults, it takes them no longer than two days to mate. If a container filled with fruit material is properly sealed before eggs have been laid and is kept that way until the fruit is consumed, the fruit will never become infested with fruit flies. Cold storage slows fruit flies' life cycle development. In class we made eight observations of rotting bananas enclosed in glass jars. Apparently they were not sealed well enough to prevent the fruit flies from laying their eggs there. My banana jar, number nine, was not a recipient of any fly eggs. Other jars however were honored by the presence of fruit flies. At first I was unaware of the purpose of banana jar observations. Now I know they were the basis of this report. As I have stated, fruit flies, after mating, lay their eggs on fruits and vegetables or near the crack on poorly sealed containers of fruit. Scientifically known as drosophilae, fruit flies hatch into larva, going through the first, second, and third instar. They then become pupa in a cocoon. They emerge as adults in the fruit and annoyingly eat and rot the fruit or vegetable they were born in. The mysterious appearance of fruit flies is not really that mysterious. |
| The Mysterious Appearance of Fruit Flies |
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| 108 Ardsley Road Scarsdale, NY 10583 October 2, 2001 Dear Mom and Dad, In science class, I have recently completed the Tap Water Tour, developed by the LaMotte Company. I worked under the supervision of my teacher, Miss Russo. We need pure water to live. Water quality is important to our whole family because different levels of elements in water can cause stains, bad tastes, corrosion, or can clog pipes. Although we live in Edgemont, our water does not come from Greenburgh; it comes from Scarsdale. All residents of Ardsley Road close to us receive their water from the Village of Scarsdale water source. At school, I performed tests on our water to determine its pH, chlorine, hardness, copper and iron levels. I filled a bag up to a certain level, inserted a tablet into the bag, and shook it. It presently changed color. A pH level between zero and six is acidic. Between eight and fourteen is basic. A pH of seven, such as distilled or most tap water, is neutral. An acidic pH causes corrosion and destroys the pipes in which it travels. Basic water clogs up and forms scale in pipes in which it travels. The pH of our water is eight. Because it is basic, it will form scale and clog our pipes. Therefore, we should purchase and install new pipes every few years. Water from shallow wells tends to have a more acidic pH such as six. Deep well water may have a more basic pH such as eight. City water is usually neutral. Chlorine is not a natural element in water. Many city water treatment plants add chlorine to kill bacteria and germs. Chlorine also controls algae in the water. The sample from our house, which I tested during class, contained no chlorine. An excessive amount of chlorine in water smells and tastes bad. Occasionally it irritates your skin and kills plants and fish. Well water does not contain chlorine. Hardness is a condition of water that can decrease soapsuds and clog pipes. Hard water is water with a high level of calcium and magnesium minerals dissolved in it. Soft water has a low level of calcium and magnesium minerals dissolved in it. The water sample from our house that I tested in class showed that we have soft water. We require twice as much soap to wash our hair in hard water as in soft water. Hard water produces spots on glasses and crusty scale on showerheads, sinks and bathtubs. As opposed to chlorine, iron is an element naturally found in most water. The majority of water has a low level of iron. However, our water sample had no iron at all in it. When there is a high level of iron present in water, the water tends to taste bad. It also leaves an orange stain on sinks, bathtubs, shower taps, and clothes. Both copper and iron are unstable in solution and present only in small amounts. Over time these elements will drop out of solution and will not give a positive test. The reason you take iron pills, Mom, is probably due to the fact that our water contains no iron. Like iron, copper is naturally found in small amounts in most water. No copper was present in our sample of water. Acidic water frequently dissolves the copper off the inside surface of copper pipes. If water contains high levels of copper, it tastes bitter. High levels of copper in the water also leave a blue-green stain in bathtubs, shower taps, and sinks. For the bacteria and nitrates tests, we mixed a liquid with my classmate�s water sample under sterile conditions and let it sit for a 24-hour incubation period at thirty-five degrees Celsius. The intestines of animals including humans are naturally inhabited by harmless bacteria called coliform bacteria. Coliform bacteria help the body function and flourish in animal feces but are not naturally occurring elsewhere. People tend to view them as an indicator of sewage or fecal contamination. Germs called pathogens can cause outbreaks of disease if drinking water is not free of these bacteria. Luckily, they chlorinate town water to purify it and well water seldom has bacteria. In school, we didn�t test every sample for bacteria because of its expense but all the samples we did test were negative for bacteria. Now I know I can safely drink the water at my friends� houses. High levels of nitrates can cause solution problems and lead to excessive algae growth. However, they are necessary for plant growth. In drinking water, a nitrate level above 3 ppm (part per million) can be fatal for children under six months of age. Nitrate levels above 10 ppm can be toxic for adults. Nitrates can leak into ground water from natural eco system run off including from lawns and gardens, leaching from septic tanks, and excessive use of fertilizer or animal manure. If high levels are absorbed into the blood, red blood cells become incapable of carrying oxygen. My classmate�s sample had less than 0.25 parts per million. In conclusion, our tap water has a basic pH of eight, it is soft water and there is no chlorine copper or iron in it. Every few years we should purchase and install new pipes because our basic water forms scale and clogs them. All the samples had a negative test for bacteria and Jason�s water sample had less nitrates than 0.25 ppm. We did not test any water for lead. We could take a basic precaution and run water for a few minutes and use cold water for cooking and drinking, but that would be a pain in the neck. In science class, I performed many water tests. If there were iron or copper in our water, we would need to filter it. I enjoyed testing the water and got better at remembering to take a water sample in the morning. I learned about all the aspects of elements we tested for in water. From, jquantumr |
| Science Water Letter |