GMU:Habitats SS18/Drosophila

Physical appearance

“Wildtype fruit flies are yellow-brown, with brick-red eyes and transverse black rings across the abdomen. They exhibit sexual dimorphism: females are about 2.5 millimeters (0.098 in) long; males are slightly smaller with darker backs. Males are easily distinguished from females based on colour differences, with a distinct black patch at the abdomen, less noticeable in recently emerged flies, and the sexcombs (a row of dark bristles on the tarsus of the first leg).”(wikipedia)

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  Female (left) and male (right). Source: Wikimedia

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Song simulator

File:Main-20161025_2.maxpat

Lifecycle and reproduction

“The life cycle of this insect has four stages: fertilized egg, larva, pupa, and adult.”(wikipedia)

“The Drosophila melanogaster lifespan is about 30 days at 29 °C. .. The shortest development time (egg to adult), 7 days, is achieved at 28 °C .. Under ideal conditions, the development time at 25 °C is 8.5 days, at 18 °C it takes 19 days and at 12 °C it takes over 50 days .. Females lay some 400 eggs (embryos), about five at a time, into rotting fruit or other suitable material such as decaying mushrooms .. The eggs, which are about 0.5 mm long, hatch after 12–15 hours .. The resulting larvae grow for about 4 days (at 25 °C) while molting twice (into second- and third-instar larvae), at about 24 and 48 h after hatching. During this time, they feed on the microorganisms that decompose the fruit, as well as on the sugar of the fruit itself. The mother puts feces on the egg sacs to establish the same microbial composition in the larvae's guts which has worked positively for herself.”(wikipedia)

Model organism

D. melanogaster is one of the most studied organisms in biological research

• Its care and culture require little equipment, space, and expense
• It can be safely and readily anesthetized (e.g. by cooling)
• It has a short generation time
• It has a high fecundity (females lay up to 100 eggs per day, and perhaps 2000 in a lifetime)
• Males and females are readily distinguished
• Similarity to humans (60% of genes are conserved between the two species)

(wikipedia)

Medium

• Homemade Fruit Fly Culture Media
• Himedia medium

“Dried Brewers yeast supplies vitamin and amino acid mixture for the growth of Drosophila. V-8 vegetable juice serves as a source of essential nutrients such as magnesium and potassium ions. Corn meal provides fructose as main carbohydrate source for cell proliferation. Low pH of the media will help to suppress bacterial growth and methyl parahydroxybenzoate serves as inhibitor for bacterial and fungal contaminants”(HiMedia)

Variation, use the following ingredients

• 1 cup banana (about 2 bananas)
• 1 cup apple sauce
• 1 Tablespoon vinegar
• 2 cups oat meal

Tracking Drosophila

• Kristin Branson et al (2009). "High-throughput ethomics in large groups of Drosophila," in Nature. Available at https://www.nature.com/articles/nmeth.1328.pdf (accessed: 2 May 2018)

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  Schematic diagram of the walking arena. A 24.5 cm tall printed paper cylinder is backlit by an array of 8 halogen lights. Source: Branson et al (2009)

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  Differences within and among individual flies. (a) The first and second halves of trajectories for three male and three female flies. Source: Branson et al (2009)

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References

• HiMedia Laboratories. “Drosophila Medium.” Available at http://himedialabs.com/TD/M224.pdf (accessed: 2 May 2018)
• Wikipedia. “Drosophila melanogaster.” Available at https://en.wikipedia.org/wiki/Drosophila_melanogaster (accessed: 2 May 2018)
• Kristin Branson et al (2009). "High-throughput ethomics in large groups of Drosophila," in Nature. Available at https://www.nature.com/articles/nmeth.1328.pdf (accessed: 2 May 2018)