Ward's World Working with Guides

+ ward ' s science 5100 West Henrietta Road • PO Box 92912 • Rochester, New York 14692-9012 • p: 800 962-2660 • wardsci.com Captive Care Habitat: Any escape-proof container with holes for oxygen exchange (we use plastic vials with foam tops). Drosophila should be kept at room temperature (65 – 75°F). Care: Food: Drosophila will eat many different fruits and vegetables. The simplest is just a slice of banana. Many different types of culture media have been developed. Each formulation has benefits and shortcomings. In order for a medium to be useful, it must be solid and dry enough so the adult flies do not stick to or drown in, yet moist enough to provide water and it must inhibit the growth of ubiquitous environmental mold. Subculture when media (38 W 0592) is depleted, drying out, or has developed mold. Provide about an inch of dry media at the bottom of the culture vial (18 W 4956), and about 15 mL of water. Information Method of Reproduction: Sexual. Male inseminates female for internal fertilization and the female then lays eggs, about 100 per day. The sperm received by a female fly during mating is retained, serving to fertilize a number of eggs. Therefore, in an experimental cross between two different strains, virgin females must be used to insure that the expected genetic cross produces the resultant eggs. NOTE: Since females do not become sexually mature for about 10 hours, virgin females can be collected within 10 hours of removing all adult flies from a culture with pupae. Virgin flies may lay eggs, but they will not hatch. Life Cycle Development time is influenced by both temperature and strain. At room temperature, it takes about 24 hours for an egg to hatch into a larva. The larva feeds as it burrows through the medium. As the larva grows, it undergoes two molts so that the larval period consists of three stages (instars), the first instar being the newly hatched larva. The first two instars last about 24 hours each. The final larval stage or third instar lasts about 48 hrs and the larva may attain a length of 4.5 mm. Towards the end of the third instar stage, the larva will crawl up the sides of the culture jar, attach itself to a dry surface (the jar, filter paper, etc.) and form the pupa. After about four days in the pupal stage, an adult fly emerges. Females become sexually mature 8 – 10 hours after emerging from the pupae. Adults will live for about 30 days. Wild Habitat Many different species of Drosophila are present throughout the world. Drosophila melanogaster is primarily used for genetic studies for a variety of reasons. Its entire genome has now been sequenced. In the wild, Drosophila melanogaster is thought to have originated in tropical regions of the eastern hemisphere. They can now be found throughout the world with the exception of the arctic. Drosophila are pests that infest rotted fruits and fruits that are beginning to rot. They are also attracted to vinegar and wine. Drosophila can destroy harvested crops in storage. They are food for hummingbirds, frogs and reptiles. Disposition We do not recommend releasing any laboratory animal into the wild, and especially not insects that are considered to be pests or not native to the environment. Adoption is the preferred disposition for any living animal. If the insects must be euthanized at the end of study, follow one of these procedures: • Put them into a container or bag and freeze for 48 hours. • Place the organism in 70% isopropyl alcohol for 24 hours. • Autoclave the organism @ 121°C for 15 minutes. • A deceased specimen should be disposed of as soon as possible. Consult your school's recommended procedures for disposal. In general, dead insects should be handled as little as possible or with gloves, wrapped in an opaque plastic bag that is sealed (tied tightly) before being placed in a general garbage container away from students. © 2021 Ward' s Science. All rights reserved. Rev. 2021

• Cover