Studying Aggression in Drosophila (fruit flies)

Published 2/25/2007
6 Comments
  CITE THIS  SHARE 
Biology

Your institution must subscribe to JoVE's Biology section to access this content.

Fill out the form below to receive a free trial or learn more about access:

Welcome!

Enter your email below to get your free 10 minute trial to JoVE!





By clicking "Submit", you agree to our policies.

 

Summary

Cite this Article

Copy Citation

Mundiyanapurath, S., Certel, S., Kravitz, E. A. Studying Aggression in Drosophila (fruit flies). J. Vis. Exp. (2), e155, doi:10.3791/155 (2007).

Abstract

Aggression is an innate behavior that evolved in the framework of defending or obtaining resources. This complex social behavior is influenced by genetic, hormonal and environmental factors. In many organisms, aggression is critical to survival but controlling and suppressing aggression in distinct contexts also has become increasingly important. In recent years, invertebrates have become increasingly useful as model systems for investigating the genetic and systems biological basis of complex social behavior. This is in part due to the diverse repertoire of behaviors exhibited by these organisms. In the accompanying video, we outline a method for analyzing aggression in Drosophila whose design encompasses important eco-ethological constraints. Details include steps for: making a fighting chamber; isolating and painting flies; adding flies to the fight chamber; and video taping fights. This approach is currently being used to identify candidate genes important in aggression and in elaborating the neuronal circuitry that underlies the output of aggression and other social behaviors.

Protocol

1. Assembling the chamber walls

  1. Take two plain glass slides, mark the middle at the two edges and using a straight edged ruler as a guide, score the glass with the diamond cutter.
  2. Slide the diamond cutter back and forth a few times until you hear a scraping noise.
  3. Wash the glass, and holding it with two paper towels over a broken glass receptacle, apply gentle pressure close to the scored line with the scored side
    facing away from you to break the slide into two halves.
  4. Generously apply the glass adhesive along an edge of one piece of glass and push a second piece of glass against the adhesive at a right angle to the first piece. Place down on a flat surface (aluminum foil, waxed paper or regular paper) and allow to set for at least an hour.
  5. After an hour, repeat the application of the adhesive step to form a square chamber and allow to harden overnight.

    Figure 1

2. Placing the walls in a Petri dish

  1. Take the top of a Petri dish and fill to a depth of at least 5 mm with a heated solution of 2% agarose (microwave the agarose in deionized water until it fully dissolves).
  2. Wait a few minutes, but while still dissolved, place the walls of the chamber in the center of the dish. Take the bottom of the Petri dish, place it bottom side up. Using a flame-heated straight dissecting needle, make a set of small holes (> 1mm) in the center of the dish for ventilation. Make a larger hole (~ 4 mm diameter) slightly to the side for introducing flies to the chamber. Place a piece of removable label tape over the larger hole.

    Figure 2



    Figure 3

3. Making the food cup

  1. Heat a vial of fly food to the point where the food is melted. Use a Pasteur pipette to transfer food to a scintillation vial closures filling it to form a flat surface at the top. Be careful to avoid air bubbles and allow to cool.
  2. Make fresh yeast paste by grinding a small amount of dry yeast and a few drops of water in a mortar and pestle. Add more yeast or water until the consistency is thick enough to allow a small visible drop to be picked up by a toothpick and applied to the center of the food surface.
  3. Place the vial of food in the center of the chamber and place the bottom of the Petri dish, inverted so that the sides are up and not obscuring the view, on top of the chamber. Introduce two 3-5 day old flies by aspiration into the chamber through the larger hole in the top. Cover that hole with tape and place a piece of black filter paper with a 2 cm hole cut in it into the top dish.
  4. Place a desk lamp above the chamber, far enough away that it will not heat the chamber, and positioned so that it will illuminate the food surface. The entire assembly should ideally be placed in an environment with high humidity and a temperature of 22-25°C.

    Figure 4

4. Begin videotaping through front wall of the chamber when both flies are on the foodsurface.

Subscription Required. Please recommend JoVE to your librarian.

Comments

6 Comments

  1. It would be nice to know more about the so called hard-wired "instinct" in organisms. DŒs it go all the way back to the DNA definition of the organism?
    I was amazed at the behaviour change of my dog from a tiny puppy to a grown up dog. Until age 6 months, the dog was quiet and suddenly, around the age of 6 months, the instinct to bark kicked in and the dog started barking at the sight of strangers, What triggered it??
    Also, my dog shows another behavior that makes me wonder. Keep in mind that when this behaviour started, my dog really hadn't played with dirt or had a chance to dig around. Before sitting down, the dog would pretend "dig" whether on a nice comfy bed or on carpet or couch. This behavior is similar to stray outdoor dogs in warm climates where they find a nice damp spot in shade and dig a little before sitting on it to get the cool surface, My dog just started doing that instinctively one day and hasn't stopped. Amazingly, this dog had no experience of the environment where this behavior was beneficial.

    Another one that makes me wonder is the instinct to dig and hide food. My dog one day started this behavior out of the blue as well and it is very annoying because now we find food hidden at different locations and amazingly the dog remembers where this food it hidden. When the dog wasn't hungry and had food left over (let us say a piece of bread), the dog would take it to a corner or near the foot of a table or near any other object on the carpet, sit the food on the carpet surface, pretent to dig a little with front paw (no damage to the carpet, as no real force is applied) and then move the snout in a forward motion on the surface of the carpet as if making a pile from the dirt or leaves to cover the food. Funny thing is that all of this is make believe as there is no dirt or any other material. The dog dŒs it frequently!! This makes me certain that some behavior is not learned from the environment but is part of the instinct and hard wired. It would be cool to know if this hard-wiring code is hidden in DNA as well?

    Reply
    Posted by: Anonymous
    December 20, 2007 - 7:37 PM
  2. Dog behavior should be an extremely fertile field for dissection behavior and the connection to genes. The pressures of artificial selection on dogs by humans has been extremely intense so that not we have situations where rat terriers bred to be rat killers are expected to be cute pets.

    Reply
    Posted by: Anonymous
    February 6, 2008 - 5:15 PM
  3. I'm not really convinced there are many "hard-wired instincts" in animals. Even flies show spontaneous behavior (Maye et. al. ²007), so most likely, all animals produce spontaneous behaviors and as such will always produce "new" behaviors which haven't been there before. Notwithstanding, certain behaviors can appear very stereotyped, even in animals we don't usually consider "hard-wired" at all, such as primates: complex movements such as aggressive facial patterns, defensive forelimb movements, and hand-to-mouth and reaching-and-grasping movements can be elicited as a whole by microstimulation in the brain (Stepniewska et al. ²005).Thus, the behavior of all animals arises from a more or less complex interaction between relatively stereotyped movement patterns, spontaneous variation and feedback from the environment. This has been realized by most behavioral scientists about ²5 years ago, so now the use of the word "instinct" is deprecated for this very reason.Because the interactions between the animal's genome and its environment shape every behavior, the fruit fly Drosophila, with its rich genetic repertoire, easily monitored behaviors and suberbly controllable sensory input is a perfect model system to study how the brain generates complex behaviors. The question of how the brain decides whether or not to be aggressive towards conspecifics can be asked for every single animal species - but Drosophila provides a great study case for getting at the fundamental principles of how brains accomplish this task.

    Reply
    Posted by: Bjoern B.
    February 18, 2008 - 10:26 AM
  4. What is the result of a fight between two winners? What is the result of a fight between a female and a "homosexual" fly? These are questions my posed by my high school biology class.

    Reply
    Posted by: Anonymous
    February 6, 2008 - 3:04 PM
  5. I found the results in the PNAS 103(46) paper.
    Thanks,

    Sam Clifford Round Rock TEXAS

    Reply
    Posted by: Anonymous
    February 7, 2008 - 12:34 PM

Post a Question / Comment / Request

You must be signed in to post a comment. Please or create an account.

Video Stats