Light Spot Assay: A Method to Investigate Drosophila Phototactic Behavior

– Begin by selecting a third instar larva, the largest of the larval forms, from the culture medium, and wash it with water 세스 remove any food. Since the larval eyes, or Bolwig organs, are located in the upper front of the larva, place the larva in the center of an agar plate with the light source above the animal. Turn off the room light and allow the larva 세스 acclimate 세스 the dark.

Since the larva is barely detectable in a light spot made by visible light, turn on infrared LED lights 세스 illuminate the animal for the camera. Wait until the animal begins crawling straight 세스 control for its path. And then rotate the plate so that the larva crawls directly toward the light spot. Record the animal crawling into the light and then away from the light spot. This light-avoidance tactic helps larvae avoid predators by burrowing into food.

In the following example, we will perform the light spot assay 세스 test the ability of different genetic strains of Drosophila larvae 세스 escape light.

– Before introducing the larva 세스 the imaging setup, acquire a short 비디오 of the light position, and 이름 the unfiltered control background 비디오 “lightarea1”. Place the filter back on the camera lens, and turn on a light far from the experimental device at as low a setting as possible while still allowing the larvae 세스 be clearly observed. Use a spoon 세스 remove some larvae from the culture medium, and gently select a third instar larva.

Wash the larva in distilled water, and place the larva in the center of the agar plate. Gently remove any excess water from the larva, and turn off the room light. Allow the larva 세스 acclimate for two minutes in the dark environment before turning on the infrared LED light. The following light-avoidance behavior experiment needs 세스 be carried out in the dark. For the convenience of demonstration, we filmed in the bright light.

Gently brush the larva 세스 the center of the plate. When the larva begins 세스 crawl straight, rotate the plate 세스 make the larva head towards the light spot. Click Capture, Setup, and Video Capture 세스 select the save path. And click Start Recording 세스 record. Allow the lava 세스 crawl toward, enter, and leave the light spot until it is nearly out of the field of view, then click Stop Recording.

Move the filter away from the camera, and acquire a short 비디오 of the position of the light spot. Then 이름 the post as a unfiltered video, “lightarea2”, and compare this 비디오 with the “lightarea1” 비디오 세스 ensure that the light spot position is not changed.