In Vivo Intracellular Recording of Photoreceptor Cell Spectral Sensitivity in a Butterfly

Begin with an immobilized butterfly on a platform.

Under a dissecting microscope, insert a reference electrode through the mouthparts to reach the head, and fix the electrode to the platform.

Make a small incision in the cornea and seal it to prevent drying.

Using brief lighting under a stereoscope, position a recording electrode filled with an ionic solution above the cornea.

Then, lower the electrode into the cornea using a micromanipulator to access the photoreceptor cell.

A significant voltage change across the membrane indicates the contact of the electrode with the cell.

Dark-adapt the insect by switching off the external light sources.

Initiate light flashes with a pulse generator and direct a fiber optic cable toward the eye.

Adjust the position of the electrode and fiber optic cable until a depolarizing response is obtained.

Record the cell's responses to white light and colored filters to assess its sensitivity to different light wavelengths.

To prepare the specimen, under the microscope, affix an individual butterfly inside a small plastic tube with hot wax, so the head is immobile and protruding from one end of the tube. Then, affix the proboscis, antennae, and wings wi