This technique was used in studies with the eyes of the dark-adapted grasshopper 

 Melanoplus (4) and the silk moth Samia cecropia (13). When using equal intensities of 

 incident energy, the wavelength with the greatest stimulation efficiency was found to 

 be in the green region (530 m/i) with blue, violet, orange-red, and red (in order) of 

 decreasingly less effectiveness. Ultraviolet wave bands were not included in these 

 studies. Their general conclusions were that differences in ERG wave forms were due 

 purely to intensity differences and that by properly adjusting the intensity of the different 

 colors, the electrical response to different wave bands could be exactly matched. They 

 also pointed out the similarity between the response curves obtained (a peak in the green 

 region with sharp decline toward the red and a less sharp decline toward the violet) and 

 the absorption curve of visual purple (rhodopsin) and the behavior curve of the fruitfly 

 Drosophila. 



Similar work was done with the king crab Limulus (15). The effect of various wave- 

 lengths of energy in the visual spectrum was evaluated for single visual sense cells. 

 With light of equal energy content the strongest response was found to occur in the 

 green region of the spectrum atSZOm^. The response curve determined was symmetrical 

 about the maximum of 520 mix and, as the authors point out, closely resembles the visi- 

 bility curve for human rod vision (dark-adapted eye). No Purkinje effect (shift in response 

 toward the red end of the spectrum) could be observed even with intensities varying in 

 ratios up to 100:1. These workers also concluded that the response did not vary quali- 

 tatively with wavelength because, by proper adjustment of incident energy levels, iden- 

 tical responses could be obtained for all of the different wavelengths tested. 



Extensive examination of literature in this field has failed to reveal similar work 

 with night flying insects. However, such information may evolve from work now under 

 way by Mr. James Stanley, A.R.S., U.S.D.A., located at Virginia Polytechnic Institute, 

 Blacksburg, Va. Mr. Stanley is currently studying the response characteristics of the 

 tobacco hornworm moth ( Protoparce sexta (Johan)) to equal energy, narrow wave band 

 radiation by the use of kymographic equipment and techniques. 6 



Studies by the Group Motor Response Technique: Group motor response studies include 

 laboratory and field determinations of the relative effectiveness of the various regions 

 of the spectrum as evaluated by the numbers of insects of a particular species responding 

 to a radiant energy source when energy from the source is presented to relatively large 

 insect populations of either known or unknown exact magnitude. Methods employed and 

 equipment used for making such studies have varied widely. 



FIELD STUDIES 



The electric insect trap has been the basic tool for field studies of this nature. 

 Conclusions with regard to the effectiveness of various wavelengths have been made 

 with reference to the spectral characteristics of the energy radiated by the lamps used 

 in the traps. 



Gui, et al. (11) made a rather comprehensive study of the relative attractiveness of 

 different colored tungsten lamps in connection with research to determine lamps that 

 were not attractive to insects. They found that all of the different colored lamps tested 

 would attract insects to a greater or lesser degree and that the order of attractiveness 

 (from greatest to lowest) was blue, white, yellow, and red. No ultraviolet lamps were 

 included in these tests. Attractiveness of different colored incandescent lamps to certain 

 species of mosquitoes was tested at Ft. Benning, Ga., in 1955 (1). 



6 Stanley, J. M. Monthly Activity Reports for 1959. (Copy on file Farm Electrification Research Branch, Agricultural Engineering 

 Research Division, ARS, USDA, Plant Industry Station, Beltsville, Md.) (Unpublished) 1959. 



11 



