TABLE 2. --Results of a typical experiment showing the relative attractiveness of 

 various levels of "luminous flux density. " 



Order and species 



Number lamps and type 1 



1 - BL 



3 - BL 



4 - BL 



Av. total 



catch per 



night (No.) 



Percentage of total catch 



Lepidoptera: 



Cabbage looper. . . 

 Fall armyworm. . . . 

 Garden webworm. . . 



Bollworm 



Miscellaneous 



Coleoptera 



Hemiptera 



Homoptera: 



Cicadellidae Spp. 



Trichoptera 



Hymenoptera 



Diptera 



All insects 



27.6 



36.5 



35.9 



1,360 



47.9 



31.6 



20.5 



468 



23.1 



43.8 



33.1 



676 



29.8 



33.6 



36.6 



2,055 



40.7 



28.9 



30.4 



2,680 



32.4 



27.2 



40.4 



10,196 



15.8 



36.2 



48.0 



1,987 



24.9 



50.8 



24.3 



1,871 



32.8 



21.0 



46.2 



10,550 



7.7 



73.9 



18.4 



520 



34.9 



28.4 



36.7 



854 



31.2 



29.2 



39.6 



33,217 



1 15 -watt fluorescent lamps. 



Source: Hollingsworth, Texas A. & M. College Plantation, College Station, Tex., August 

 4-11, 1953. 



BACKGROUND OF "INTENSITY" INVESTIGATIONS 



Since the foregoing mention of a possibly untried scheme of study could be inter- 

 preted as an implied criticism of the investigators, the author 'wishes to state definitely 

 that this is not the intention and hopes that a brief examination of the background of 

 investigations of "intensity" will point out why. In the first place, the blacklight ultraviolet 

 sources which are now accepted as being the most effective attractant for most nocturnal 

 insects have been available for only a relatively short time and workers have found 

 investigations of differences in attractance due to wavelength much more rewarding 

 than those involving "intensity" during this period. It is also logical that investigations 

 of the effects of "brightness" and "illumination" should follow determinations of attractive 

 wavelengths. 



Furthermore, studies involving "luminous flux density" and "brightness" become 

 rather complex and are not readily done under field conditions. Characteristics of the 

 output of lamps change with temperature, supply voltage, and duration of use, so it is 

 difficult to maintain stable conditions in the field. Also, individual lamps and their 

 associated circuit elements differ considerably in their output characteristics, so that 

 calibration of components is usually necessary to keep experimental differences within 



29 



