SECTION HI-ROLE OF LIGHT TRAPS 

 IN MEETING INSECT PROBLEMS 



LIGHT TRAPS FOR DETECTION 



Perry A. Glick 1 



INTRODUCTION 



Observations and studies of insect response to light were made as early as 1856 by 

 Belchard. It is probable, however, that no definite collections of insects using trapping 

 devices were made until about 1886. Traps were used before 1904 by Vosseler, as re- 

 ported by Busck (1917). Before 1906, Maxwell- Lefroy used light traps for detection of the 

 pink bollworm moth. 



My first experience with a light trap was in 1914. During the summer of that year 

 a prominent collector of Lepidoptera, A. F. Porter of Decorah, Iowa, visited me at my 

 old home in Missouri. Using a light trap, he had made several collecting expeditions 

 in the head-hunting regions of the Amazon. His trap was unidirectional, using a small 

 carbide lamp equipped with an autolight reflector, and the regular cyanide jar for 

 collecting the specimens. The trap was quite effective, although mostly species of moths 

 belonging to the families Arctiidae and Phalaenidae were collected. 



Continuing from the early part of the 20th century, references to light traps in- 

 creased considerably. When electric lamps, emitting radiant energy in the near ultra- 

 violet and visible regions of the electromagnetic spectrum, -were found more effective 

 in attracting most nocturnal insects, light-trap design became greatly modified. The 

 number of insects and species taken greatly increased, until it was possible and practical 

 to make seasonal surveys and records of insects, particularly those of economic im- 

 portance. 



It appears that a single 15-watt black-light fluorescent lamp is preferable for gen- 

 eral use. The argon lamp is more selective, attracting a smaller number of Orthoptera, 

 Coleoptera, and aquatic Hemiptera, thus allowing the microlepidoptera to be easily 

 examined. This type of lamp is being generally used for pink bollworm detection. 



If a given species is known to be phototropic to the type of lamp used in a light trap 

 and is not taken in the trap operated throughout the year in a specific locality, it may be 

 assumed that the species is not abundant or does not occur. If the species is known to 

 occur and to be rare, the chances of taking the insect may be small, especially if the 

 trap is not properly located. 



THE USE OF LIGHT TRAPS 



Light traps serve as an important and valuable method in collecting crepuscular 

 and nocturnal insects for taxonomic purposes, for detection of the presence of insect 

 pests, to determine population changes or trends, and to aid in predicting potential 

 infestations. 



i Entomologist, Entomology Research Division, Agricultural Research Service, U. S. D. A., Brownsville, Tex. 



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