478 Phylum Arthropoda 



Family mylabridae 



REARING STORED FOOD INSECTS FOR 

 EXPERIMENTAL USE 



L. Pyenson and H. Menusan, Jr., Cornell University 



IN REARING insects for experimental use it is of great importance to 

 have a large and constant supply of the different stages available. 

 The insects should also remain constant in their reactions to changes in 

 the environment for successive generations. To obtain insects which 

 constantly react in the same way it is necessary to rear them on a uni- 

 formly balanced food in an environment that is maintained constant. 

 The food used should give the greatest growth in the shortest possible 

 time, and the environment (temperature and humidity) should be 

 readily maintained and should allow maximum development in the 

 shortest possible time of the greatest number of individuals. 



The food to use will depend entirely on the species of insect. The 

 optimum environment for stored food insects is a temperature of ap- 

 proximately 30 C. with a relative humidity of from 80% to above 90%. 

 The difficulty of maintaining the humidity above 90% without occa- 

 sional condensation of water on the food (either because of tempera- 

 ture fluctuations or because of metabolic water given off by the insects), 

 with a consequent growth of fungi, renders the higher humidities im- 

 practicable. 



Control of temperature and humidity* is essential since it has been 

 found that these environmental factors affect the rate of growth, size of 

 resulting adults, rate of oviposition, death rate, etc. Other environ- 

 mental factors such as light, air movement, etc., may easily be controlled. 



The control of temperature is satisfactorily handled by a bimetallic 

 thermo-regulator in connection with heating elements made with wire 

 of the desired resistance. The constant temperature box will operate 

 best when placed in a room the temperature of which is about 10° C. 

 below the temperature required. An 8-inch electric fan circulating air 

 maintains the same temperature throughout the box in addition to per- 

 mitting a more accurate control. 



The control of the relative humidity depends on accurate control of 

 the temperature. For most rearing work the humidity may be ap- 

 proximately controlled by placing large shallow dishes of the appropriate 

 supersaturated salt solutions in the constant temperature box. A more 



* For further details of this technique the following references are suggested: 

 Shelford, Victor E. 1929. Laboratory and Field Ecology (Williams and Wilkins 



Company, Publishers, Baltimore). 

 Spencer, H. M. 1926. Laboratory methods for maintaining constant humidity. 



International Critical Tables 1:67. New York & London. 



