Chapter III 



CULTURE 



Habrobracon juglandis has proved to be ex- 

 cellent material for laboratory study and re- 

 search investigations because of the ease with 

 which it can be handled, the low cost of feed- 

 ing the stocks, and its brief ten-day genera- 

 tion period. These factors together with its 

 fecundity make possible the accumulation of 

 large numbers of progeny in a short time. 



Habrobracon is cultured in shell vials, twen- 

 ty millimeters by seventy millimeters, plugged 

 with cotton covered with fine mesh cheese-cloth 

 through which neither caterpillars nor wasps 

 will burrov/. When the wasps are cultured in 

 this manner it is possible to observe the mat- 

 ing procedure and the complete life cycle. Af- 

 ter mating, the female is given one caterpillar 

 of the host, Ephestia kuehniella, and incubated 

 at 30° C. After stinging the caterpillar the 

 female sucks juice from the puncture but depos- 

 its no eggs until her victim has become torpid. 

 Young females are given only one caterpillar at 

 first because they do not always sting immedi- 

 ately, and the caterpillars, if not stung, start 

 to spin webs upon exposure to incubator temper- 

 atures. The caterpillars may in this way es- 

 cape being stung by the wasp, or the wasp may 

 become trapped in the web and be killed by the 



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