38 



weights due to the diet (Table 8), although pupae from the unfortified 

 diet were numerically lighter by an average of 0.3 mg. This indicated 

 that adults from both treatments were the same size. 



Larval density study. This study was designed to determine whether 

 a minimum number of 0. aenesoens larvae must be present per unit area in 

 order to have maximum development in a minimum amount of time. The 

 fortified diet (Table k) was placed loosely in 360-ml plastic cups to 

 within 5 cm of the rim. Four population levels were used, each repli- 

 cated four times. One cup with media served as a replication. To each 

 cup in the respective treatment group, 5, 25, 50, and 100 first-instar 

 0. aenesoens larvae were added. Larvae were 12 to 18 hr old with an 

 average length of 1.0 mm. After addition of larvae, cups were covered 

 with screen and placed in the growth chamber. Pupal cases were separated 

 from the medium after the emergence and death of the adults. 



Resul ts. The number of adults that emerged when the larval density 

 averaged five larvae per 360 ml of medium was significantly lower than 

 the number of adults that emerged from treatments with higher larval 

 densities (Table 9). The treatment with the lowest larval density 

 averaged kQ.0% viability while treatments with 25, 50, and 100 larvae 

 per 360 ml of medium averaged 91.0, 89.5, and 86. 3% respectively. Results 

 indicate the existance of an 0. aenesoens minimum population density 

 threshold in between 5 and 25 larvae per 360 ml of medium. Additional 

 research is needed to more accurately define the threshold. 



Temperature of larval medium. Two aluminum pans, 25 cm in diameter 

 and 8 cm deep, were filled to within 2 cm of the rims with the forti- 

 fied larval diet (Table k) . One pan was seeded with ca. 500 eggs of 

 0. aenesoens and the other was used as a control . Pans were screen- 



