414 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1958 
Table 2 shows the theoretical population trends when an insect 
population is assumed to be stable—that is, when one generation in the 
absence of special control effort would result in equal numbers of 
progeny in the next generation. The example also assumes that the 
ratio of two sterile to one fertile insect will result in a maximum theo- 
retical reduction in progeny. The figures show that a rapid and 
dramatic decline in an insect population is theoretically possible. It is 
realized that the maximum decline can hardly be expected in most 
situations. However, calculations indicate that if only 25 percent of 
the theoretical decline were achieved the end result would still be 
eradication after about seven generations. 
TABLE 2.—Theoretical population decline in each subsequent generation when a 
constant number of sterile males are released among a natural population of 1 
million females and 1 million males 
Number of un- | Number of sex- |Ratio of sterile} Assumed per-}| Theoretical 
Generation mated females |ually sterile males|to fertile males} centage of fe- number of 
in area released competing for |males mated to} fertile females 
each female | sterile males 
— ee ed 
| Pmoeiiemaia ti tahe 1, 000, 000 | 2, 060, 000 
2:1 66:7 333, 333 
ae EA eae 333, 333 | 2, 000, 000 6:1 85. 7 47, 619 
SirAteeP RRO 47,619 | 2, 000, 000 42:1 97.7 1, 107 
EEN lies oe 1,107 | 2,000,000] 1, 807:1 99. 95 () 
1 Less than 1, 
FURTHER RESEARCH POINTING TO SCREWWORM ERADICATION IN THE 
SOUTHEASTERN UNITED STATES 
Following the success on Curagao, the Florida Livestock Board 
urged further research to adapt the method for an eradication 
program for the Southeast and contributed funds to the effort. Addi- 
tional funds were appropriated by Congress to further support the 
expanded research program. The Insects Afiecting Man and Animals 
Research Branch, under the direction of A. W. Lindquist, assigned 
additional members of the research staff to the project. Emphasis 
was placed on efficient and economical methods of rearing the millions 
of flies that would be needed for an eradication program, involving an 
area of 50,000 square miles or more. A small pilot plant having the 
capacity to produce 2 million flies per week was constructed. Mass 
rearing methods were developed utilizing various types of media and 
rearing facilities as well as methods of handling the brood colony of 
flies to obtain the maximum number of eggs. Procedures were devised 
for irradiating large numbers of pupae, and for their proper care until 
adult emergence was completed. Equipment for dispersing the flies 
from aircraft was designed. 
There was little precedent to follow in developing the various pro- 
cedures required for such a program. Every operation required new 
techniques, new facilities, new equipment. Credit is due each and 
