The number of females recaptured was low, and the correlation between trap 
distance and catch was again not significant. The data for males are shown in 
figure 2. The numbers of moths recaptured fell off sharply with increasing 
distance from the point of release and the rate of decline was constant. By 
substituting appropriate values in the equation, it can be calculated that the 
number of P. sexta males recaptured was reduced 50 percent, with each 0.61 mile 
of increasing trap distance. P. quinquemaculata was reduced the same amount in 
1.80 miles. Thus, P. quinquemaculata males traveled farther than P. sexta 
before they were lost. The greatest distance that hornworms were known to 
travel was 6.3 miles for two P. sexta males and one P. quinquemaculata female in 
1961 and 8.1 and 8.2 miles for two wo P. sexta males in glee 
LENGTH OF LIFE OF RELEASED MOTHS 
If it is assumed that the catch of marked moths on successive days after 
release is proportional to the number remaining within the area covered by traps, 
then the rate of disappearance of marked moths can be estimated from recapture 
data. The data for P. sexta males are shown in figure 3. Curves for the other 
species and sexes are similar. 
The regression equations for all groups are given in table 6. By substi- 
tuting appropriate values of y in these equations, the time required for the 
numbers recaptured to be reduced by half, or the half life of released moths, 
can be calculated. These are also given in table 6. Females of both species 
lived longer or remained in the area longer than males. P. sexta males disap- 
peared faster than P. gquinquemaculata males, but the reverse was true of females. 
TABLE 6.--Regression of number of marked hornworm moths recaptured in 
light traps on number of days after release, Aug. 19- 
Sept. 25, 1961 
Probability 
Calculated 
half life 
Species and sex Regression equation 
P. sexta; 
Male--------- < 0.001 a ale 
Female------- De Oi. i Omdsls x <i (On 2.74 
P. quinguemaculata 
Male--------- V6) =) OeLOux Zu 300% 1.59 
BASES Ol = Oe Lax <0 eliuh 
- 10 = 
