Dec. 15,1924 Tobacco Flea-Beetle in Southern Cigar- Wrapper District 583 
While tobacco is the preferred food 
plant of the tobacco flea-beetle, many 
other plants, wild and cultivated, be¬ 
longing to the Solanaceae are fed 
upon to a considerable extent. In the 
absence of solanaceous plants, the 
beetles will feed sparingly upon various 
other wild and cultivated plants. 
Preoviposition period. —On May 
8, 1921, two adults emerged from pupal 
cells and were immediately transferred 
to an oviposition cage. On May 23 
the first eggs were deposited, giving a 
preoviposition period of 15 days. 
Again, on June 25, 1922, six tobacco 
flea-beetles, which had just emerged 
from their pupal cells, were placed in 
an oviposition cage. No eggs were 
deposited in this cage until July 17, an 
interval of 22 days. Other experi¬ 
ments also bear out the fact that there 
is a period of about two to three weeks 
after emergence from the pupal cell 
before eggs are deposited. 
Oviposition period. —Deposition of 
eggs seems to begin very soon after 
emergence from hibernation. Indeed, 
if the weather is mild there are indica¬ 
tions that a few scattering eggs may 
be deposited through the winter. At 
least one record has been obtained of 
eggs' deposited on February 3. 
From the middle of March to late 
summer deposition is fairly constant. 
The number of eggs laid may fluctuate 
more or less, judging from the appear¬ 
ance of the different generations, but 
since to a certain extent the generations 
invariably overlap, some eggs are 
always being deposited. After the 
tobacco is harvested, however, flea- 
beetles gradually become very scarce. 
There seems to be little activity in late 
summer or early fall, and after the 
beginning of September the deposition 
of eggs seems nearly to cease. 
Proportion of sexes. —Of 407 over¬ 
wintered beetles collected in early 
spring at Quincy, Fla., in 1922 and 
1923, 68 per cent were females and 
32 per cent males. In 1922, of 500 
beetles of the spring generation col¬ 
lected in the field, 65 per cent were 
females and 35 per cent males. Of 500 
beetles of the first summer generation 
collected during the same season, 52 
per cent were females and 48 per cent 
males. These data show a predomi¬ 
nance of females over males, especially 
in the overwintering and the spring 
generations. 
Mating. —Mating was commonly 
observed at all hours of the day. Just 
how much time elapses between emer¬ 
gence of the adult from the pupal cell 
and the act of mating is not known, but 
it is probable that mating occurs during 
the first week. 
Although several attempts were 
made, no eggs were obtained from 
unfertilized females. 
Dispersion. —The tobacco flea- 
beetle utilizes all three of the common 
methods of locomotion — crawling, 
jumping, and flying. Perhaps most of 
the movement from plant to plant in 
the field is done by the first two of 
these methods, but the flea-beetle is 
quite capable of sustained flight. 
Seed-beds have been known to become 
infested with this pest when the bed 
was located in the midst of heavy 
timber a mile from where any tobacco 
had been planted previously. When 
a seed-bed is located near a tobacco 
shade, beetles migrate readily from the 
bed to the shade. Numerous records 
have been made of the collection of 
this beetle on fly-paper screens 5 and 6 
feet above the ground. It is scarcely 
conceivable that the tobacco flea-beetle 
should be capable of flying many miles, 
but that they can and do fly several 
hundred yards is unquestionable. 
Longevity. —Just how long a to¬ 
bacco flea-beetle may live under normal 
conditions is largely a matter of con¬ 
jecture. In the field the overwintered 
beetles have largely disappeared by the 
end of April. With the exception of 
the overwintering individuals, however, 
the average length of life under field 
conditions appears to range approxi¬ 
mately from 40 to 50 days. Laboratory 
records obtained over a period of several 
years indicate that the average length 
of life in confinement somewhat closely 
follows that in the field. 
Several records have been obtained 
of a few flea-beetles living for an ab¬ 
normally long time. In one case where 
200 overwintered beetles were placed 
in confinement April 1, the last beetle 
died August 14. Of another lot of 
adults placed in confinement about 
the middle of March, the last individual 
died July 5. In a third instance, 200 
freshly-emerged adults of the spring 
generation were placed in confinement 
April 17. The last individual died 
September 25. This beetle had a 
definitely known longevity of 161 days. 
These records show that it is possible 
for a few individuals of one generation 
to live so long that their lives overlap 
two following generations. 
Number of generations. —There 
are usually four fairly well-defined gen¬ 
erations in the region of Quincy, Fla.: 
The overwintering generation, which 
generally appears about the time to¬ 
bacco plants are up in the seed-beds; 
7582—25f-2 
