100 
aa re) re.) 
Oo ie) Oo 
PER CENT OF COTTONTAILS INFESTED 
nm 
oO 
PER CENT 
\ AVERAGE NUMBER 
ee ee Oo” 
— 
—<- 
nm oO aS oO 
Oo e) Oo Oo 
AVERAGE NUMBER PER INFESTED COTTONTAIL 
fe) 
_ 
Fig. 10.—Monthly distribution (per cent of rabbits infested and average number on infested rabbits) of Cediopsylla sim- 
plex in Lee County, 1952-1954. The graph is based on 3-month sliding scale of data in table 3. 
It is interesting to compare the apparent seasonal 
fluctuations in populations of this flea with populations 
of other species. Evans & Freeman (1950), in a survey 
of small mammals occurring near Oxford, England, 
found that: ‘‘For each species of host, the monthly 
indices point clearly to a rise, not only in the number 
of fleas per host, but also in the numbers of hosts in- 
fested, during the spring, with a maximum reached in 
the summer and a subsequent decline to a winter low. 
Such seasonal variation has been observed repeatedly, 
yet it is by no means clear how much this is due to a 
real decline in the numbers of fleas present inthe breed- 
ing environment (the nests and burrows of the hosts), 
how much to a decrease in flea activity, or how much 
to changes in the numbers or activity of the host popu- 
et al. (1951) reported 
marked seasonal fluctuations in two species of fleas in 
lation.’” Recently, Holdenried 
California which have the same mammalian host. They 
found that the peak of abundance for one flea was in 
summer and the peak for the other was in winter. 
Whatever may be the reason for the apparent abrupt 
increase in numbers of the common eastern rabbit flea 
on rabbits in Lee County in spring, the time of increase 
coincides, perhaps significantly, with the main breeding 
season of rabbits. Presumably, more occupied rabbit 
nests are present in spring than at any other time of 
year, a condition which is favorable for the development 
of a maximum number of larval fleas. 
13 
