Database Reference
In-Depth Information
1: WEEKLY L T B
2: WEEKLY N T B
3: N
1:
900.00
2:
300.00
3:
60.00
1
1:
450.00
2:
150.00
3:
30.00
3
1
1
1
3
3
3
2
2
2
2
1:
0.00
2:
0.00
3:
0.00
0.00
208.00
416.00
624.00
832.00
Fig. 7.10
WEEK COUNTER
DEER MODEL FOREST
WEEKLY ADULT TICK BURDEN DEER
TICK PER DEER PER DAY
Fig. 7.11
Additionally, we assumed that deer were host to approximately 30 adult ticks
per day. Since the feeding period for an adult female is 7 days, we assumed 30 adult
ticks per week on a deer (Figure 7.11).
Figure 7.12 shows the seasonal variation in adult tick burdens in our 1-hectare
forest.
The population dynamics of the blacklegged tick illustrate the two different pop-
ulations that are active during particular seasons (Figures 7.13 and Figures 7.14).
We assumed that the ticks cannot immigrate or emigrate from the model (or im-
migration = emigration). In nature, ovipositing and egg development are based on
cumulative degree days. In lieu of good data on which to model temperature de-
pendence, we approximated the development of eggs by employing a sine wave
function. Average area under the curve is equal to the average success of hatching,
and length (in weeks) is appropriate to the occurrence of hatching in the wild.
Ticks move in sequential fashion from egg to larva, to nymph, to adult during
a 2-year period in which they are in resting stages prior to molting to the next
