Database Reference
In-Depth Information
1: ACORN MAST INDEX
2: DEER MODEL FOREST
1:
200.00
2:
30.00
1:
100.00
2:
15.00
0.00
2
2
2
2
1:
1
1
1
1
2:
0.00
0.00
208.00
416.00
624.00
832.00
Fig. 7.8
DAILY LARVAL TICK BURDEN
WEEKLY LARVAL TICK BURDEN
WEEKLY LARVAL TICK BURDEN MICE
~
N
WEEK COUNTER
WEEKLY NYMPH TICK BURDEN MICE
~
DAILY NYMPH TICK BURDEN
WEEKLY NYMPH TICK BURDEN
Fig. 7.9
WEEKLY LARVAL TICK BURDEN
=
N
∗
DAILY LARVAL TICK BURDEN
∗
7
/
4
(7.2)
For a daily larval tick burden of 5 larval ticks and 20 mice, 175 larval ticks could
successfully feed per week (instead of 700 for a 1-day feeding time). The same
mathematical assumption was applied to the weekly nymphal tick burden per mouse
(Figure 7.9).
Figure 7.10 displays the relationship between mouse population density and the
weekly larval and nymphal tick burdens. Note the seasonal distribution of nymphs
and larvae. We used this seasonal information to regulate the appearance of unfed
larvae and unfed nymphs. Although we omitted an environmental basis for the emer-
gence of the nymphal and larval stages, including such factors as microclimate of
the litter layer and humidity would make the model more realistic.
We assumed that the number of adult ticks entering and leaving our model
was equal; consequently, we made no concessions to tick migration on deer.
