„ Populační ekologie živočichů "
Stano Pekár
Effect of conditions
► all conditions affect population growth via controlling metabolic processes in ectotherms
► temperature, humidity, day length, pH, etc.
Lepidoglyphus sp.
Rate
Universal effect of temperature
► temperature affects population growth of ectotherms
■ rate of metabolism increases approx. by 2.5x for every 10 °C
0io = 2-5
► physiological time - combination of time and temperature
► universal temperature dependence:
- rate of metabolism B:   B ~ e
- rate increases with body mass (M):
- biological time tb:
1/ -A
0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0
10
A A. siro ■ C. malaccensis
t~M/4e /T
15 20
Temperature [°C]
25
30
Linear model
► model is based on the assumption that developmental rate is a linear function of temperature T
► valid for the region of moderate temperatures (15-25°)
► at low temperatures organisms die due to coldness
D .. development time (days) v .. rate of development = 1/D Tmin .. lower temperature limit - temperature at which
developmental rate = 0
0.045
ro
+■>
c E
Q.
O
> Q
0.04 0.035
0.03 0.025
0.02 0.015
0.01 0.005 0 -I
0
♦
5
10       15       20       25       30 35
Temperature
ET.. effective temperature .. developmental temperature between T and Tmin S .. sum of effective temperature .. number of degree-days [°D] required to complete development
.. does not depend on temperature = D*ET
Tmin and S can be estimated from the regression line of v = a + bT
T '
mm '
a + bT = 0
T =-£
min 7
b
S:
S = D(T-T   ) = D
mm /
T + -b
► sum of effective temperature (S) [°D] is equal to area under temperature curve restricted to the interval between current temperature (T) and Tmin
► biofix .. the date when degree-days begin to be accumulated
time, days
i=\
► when development rate is a non-linear function of temperature
► ET.. developmental temperature between Tmin and T
max
► at high temperatures organisms die due to overheating
Tmax .. upper temperature threshold - temperature at which developmental rate = 0
0)
>_ c
E
Q.
_o
> Q
0 10 20 30 40
Temperature
|Vl3;
mm
time, days
► several different non-linear models (Briere, Lactin, etc.)
► allow to estimate Tmin, Tmax and Topt (optimum temperature)
► easy to interpret for experiments with constant temperature
► instead of using average day temperature, use actual temperature
Briere et al. (1999)
v = a x T x (T - Tmin ) x JTW - T
v .. rate of development (=11 D) T.. experimental temperature Tmin.. low temperature threshold Tmax.. upper temperature threshold a .. unknown parameter
Optimum temperature:
0 Tmin
j     Topt Tmax
A T _|_ _i_     /l     rT 2       .   qti 2 i     >yf /y-f
. _ max min       \ max min min max
► parameters are estimated using non-linear regression
Lactin et al. (1995)
v .. rate of development
T.. experimental temperature
rm, A, p, <f>.. unknown parameters
0 Tmin
rmaY and T • can be estimated from the formula:
IllaA II11I1
0 = epT - e(pTm~T"^T) + </)
Tnn* can be estimated from the first derivative:
opt
-= pe'--e
3r A
T —T 1    pTm m