Page 15 - Volume 6, Issue 2, July 2013
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© Benaki Phytopathological Institute
Papanikolaou
et al.
62
values from first to fourth larval instar were
6.18, 2.37, 1.06 and 0.44 h respectively.
Our study also revealed that the mean
attack rates of
P. quatuordecimpunctata
were 0.21-0.26 h
-1
and did not differ among
the larval instars. This further indicates that
the per capita prey mortality at low prey
densities did not differ among larval instars,
displaying similar ability to respond to in-
creasing prey densities. The estimated mean
values of the predator’s attack rates at 24 h
exposure time of prey were 0.06 h
-1
and did
not differ among the larval instars (Papan-
ikolaou
et al
. 2011).
Table 1.
Estimated parameters of the logistic regression analysis of the proportion of
Aphis
fabae
prey eaten by the larval instars of
Propylea quatuordecimpunctata
, as a function of ini-
tial prey density.
Parameter
1
st
instar
2
nd
instar
3
rd
instar
4
th
instar
P
0
-1.03 ± 0.14
0.48 ± 0.12
-0.24 ± 0.08
0.91 ± 0.11
P
1
-6.88 ± 0.89
-9.79 ± 0.77
-8.96 ± 0.53
-9.27 ± 0.66
P
2
2.79 ± 0.91
4.56 ± 0.77
3.26 ± 0.51
2.37 ± 0.62
P
3
-1.19 ± 0.94
-2.25 ± 0.74
-1.16 ± 0.48
0.86 ± 0.55
Figure 1.
Observed
vs
fitted probabilities of
Aphis fabae
prey
eaten by the larval instars of
Propylea quatuordecimpuncta-
ta.
L1: first instar larvae, L2: second instar larvae, L3: third instar larvae and L4: fourth instar larvae.
