Download O. triseriatus

Species and developmental-dependent vulnerability to predation
among container mosquitoes
B. Alto
1,
2,
2,
B. Kesavaraju S. Juliano P. Lounibos
1 Univ. of Florida, 2 Illinois State Univ.
1
● We determined species (Ochlerotatus triseriatus, Aedes albopictus) and developmental-specific prey vulnerability to a size-limited predatory midge Corethrella appendiculata.
● Prey vulnerability was determined by measuring prey survival for combinations of the two mosquito species and developmental stages.
● O. triseriatus were larger than A. albopictus (Fig. 1).
● 2nd instars of both prey species were more vulnerable to predation than 3rd instars (Tables 1 + 3; Figs. 2 + 4 + 5).
● 2nd instar O. triseriatus suffered higher mortality when they were present with 3rd instar conspecifics relative to 2nd instar A. albopictus present with 3rd instar conspecifics
(Table 2, Fig. 4).
-Greater predation effect on O. triseriatus 2nd instars is likely due to the greater invulnerability of 3rd instar O. triseriatus, thus resulting in greater consumption of 2nd instars.
● A. albopictus 2nd and 3rd instars were relatively more vulnerable to predation compared to O. triseriatus 2nd and 3rd instars (Table 3, Fig. 5) .
● Increased size and instar of prey reduce predation.
● Species-specific differences in relative sizes may contribute to the greater vulnerability of A. albopictus to predation.
Figure 1
Table 2. MANOVA for C. appendiculata affects on survival of 2nd
and 3rd instars tested together, single prey species
Prey exposed to
predators for 24 h
Variables
df = 2, 33
Pillai’s
Trace
Species (S)
0.26 *
Predation (P)
0.84 ***
S*P
0.15
Figure 4
A. albopictus (control)
O. triseriatus (control)
A. albopictus (predation)
O. triseriatus (predation)
Table 1. ANOVA for C. appendiculata affects on survival of prey at each instar
(2nd and 3rd) and species combination tested alone
Variables
df = 1, 72
Species (S)
Predation (P)
Instar (I)
P*S
I*S
I*P
S*P*I
Figure 2
F
0.01
142.01 ***
102.09 ***
16.05 **
19.56 ***
9.79 *
0.93
Figure 3
Table 3. MANOVA for C. appendiculata affects on survival of
A. albopictus and O. triseriatus tested together at the same instar
(both 2nd or both 3rd)
Variables
df = 2, 34
Pillai’s
Trace
Instar (I)
0.75 ***
Predation (P)
0.87 ***
I*P
0.60 ***
Figure 5
2nd instar (control)
3rd instar (control)
2nd instar (predation)
3rd instar (predation)