Research Article

Evaluating the Structure of Enemy Biodiversity Effects on Prey Informs Pest Management

Table 2

Best model structure and main parameter estimates relative to enemy biodiversity effects on whitefly nymph survival, adult emergence and survival (joint analysis).

CodeModel structureModel selection diagnosticsMaximum likelihood estimates of model parameters
ΔQAICc

J1 (S13)    all 64.67970.000391.53510.11660.20770.44660.22720.27200.00000.17500.00000.51980.00000.00000.0000
J2 (S13)   all 61.57430.000381.52550.11660.20770.44660.22720.27200.00000.17500.00000.51980.00000.00000.0000
J3 (S13)    all 38.16120.000301.45280.11660.20770.44730.22690.27250.00000.17510.00000.27450.01520.00000.0000
J4 (S13)  27.23390.000261.41900.11660.20770.44730.22690.27250.00000.09620.00000.27450.08150.08730.0000
J5 (S13)  16.80630.000221.38670.11660.20770.44730.22690.27250.00000.09180.00000.27450.08150.09180.0000
J6 (S13)  5.63300.016161.34400.01090.23260.43100.22340.0000= = = 0.0498= = =
J7 (S13)  3.26480.051151.33670.01090.23260.43100.22340.0498= = =
J8 (S13) 0.39070.216151.33500.08860.21430.44110.22490.2642=
J9 (S13) 0.00000.263151.33510.10370.21080.44430.22660.2395= =
J10 (S13) ; 1.01720.158151.33620.07340.21790.43940.22580.1484= = =
J11 (S13) 1.07710.153141.32970.00000.23520.42750.2223
J12 (S14)  1.23220.142141.34550.10600.21020.44410.22640.2389= =
J13 (S13)  3.41940.045151.33700.00000.23520.42750.2223
J14 (S13)  45.77000.000141.30630.39110.3344= 0.2036= =


ML estimates of parameters relative to predation on nymphs for Model J9

−0.08920.09350.00190.00150.00760.2563= = 0.42860.11370.1686= =

The general model J1, (S13)    all, specifies that: model structure for whitefly nymph survival is as in S13, (S13); emergence rates vary with blocks, ; relatively to whitefly adult survival, , there is a constant unknown mortality in all replicates ; predation varies with predator identity , blocks ( indicating that varies with predator identity) and whitefly density ( indicating that varies with predator identity); species-specific predation rates vary also between single- and multiple-predator treatment ; parameter structure refers to all four predators, (all). The variation of model structure following each simplification step is: J1 → J2: unknown mortality absent (  →  ); J2 → J3: block and starting whitefly density effects absent (  →  ); J3 → J4: no predation from N. tenuis is assumed (all →  ); J4 → J5: no predation from M. melanotoma is further assumed ( ), and so on (J5 → J6; J5 → J7; J5 → J8; J5 → J9; J5 → J10; J9 → J12; J9 → J13). : number of model parameters (including the dispersion parameter of the negative binomial distribution, , and overdispersion, ). Model selection diagnostics are described in the method section. Parameter estimates presented are: emergence rates for block A and B ( and ) and per capita predation rates of spiders in single- (e.g., for O. lineatus) and multiple-predator treatments (e.g., for O. lineatus when in combination with P. phrygianus). At the bottom of the table is also presented the full set of parameter estimates from model J9 relative to predation on whitefly nymphs. The sign — indicates that the parameter has been set to zero. Best models in bold.