Research Article

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

Table 1

Best model structure and main parameter estimates relative to enemy biodiversity effects on whitefly nymph survival.

CodeModel structureModel selection diagnosticsMaximum likelihood estimates of model parameters
ΔQAICc

S1 ; all 57.62530.0000272.36751.00000.00000.07290.30040.00000.00000.49140.16110.02560.11920.2908
S2 34.45100.0000212.22860.99440.00050.08690.28600.41840.24740.48990.10970.15410.17870.1552
S3 14.27990.0004151.86870.98100.00150.08940.31280.39050.28700.50290.11630.16330.18020.1700
S4 11.54750.0014141.82250.97870.00170.09140.30010.37980.26150.47840.11480.16140.17850.1678
S5 26.32800.0000131.69590.90720.00750.09060.10210.16450.08500.13040.13360.20370.23060.1646
S6 24.18240.0000131.49220.88720.00920.27160.25910.22000.37590.12080.15980.18780.1662
S7 8.33660.0070131.78400.97830.00180.09140.3019= 0.26160.47880.11590.16330.18040.1739
S8 5.31570.0317121.75650.97850.00170.09170.2976= = 0.50060.11620.16380.18090.1757
S9 5.12250.0350111.77950.97590.00200.09170.3323= = = 0.11520.16190.17920.1704
S10 8.11800.0078111.61090.95150.00390.09310.2973= = 0.50010.1189= 0.15880.1520
S11 10.51810.0024111.65210.94780.00420.10060.3013= = 0.52030.13070.1590 = 0.1711
S12 9.21090.0045111.56670.94610.00440.09270.2874= = 0.43880.12380.14940.1684=
S13 0.02440.4473101.70540.97800.00180.09280.2974= = 0.49720.11800.1750= =
S14 ; 0.00000.452891.72920.97550.00200.09290.3338= = = 0.11710.1722= =
S15 7.69050.009781.53020.92240.00630.09810.3221= = = 0.1244 = = =
S16 25.70160.000081.48430.00000.01510.08990.3239= = = 0.08520.1631= =
S17 57.86750.000031.14550.00000.08130.2412



The general model S1, all, specifies that: there is a constant unknown mortality of whitefly nymphs in all replicates ( ); predation rates on whitefly nymphs varies with predator identity ( ), blocks ( indicating that varies with predator identity) and whitefly nymph 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: S1 → S2: no predation from O. lineatus is assumed (all →  ); S2 → S3: no predation from P. phrygianus is further assumed ( ); S3 → S4: block effect constant between predator species (  → B); S4 → S5: effect of starting whitefly density on predation rates constant between predators ( ); S4 → S6: unknown mortality absent (  →  ); S4 → S7: per capita predation rates of M. melanotoma are identical in Mm and Mm + Nt treatments ( ), and so on (S7 → S8 → S9; S8 → S10; S8 → S11; S8 → S12; S8 → S13 → S14 → S15; S14 → S16). : 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 are: unknown mortality ( ) and per capita predation rates of predators in single-(e.g., for M. melanotoma) and multiple-predator treatments (e.g., for M. melanotoma when in combination with N. tenuis). The sign — indicates that the parameter has been set to zero. Best models in bold.