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.
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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. |