Results
The final model for H2’ included an interaction between elevation and interaction type, and main effects of disturbance, elevation and interaction type (lmer; AICc = -34.5, n = 74, logLik = 30.3; Table 1; Figure 5a; Figure 6a). Undisturbed areas had higher network specialisation than disturbed areas (P = 0.001). Overall, myrmecophytic networks were more specialised (higher H2’ score) than other interaction types (P < 0.001). However, given the significant interaction between the effects of interaction type and elevation (P < 0.001), we interpret this result with caution. Pairwise comparisons showed that the relationship between elevation and specialisation (H2’) differed between myrmecophytic networks and both myrmecochorous and foraging networks (P < 0.001) but not with myrmecophilic networks (P = 0.130). All other pairwise comparisons were non-significant (P > 0.05). Myrmecophytic networks showed the greatest specialisation at lower elevations, with rapid decreases in specialisation with increasing elevation. Myrmecophilic networks showed a less pronounced decline in specialisation with elevation, while specialisation of myrmecochorous and foraging networks remained low at all elevations. Latitude was not included in the final model for H2’ (Figure 5e). Intriguingly, when H2’ scores were standardised by comparison with a null model (z-score), the final model included no main effects or interaction terms (lmer; AICc = 528.8, n = 74, logLik = -261.2; Table 1; Figure 5b; Figure 6b, f). That is, none of the predictors from the unstandardised H2’ model was included in the standardised model.
Accounting for phylogeny of partners, the best model for ant specialisation on plants (dsi*ants) included only network type (glmm; AICc = -70.7, n = 64, logLik = 42.1; Table 1; Figure 5c). Myrmecophytic networks were more specialised than the other three network types (P < 0.001) and myrmecophilic networks showed greater specialisation than foraging networks (P < 0.001). All other pairwise comparisons between network types were non-significant (P > 0.05). Main effects of latitude, elevation and disturbance were not present in the final model (Figure 6c, g), nor were any interaction terms. The final model for plant specialisation on ants (dsi*plants) also included only network type (glmm; AICc = -46.3, n = 64, logLik = 29.9; Table 1; Figure 4d). Myrmecophytic networks were more specialised than myrmecophilic (P < 0.001), myrmecochoric (P < 0.001) or foraging networks (P < 0.001). All other pairwise comparisons were non-significant (P > 0.05). Main effects of latitude, elevation and disturbance were not present in the final model, nor were any interaction terms (Figure 5d, h). 1.