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.