Variation in network metrics
In agreement with our first hypothesis, we found that the generality of
the observed networks decreased with increasing temperature (observed
slope = -0.4973, P = 0.035; Fig. 2, Table 1) which was consistent
with a decrease of the overall network specialization (H2’) along the
elevation (Appendix S1, Fig. S4a, Table S1). The variation in these
metrics differed significantly from null models, as we found their
observed slopes to be outside the 2.5–97.5% quantile interval of the
slopes obtained from random networks and SES values were high
(generality: 2.5–97.5% quantile interval = (-0.4066, -0.1868), SES =
-3.44; overall network specialization in Table S1). We further found a
negative relationship between the weighted nestedness and the
temperature for empirical webs that was different from null models
(observed slope = -0.0102, P = 0.042, 2.5–97.5% quantile
interval = (-0.0054, -0.0060), SES = -3.51; Fig. 2, Table S). We found a
positive relationship between robustness and temperature (slope =
0.0033, P = 0.023), but the observed decrease in robustness in
cold environments was lower than expected from nulls models (2.5–97.5%
quantile interval = (0.0057, 0.0082), SES = -5.77), indicating a role of
the wiring of interactions in attenuating the decrease in robustness
toward colder conditions (Fig. 2). Variation in the number of links per
species (Fig. 2, Table 1), the connectance and the trophic niche overlap
of orthoptera (Appendix S1, Fig. S4b and S4c, Table S1) were not
different between the observed and the randomized networks. We found a
positive relationship between temperature and the number of links per
species in empirical networks (Fig. 2a, Table 1) but not for the
connectance or the niche overlap (Appendix S1, Fig. S4b and S4c, Table
S1).