Data from: High specialization and limited structural change in plant-herbivore networks along a successional chronosequence in tropical montane forest

Secondary succession is well‐understood, to the point of being
predictable for plant communities, but the successional changes in
plant‐herbivore interactions remains poorly explored. This is
particularly true for tropical forests, despite the increasing
importance of early successional stages in tropical landscapes.
Deriving expectations from successional theory, we examine properties
of plant‐herbivore interaction networks while accounting for host
phylogenetic structure along a succession chronosequence in montane
rainforest in Papua New Guinea. We present one of the most
comprehensive successional investigations of interaction networks,
equating to more than 40 person years of field sampling, and one of
the few focused on montane tropical forests. We use a series of nine
0.2ha forest plots across young secondary, mature secondary and
primary montane forest, sampled almost completely for woody plants and
larval leaf chewers (Lepidoptera), using forest felling. These
networks comprised of 12,357 plant‐herbivore interactions and were
analysed using quantitative network metrics, a phylogenetically
controlled host‐use index and a qualitative network beta diversity
measure. Network structural changes were low and specialisation
metrics surprisingly similar throughout succession, despite high
network beta diversity. Herbivore abundance was greatest in the
earliest stages, and hosts here had more species‐rich herbivore
assemblages, presumably reflecting higher palatability due to lower
defensive investment. All herbivore communities were highly
specialised, using a phylogenetically narrow set of hosts, while host
phylogenetic diversity itself decreased throughout the chronosequence.
Relatively high phylogenetic diversity, and thus high diversity of
plant defenses, in early succession forest may result in herbivores
feeding on fewer hosts than expected. Successional theory, derived
primarily from temperate systems, is limited in predicting tropical
host‐herbivore interactions. All succession stages harbour diverse and
unique interaction networks, which together with largely similar
network structures and consistent host use patterns, suggests general
rules of assembly may apply to these systems.