Understanding spatiotemporal trends on insect-plant interaction networks is essential to unveil the ecological and evolutionary processes driving herbivore specialisation. However, community studies accounting for temporal dynamics in host-plant specialisation of herbivorous insects are surprisingly scarce.

Here, we provide the background data which were used to investigate how seasonality affects specialisation of a temperate forest herbivore community.  This dataset results from a comprehensive sampling of more than 4,700 folivorous caterpillars associated with 16 deciduous tree species in eastern North America. Specifically, we provide three abundance-based plant-caterpillar interaction matrices. Each interaction matrix represents a six-week period of the growing season. These time periods are defined as follow: early season, midseason, and late season.

We observed a significantly less specialised herbivore fauna in the early season than in the two subsequent summer seasons. We further found that the seasonal increase in specialisation was driven by a remarkable turnover in species composition rather than by shifts in guild structure or intraspecific changes in diet breadth of the herbivores.

Location: Toms Brook (Virginia, USA; 38°55’ N, 78°25’ W; 220 m a.sl.)

Folivorous caterpillars (miners excluded) were collected from all deciduous tree individuals ( ≥ 5 cm DBH) within two 0.1 ha plots.

Total: 184 tree indiviuals in 16 species; 4710 caterpillars in 243 species.

The sampling was carried out in two consecutive years - between April, 2016 and August, 2017.

Seasons: early season (26 Apr.-6 June), midseason (7 June-18 July), late season (19 July-29 Aug.)

Species identification was based on caterpillar morphology, aided by comprehensive DNA barcoding

Quercus rubra agg. comprises tree individuals of Quercus rubra L., Quercus velutina Lam., as well as their hybrids.