Supporting data for "Urban landscape composition, building morphology and the heat island effect influence cavity nesting insect diversity through their effects on local herbaceous plant communities."

Trap nest occupancy data collected from 58 standardized trap nests installed throughout the metropolitan area of Strasbourg (France) during 2022. Trap nests consisted of a rectangular wooden (Aucoumea klaineana) container measuring 20 cm depth by 8 cm width and height. The container was filled with two cut logs (Prunus, Quercus and Salix spp.) with drilled holes (one of 10 mm diameter, two of 6 mm and four of 4 mm), cut stems of bamboo (Phyllostachys spp.: one stem of 2 to 3 cm in diameter, three stems of 1 to 1.5 cm in diameter, five stems of 0.8 to 1.2 cm in diameter, 10 stems of 0.4 to 0.7 cm in diameter; Pseudosasa japonica: One handful of 5 cm diameter of stems each less than 0.4 cm diameter) and cut stems (< 0.5 cm diameter) of reed (Phragmites australis) to fill the gaps. All traps were installed at the onset of spring, in the period spanning 06/04/2022 to 13/04/2022. They were placed on broad-leafed tree trunks, facing south, at 3 m height to avoid vandalism. This setting enabled us to study their community-level responses in standardized conditions.All trap nests were assessed three times in the seasons following their installation: spring (01/06/2022 to 10/06/2022), summer (22/08/2022 to 24/08/2022) and winter (30/11/2022 to 02/12/2022) spanning a period of 6 months between the first and the last visits. During each assessment, we noted the number of nest plugs present as a proxy to cavity-nesting insect abundance. Nest plugs were classified according to their composing material into the following categories (see material-taxon associations table): mud, cotton, membrane, pebbles, leaf pulp, resin, wood pulp, grass, leaf cuts and loose debris.