Sample collection and sorting
We collected the specimens using the standardised sampling protocol COBRA (Cardoso, 2009) in May-June 2013 and 2014 (Crespo et al., 2018; Malumbres-Olarte, Crespo, Domènech, Moya-Laraño, & Arnedo, 2020b). The sampling design included 16x1ha plots distributed in white oak forests across six National Parks of the Iberian Peninsula, namely Aigüestortes i Estany de Sant Maurici (PA), Ordesa y Monte Perdido (PO), Picos de Europa (PP), Monfragüe (PM), Cabañeros (PC) and Sierra Nevada (PS) (Fig. 1). We used semi-quantitative methods that combined 12 man-hours of timed direct capture, beating and sweeping with 48 pitfall traps active for two weeks in every plot.
We sorted adult and immature specimens and we identified them under a ZEISS Stemi 2000 stereomicroscope. We identified adults to species level and juveniles to family level. All the immature individuals of each plot were weighted separately for each family using an analytical balance. We placed the specimens in absorbent paper for 30 minutes before weighing them to allow the remaining alcohol in the bodies to evaporate.