Figure 1
Location of oak trees included in the study. An interactive version of this map can be found in the Supplemental File as Figure 1.
Figure 2
Precision and accuracy of school children (a) and professional scientists (b) in assessing attack rate (% artificial larvae with predation marks). Dots represent attack rate aggregated at the level of oak trees for each survey separately. Dot size is proportional to the number of overlapping dots. Dashed lines indicate a 1:1 relation. In Panel a, the thick dashed red line represents the non-significant regression line (y = 0.08·x + 50.32, marginal R2: Rm2 < 0.01, conditional R2: Rc2 = 0.66). In Panel b, the bold red line represents the significant regression line (y = 0.66·x + 23.41, Rm2 = 0.31, Rc2 = 0.78). EVC, Elena Valdés Correcher (a single professional scientist trained to identify predation marks on artificial larvae).
Figure 3
Comparisons between insect herbivory as estimated by school children, trained scientists, and untrained professional scientists. Empty dots represent individual observations (i.e., a single assessment on a particular leaf set). Filled circles and vertical bars represent means ± SE of the raw data.
Figure 4
Examples of real and false-positive observations of predation. (a) Grey arrows point to typical bird predation marks. The black arrow points toward marks made by the wire when attaching the caterpillar on the branch and taking it off. (b) White and grey arrows indicate marks made by arthropod mandibles and bird beaks, respectively. (c) Black arrows indicate typical marks erroneously counted as predation marks by school children. The scar-like mark on the top caterpillar was made when rolling the caterpillar onto the wire. Deep marks on the bottom caterpillar are imprints of branches and buds.