Fig. 5. Mean sound pressure levels of the echoes (significance levels are given in Table 2). (A) In the air, the sound pressure level (SPL) in the 2 ms time window of the expected echo (enclosed by vertical dotted lines) was significantly higher in the presence of a mealworm (red) than in its absence (black). (B) On the linoleum screen, the SPL in the same 2 ms time window was significantly higher in the presence (red) than in the absence (black) of the mealworm. (C) On the clutter screen, the SPL in the presence of the mealworm (red) did not differ significantly from that in the absence of the mealworm (black). (D) A, B and C (with mealworm) plotted on one graph for comparison. The SPL reflected by the mealworm on the linoleum screen (red) is higher than that reflected by the mealworm in air (grey). Clutter screen: black.