Table 1.
Detour-completion latencies of Portia africana (time elapsing between beginning of trial and reaching top of Viewing Tower; Stages 1–7: see the text). Number of prey seen from Viewing Tower the same as seen from Starting Tower. Comparison of control trials (prey arrangement or prey size not changed during trial; Scene 1) with experimental trials (prey arrangement or prey size changed during trial; Scene 2). For each experiment, n for control trials is indicated. For experimental trials, n always 40. Unless otherwise stated, prey were of medium size (see the text). Adjusted alpha for Bonferroni corrections was always 0.01. All comparisons n.s.
| question | experiment | no. of prey | Scene 1 | Scene 2 | n for Control | Mann–Whitney U-test |
|---|---|---|---|---|---|---|
| Does prey arrangement matter? | 1a | 1 versus 1 | 1 prey facing right | 1 prey facing left | 60 | Z = 0.53, p = 0.594 |
| 1b | 1 prey facing left | 1 prey facing right | 20 | Z = 0.22, p = 0.829 | ||
| 2a | 2 versus 2 | 2 prey facing each other | 2 prey facing away | 60 | Z = 0.92, p = 0.356 | |
| 2b | 2 prey facing away | 2 prey facing each other | 20 | Z = 0.58, p = 0.561 | ||
| 3a | 3 versus 3 | above: 2 prey facing each other; below: 1 prey facing right | 2 prey facing right, 1 prey facing left | 60 | Z = 0.24, p = 0.807 | |
| 3b | 2 prey facing right, 1 prey facing left | above: 2 prey facing each other; below: 1 prey facing right | 40 | Z = 0.81, p = 0.419 | ||
| 4a | 4 versus 4 | 2 rows of 2 prey facing each other | 2 rows of 2 prey facing away | 60 | Z = 0.16, p = 0.876 | |
| 4b | 2 rows of 2 prey facing away | 2 rows of 2 prey facing each other | 20 | Z = 0.43, p = 0.665 | ||
| 5a | 6 versus 6 | 3 rows of 2 prey facing each other | 3 rows of 2 prey facing away | 60 | Z = 0.73, p = 0.467 | |
| 5b | 3 rows of 2 prey facing away | 3 rows of 2 prey facing each other | 20 | Z = 0.09, p = 0.925 | ||
| Does prey size matter? | 6a | 1 versus 1 | 1 small prey facing right | 1 large prey facing right | 20 | Z = 0.65, p = 0.516 |
| 6b | 1 large prey facing right | 1 small prey facing right | 20 | Z = 1.05, p = 0.291 | ||
| 7a | 2 versus 2 | 2 small prey facing each other | 2 large prey facing each other | 20 | Z = 0.08, p = 0.935 | |
| 7b | 2 large prey facing each other | 2 small prey facing each other | 20 | Z = 0.89, p = 0.372 |