Fig 1.
Arena was divided intro into three circular parts by two circles of respectively 5 cm and 16 cm diameter: i) the central zone, ii) the inter-zone and iii) the border zone. Ten T. officinale seeds were placed around each circle. This representation is approximately to scale: carabids measure ~1 cm and seed ~2.5 mm in length.
Fig 2.
Schematic diagram of the chronological course of the experiment and the temporal metrics use in the tests.
Latency to first movement was measured from the release of the test carabid to its first movement greater than its average body length; the latency to first acceptance of a seed was measured as the time from the first movement of an individual until it accepted the first seed; handling time is the duration of the seed consumption starting from an individual seizing the seed in its mandibles until it released the empty tegument. The experiment ended after a duration of 3600 s.
Table 1.
Contrast analysis between treatments for the latency to first movement.
Fig 3.
Kaplan-Meier plot for the latency to first acceptance as a function of the treatments.
Each curve represents, for a given treatment level, the proportion of individuals with no consumption as a function of the time since the first move: control (continuous line, n = 70), intraspecific competition (grey line, n = 71), interspecific competition (dotted line, n = 75) and predation (bold line, n = 74). Individuals not eating before the end of the observation at time t = 3600 s were treated as censored data in the model.
Table 2.
Contrast analysis between treatments for the latency to first acceptance of a seed.
Fig 4.
Mean number (bootstrapped +/- 95%CI) of seeds eaten per individuals after one hour of test in each treatment.
Different letters correspond to statistically significant difference between treatments (post-hoc pairwise comparison with Tukey adjustment for multiple comparisons). The sample sizes are shown above the x-axis.
Fig 5.
Proportion of space used (bootstrapped +/- 95%CI) after one hour of test in each treatment.
Different letters correspond to statistically significant differences between treatments (post-hoc pairwise comparison with Tukey adjustment for multiple comparisons). The sample sizes are shown above the x-axis.