Stomach fullness shapes prey choice decisions in crab plovers (Dromas ardeola)
Fig 2
(a) AFDM (ei) plotted versus crab width (mm) (note the logarithmic axes). Grey triangles represent Macrophthalmus and blue dots represents Portunus. Non-filled rhombs represent the amount of AFDM (ei) that was left in depredated carapaxes of Portunus. The amount left in the carapaxes in terms of AFDM (ei) was subtracted from the AFDM (ei) of intact Portunus, yielding the amount of AFDM (ei) obtained by crab plovers, superimposed with a red line. For formulas see Table 1. (b) Handling time (hi) plotted versus crab width (mm) (note the logarithmic axes). Handling time does not increase significantly with size for Macrophthalmus (superimposed with a grey line), while for Portunus handling time significantly increases with size (superimposed with a blue line). For formulas see Table 1. (c) Profitability (AFDM (ei) / handling time (hi)) plotted versus crab width (mm) (note the logarithmic axes). Grey triangles represent Macrophthalmus and blue dots represent Portunus. Profitability significantly increases with size for Macrophthalmus (y = 0.22x1.85; superimposed with a grey line), while for Portunus profitability does not significantly increase with size (y = 5.46x0.03; superimposed with a blue line).