Excess digestive capacity in predators reflects a life of feast and famine.

摘要: In an ideal world, food supplies would be regular and frequent, so organisms could invest in just the right amount of capacity for digestion (which comes at a cost). But faced with unpredictable supplies, must spare digestive capacity, that when is available they can process it. Jonathan Armstrong Daniel Schindler have modelled dynamics supply investment digestion, collected data on actual capacities 38 fish species. They find maintain up to three times more than need. The excess suggests predator–prey encounters are much patchier generally assumed. A central challenge predators achieving positive energy balance prey spatially temporally heterogeneous. Ecological heterogeneity produces evolutionary trade-offs physiological design predators; this because ability capitalize pulses abundance requires high food-processing, yet maintaining such imposes energetic costs taxing during periods scarcity1,2. Recent advances physiology show variation foraging opportunities predictable, animals may adjust by rapidly modulating their system track opportunities1. However, it increasingly recognized unpredictable3, which should favour food-processing exceeds average levels consumption (loads)2,4. Despite basic principle quantitative design, estimates load:capacity ratios wild virtually non-existent1. Here we provide extensive assessment systems wild, compiling 639 across species fish. We found piscine typically feed daily rates 2–3 higher what experience average. numerical simulation trade-off between metabolic cost observed level opportunism profitable only if encounters, thus predator budgets, far variable nature currently