What reduces profitability of a prey item?
Prey profitability is commonly measured as energetic value E divided by handling time h. A long handling interval lowers E/h because the predator spends more time capturing, subduing, opening, or consuming the same energy package. High energy raises profitability, while rapid capture tends to shorten handling and increase it. Search time affects the habitat-wide rate of intake and whether lower-ranked prey should be accepted, but it is not part of the basic post-encounter profitability ratio. Natural defenses such as shells, spines, toxins requiring careful processing, or difficult body size c
Ref: Ecology: From Individuals to Ecosystems, Begon et al., 5th Ed., Ch. 10