In optimal foraging theory, the decision to forage in a particular patch depends on the balance of energy gained and what costs?

• A. Predation risk
• B. Reproductive success
• C. Habitat diversity
• D. Search and handling costs

Answer: (D)

Net energy gain is what drives foraging decisions in this framework. The key idea is not just how much energy you can collect, but how much energy you spend to get it. The main costs considered are search costs—the time and energy spent looking for food—and handling costs—the time and effort required to capture, subdue, and consume it. These costs reduce the energy you actually net from each patch, so a patch that yields a lot of energy but demands a lot of searching or handling may be less attractive than a nearby patch with easier access. If the net energy rate (energy gained minus these costs) drops below what you could obtain elsewhere, the organism should leave and move on.

While factors like predation risk can influence foraging decisions in broader models, the direct costs in the standard energy-budget view are the search and handling costs. Reproductive success or habitat variety aren’t the immediate costs subtracted from energy gained in this core calculation.