Lecture F1 (2024-10-24): Foraging Foundations

In this lecture, we introduce the foundations and key motivations behind the study of foraging behavior, including some of the foundations of (optimal) foraging theory. We start by highlighting how the key difference between plants and animals comes down to energy acquisition and movement and thereby establish foraging (the search for food) as a key driver of movement behavior in "animated" animals (as opposed to "planted" plants that do not have to search for their source of energy but do have to compete for access to it). We note that movement is also needed for other contributors to reproductive success, such as fighting, fleeing, and reproduction, and so foraging strategies must balance the direct gains of those strategies against the opportunity costs of other things that could be done with that time. Toward that end, we introduce fitness proxies and give a rationale for why energetic rate of gain is a common proxy used that encapsulates the opportunity cost of other activities. We then discuss motivational examples from the study of quail foraging behavior and nutrient-constrained foraging in sloths.

Topic highlights:

• movement and its role in energy acquisition as the key discriminator between plants and animals
• foraging as one of the major drivers of movement behavior
• opportunity costs while foraging, both in terms of non-foraging activities and alternative foraging activities
• fitness proxies and the rationale for the use of energetic rate maximization (as opposed to absolute energetic maximization)
• functional response curves and Holling's disc equation
• motivational examples:
  • simultaneous choice of diet and prey search speed in quail
  • sloth–moth–fungus–algae mutualism and its role in shaping nutrient-constrained sloth behavior

Important terms: autotroph (primary producer), heterotroph (consumer), foraging, opportunity cost, fitness proxy/fitness surrogate/currency, functional response (type-I, type-II, type-III), Holling’s disc equation, handling time, instantaneous rate of capture of each prey