ANT_lab_2018_166.doc - BioSci 166 Page 1 of 4 FORAGING...

This preview shows page 1 - 2 out of 4 pages.

BioSci 166 Page 1 of 4 FORAGING BEHAVIOR AND ECOLOGY IN DESERT SEED-EATING ANTS This weekend we will do a project examining the foraging ecology of harvester ants in the desert. This handout provides some background on the project and then describes the procedures we will be using. The project takes an experimental approach to the study of behavioral ecology and will include both lab and field work. It is designed around our weekend field trip to Anza Borrego State Park. We will stay at a UC reserve within the Park. GENERAL BACKGROUND I. Introduction to Optimal Foraging Theory Diet choice by animals plays a central role in ecology and has been the subject of investigation from many perspectives including foraging theory, coevolution, and community structure. One prominent approach, foraging theory, analyzes the diet choices that are favored by natural selection. Usually this is done by assuming that selection maximizes net rate of energy intake (Pyke et al. 1977). The idea is that selection will favor individuals who make foraging choices that yield the highest net rate of energy gain, subject to constraints that put limits on the animal's ability to feed in a certain way. Such constraints may result from the animal's morphology and physiology or may be placed on the animal by the environment in which it lives. To see how these ideas can be applied, note first of all that simple foraging models predict that prey types will be added to the diet in order of their profitability. Thus, assuming that consumers have perfect knowledge and forage optimally, you can predict their diet if you know three things: energy content of the food ( E ), handling time ( h, the time it takes a consumer to pursue, subdue, consume its prey), and search time ( s , the time it takes a predator to find its food). Prey Profitability is defined as the ratio of net energy gained from a prey item to the time spent obtaining the prey item, or E/h . Theory predicts a forager should maximize its rate of net energy intake, related to E, h and s as follows: Rate of net energy intake = E/(h+s) If we ignore search time (or control for it as we do in this lab), the problem for a forager is this: If it only pursues high E foods it may take a lot of time collecting prey items with high h . If it pursues low h it may collect mostly low E foods. E and h may in turn trade off (may be negatively correlated), i.e. energetically rich foods may be difficult to handle, and easy to handle foods may be energetically poor. So a forager needs to solve this optimization problem in order to maximize energy intake (E).
Image of page 1
Image of page 2

You've reached the end of your free preview.

Want to read all 4 pages?

  • Fall '19
  • Optimal foraging theory

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern

Stuck? We have tutors online 24/7 who can help you get unstuck.
A+ icon
Ask Expert Tutors You can ask You can ask You can ask (will expire )
Answers in as fast as 15 minutes