Natal Bean Discrimination by Bean Beetles

Synopsis

Since larvae cannot move from the bean on which an egg was deposited, the oviposition choice of a female determines the future food resources available to their offspring. As a result, it is the most critical choice a female makes for her offspring, because it will influence their growth, survival, and future reproduction. In this experiment, students are challenged to design and perform a set of experiments to determine whether female bean beetles discriminate between their natal host and another suitable species of bean. Typical experiments include observing time spent by females on different species of beans and counting the number of eggs laid by females on natal and non-natal bean species. In an extension of this experiment (Consequences of Natal Bean Discrimination by Bean Beetles), students could evaluate the consequences of oviposition choice by females by examining parameters such as emergence success from natal and non-natal bean species.

Topic: Reproductive Behavior

Level: High School and Undergraduate Non-majors - Upper-level majors

Class Time: one 2-3 hour class period, plus 1 hour class period 48 hours later

Learning Objectives:

Design and perform a set of experiments to evaluate whether female bean beetles (Callosobruchus maculatus) discriminate between two suitable species of beans.

Christopher W. Beck¹ and Lawrence S. Blumer²

¹Department of Biology, Emory University, Atlanta, GA 30322

²Department of Biology, Morehouse College, Atlanta, GA 30314