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 addition, students are asked to consider how they could evaluate the consequences of oviposition choice by females by examining parameters such as emergence success from natal and non-natal bean species.  A shorter version of this exercise that just examines oviposition choice is also available (Natal Bean Discrimination by Bean Beetles).

Topic: Reproductive Behavior

Level: Upper-level majors

Class time: one 2-3 hour class period, plus 1 hour class period 48 hours later, 15 minutes daily for 2 weeks about 4 weeks 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 and evaluate the consequences of such choices.