Describes three experiments for undergraduates which illustrate associations of parasites with their host. Includes a table of parasite-induced alterations of selected host species. Instructional suggestions are also provided. (ML)

Background information on the biology of aphids is supplied. Using this information in a wide variety of investigations, many involving equipment and techniques available in the school laboratory, can be carried out. An appendix lists possible projects. (Author)

Activities that consider the courtship behavior and mating patterns of millipedes are presented. The functional significance of a behavior that has evolved through indirect competition between males is discussed. The procedures for seven experiments, results, and interpretations are included. (KR)

An activity simulating natural selection in which wild birds are predators, green and brown pastry "baits" are prey, and trays containing colored stones as the backgrounds is presented. Two different methods of measuring selection are used to describe the results. The materials and methods, results, and discussion are included. (KR)