It is becoming clear that many kinds of animals can distinguish between relatives and unrelated individuals. Studies of kin recognition have emphasized how the behavior develops and the sensory mechanisms used in recognition (i.e., visual, auditory, chemical cues). Although two basic functions of kin-recognition behavior (inbreeding avoidance and ensuring that aid-giving behavior is directed toward relatives) are recognized, empirical evidence as to the significance of kin-recognition behavior is lacking. This is especially true for amphibian larvae, which have been the subjects of extensive research on kin recognition. Amphibian larvae are ideal subjects for studying kin-recognition behavior because the behavior is easy to observe and to quantify, experimental manipulation is possible, and detailed accounts of the natural history of the species are available. Previous research on kin recognition in amphibian larvae has provided important information on the roles of learning and heredity in the development of the behavior. Furthermore, past research has revealed that different species have different abilities to recognize kin. Dr. Blaustein's research is designed to test hypotheses about the adaptive value of kin-recognition behavior. This aspect of the kin-recognition phenomenon is the least understood. Both theory and empirical evidence suggest that growth and development may be influenced by the composition of the social group. Past research has shown that growth and development of insects and mammals are influenced by the genetic composition of the animals within a group. Therefore, Dr. Blaustein will test the influence of the genetic group composition on growth and development in Cascades frog tadpoles. This species has the most sensitive kin- recognition system of any amphibian. Dr. Blaustein predicts that tadpoles living in groups composed primarily of kin will grow and develop faster than those in groups composed of kin and non-kin. This portion of the investigation should greatly enhance our knowledge of the kin-recognition phenomenon in general. Observations in nature and laboratory experiments illustrate that predation is one important selective force in the formation of animal groups. This seems to be especially true for tadpoles. Therefore, Dr. Blaustein will conduct experiments dealing with the relationship between group formation and kin-recognition. He predicts that tadpoles will form groups composed primarily of kin because when they release a chemical alarm substance, the animals that are warned are nearby relatives.
