Dictyostelium fruiting bodies primarily consist of:
Mature sorocarps consist of two cell types with opposite fates. Prestalk cells, after depositing cellulose tube, swell vacuoles, synthesize thick walls, and die, forming rigid stalk that supports sorus above substratum. Dead stalk provides mechanical strength and prevents desiccation without competing for germination resources. Spores remain alive, encapsulated, dehydrated, containing trehalose and heat-shock proteins for longevity. Structure composed of live stalk plus spores would collapse and consume nutrients. Therefore stalk sacrifice representing altruism illustrates kin selection where
Ref: Principles of Development, Lewis Wolpert, Chapter 3: Dictyostelium fruiting body - altruistic stalk cell death.