Fruiting bodies created by social amoebae increase spore dispersal by arthropods. (A) Dispersal assay. Amoebae created fruiting bodies on agar in the bottom of a conical tube. We disrupted fruiting bodies in some tubes by banging them several times against a hard surface, dislodging spore masses and causing fruiting bodies to fall over. We then turned tubes sideways and introduced fruit flies. At various times we sampled tubes and counted spores recovered from washed flies. (B) Flies pick up spores more readily from intact fruiting bodies. Data show mean ± SEM of 3–4 independent experimental replicates.