SPITTLEBUG INDICATORS OF NITROGEN-FIXING PLANTS

1. Spittlebugs (Homoptera: Ceropoidea) are preferentially associated with nitrogen-fixing angiosperms. Generally, the Aphrophoridae associate with legumes, the Clastopteridae with actinorhizal plants, and the Cercopidae with associative nitrogen-fixing grasses. This is the first reported insect-host association specific to nitrogen-fixing plants. 2. It is probable that spittlebugs are attracted to nitrogen-fixing plants because these hosts provide a relatively rich, reliable source of organic nitrogen compounds for xylem-sucking insects. 3. Many spittlebugs live on plants that do not fix nitrogen, and ecological, mechanical or chemical factors may bar some spittlebugs from otherwise suitable nitrogen-fixing plants. 4. Among nitrogen-fixing hosts, spittlebugs appear to prefer plants that transport fixed nitrogen as amino acids and amides to plants that transport fixed nitrogen as ureides.