Phosphorus Contents in Desert Riparian Spiders and Insects Vary among Taxa and Between Flight Capabilities

Abstract

ABSTRACT Phosphorus occurs in a variety of biological molecules including DNA and RNA, ATP and other adenine nucleotides, phosphorylated metabolites, and phospholipids. Variation in phosphorus content among spiders and insects would influence the element's uptake by insectivorous birds. I measured amounts of phosphorus in 3 families of spiders and 7 orders and 24 families of insects collected in riparian habitat next to the Colorado River in western Arizona. Relation between phosphorus mass and body dry-mass, P µg = 9.6 (body mg), in spiders and insects was not allometric. Phosphorus concentration, as a mean percentage of body dry-mass, was higher in spiders (1.33%) than in insects (0.96%). Phosphorus contents varied most among families but also among orders and genera. Insect predators contained higher phosphorus concentrations (1.01%) than insect herbivores (0.90%). Strongflying insects, Odonata, Neuroptera, Diptera, and Hymenoptera except Formicidae, also contained higher phosphorus concentrations (1.0...