Biology of Sarraceniopus darlingtoniae (Histiostomatidae: Astigmata), an obligatory inhabitant of the fluid-filled pitchers of Darlingtonia californica (Sarraceniaceae)

Darlingtonia californica is a carnivorous plant with a patchy distribution in coastal Oregon and northern California, USA. A number of arthropod species inhabit and exploit its fluid-filled pitchers; among these is a hististomatid mite, Sarraceniopus darlingtonia, an obligate inhabitant that feeds on the rich microbial growth associated with decomposing arthropods captured by the pitcher. Males seek out and clasp tritonympal females, guarding them from other males by means of an enlarged second pair of legs. Upon molting, mating takes place. Eggs are laid on the pitcher wall above the fluid line, and, upon hatching, larvae move under the fluid. While larvae and protonymphs remain submerged, other instars can be found both below and above the pitcher fluid. Development from egg to adult is approximately nine days at 20oC and six days at 25oC. Mites overwinter as deutonymphs, with the first non-deutonymphal instars found in mid-March. Dispersal to newly forming pitchers on the same plant or closely adjacent plants is through ambulatory activity of deutonymphs rather than phoresy.