Arthropod associates and macronutrient status of the red-ink sundew (Drosera erythrorhiza Lindl.)

Arthropods found associated with field populations of the Western Australian red‐ink sundew, Drosera erythrorhiza, were evaluated for their trophic relationship to the plant in a bushland site of the Spearwood Dunes System near Perth. The major prey of Drosera leaves was the collembolan, Hypogastrura vernalis, whose presence in the Perth metropolitan area is a new record for Australia. Additional arthropods found associated with Drosera included primary consumers and opportunistic predators that scavenge captured prey items. Physical models of Drosera leaves were placed in the field and used to estimate potential leaf capture rate immediately prior to Drosera senescence. These data were coupled with nitrogen (N), phosphorus (P), and potassium (K) analysis of soil, Drosera components and insect prey to determine that H. vernalis populations in the study area were sufficient to supply 100% of the observed sundew N and P pool, but a negligible proportion of the K pool. Soil sources of K exceeded any potential contribution of insect K.