CAPTURE RATES OF INVERTEBRATE PREY BY THE PITCHER PLANT, SARRACENIA-PURPUREA L

I examined capture rates of invertebrate prey by pitchers of the purpl e pitcher plant Sarracenia purpurea,in western Newfoundland, Canada. W hile captures were diverse, Hymenoptera (mostly ants), Coleoptera and Gastropoda accounted for 69% of the total dry mass caught. Gastropoda decompose quickly and completely in pitchers, and their importance (20 %) implies that prey sampling methods that do not survey freshly caugh t prey may seriously underestimate resource availability in pitchers. The average pitcher caught 11 mg dry mass of animal biomass over its l ifetime, but capture rates were highly variable (range 0-67 mg). Pitch ers opening earlier in the season caught no more or less than those op ening late. Larger pitchers caught more than smaller ones, although si ze accounted for a small fraction of total variance. Capture rates cha nged with time, peaking in pitchers 12-33 days old; however, pitchers continued to catch prey through their 2nd season (i.e., after overwint ering). In an average pitcher, 2nd-season captures made up nearly half of the total.