Rapid turnover of traps in Utricularia vulgaris L.

Utricularia vulgaris growing at Wicken Fen, England, showed rapid turnover of the trapping apparatus. New groups of leaves, each bearing many traps, were produced at a rate of 1.4-2.8 groups per day from April to September, 1987. Old leaves decayed at a comparable rate, so that individual leaves survived for less than 50 days. In July, trapping efficiency of individual bladders was greatest between 1 and 6 days of age and then declined rapidly. Very few traps more than 19 days old could capture prey and most were lost from the leaves within 32 days. The lifespan of traps was closely related to their size and position on the leaves. Because of the rapidity of changes in trap condition with age, trap age is a vital consideration in any studies of the functional ecology of U. vulgaris.