Carnivorous bladderworts – Utricularia

Utricularia vulgaris illustration from Jakob Bladderwort illustration from Sturm's (1796) "Deutschlands Flora in Abbildungen" (image: Wikipedia)

Common freshwater plant hides a carnivorous secret

Continuing our theme of finding exceptional freshwater species in seemingly mundane and everyday habitats, the Utricularia genus of aquatic plants deploy highly sophisticated traps to catch their prey.  A remarkably hardy genus, Utricularia is found almost everywhere in the world, but it is not widely known that this pretty, seemingly harmless plant is carnivorous!

20% of the Utricularia genus are aquatic.  Aquatic species such as the common bladderwort (Utricularia vulgaris) trap invertebrates, fish fry and tadpoles with bladder traps.

Bladderwort traps (image: wikipedia)

About the size of a runner bean, the bladder traps constantly pump out water, creating a partial vacuum, “spring-loaded” in wait of suitable prey.  When a passing animal brushes the hair-like trigger levers at the entrance to the trap this vacuum-seal is broken, causing water to rush into the trap and engulf the prey.  The trap shuts within one hundredth of a second of opening, dissolving the trapped prey in digestive juices.  It’s pretty amazing what goes on unseen beneath the surface of our freshwaters!

Bladderwort stem (image: wikipedia)

Where to see:

  • Common bladderwort (U. vulgaris) is found across Europe in shallow and slow moving freshwaters.  It is identifiable by its bright yellow flowers throughout the summer months.
  • In North America, common bladderwort refers to U. macrorhiza, a different (but still carnivorous!) species.
  • A trip to your local pond or lake accompanied by a good field guide will help you find bladderwort species.

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  1. Trackback: Pea frog of Borneo – Microhyla nepenthicola « The BioFresh Cabinet of Freshwater Curiosities

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