Which
insects do butterworts catch?
Generally
the passive trapping mechanisms of butterworts are only able to catch
small insects. Larger and stronger prey, like ants or aphids, can free
themselves from the sticky mucilage. Smaller insects, like whiteflies
or 'mushroom' flies, are the preferred prey. But sometimes even big
insects with large wings are not able to escape when a large part of
the wings get in contact with the deadly mucilage.
The
enzymes, secreted by the sessile glands, transform chemically the prey
into nutrients, essential for the plant growth, especially nitrogenous
and phosphate containing compounds. The non-digestible parts of the
prey remain on the surface of the leaves and come back into the
nutrient cycle together with the old, decaying leaves of the
butterworts.
Some
butterwort species are even able to move their leaves when an insect is
caught. Triggered by the prey's movements, the leaf margin curls up,
forming a bowl. On one hand this movement enlarges the surface that
glands can act on digesting the insect. On the other hand the mucilage
containing the enzymes are protected against getting washed away by
rain.
|