Mandy Tracey: Flesh eating plants of the bog
Keeping up with the Halloween themed blog post by Fearghal, I thought it would be quite fitting to write about flesh eating plants of the bog. Yes I did say flesh eating plants but unless you are a small to medium sized insect I would say your flesh is safe (unless a bright meteorite shower reigns down upon earth causing half the population to go blind allowing the rise of new aggressive carnivorous plant species). There are four species of carnivorous plants in Ireland the purple pitcher plant (Sarracenia purpurea) which was introduced in 1906 and three native plants the bladderwort (Utricularia), butterwort (Pinguicula) and the sundew (Drosera). For this post I will focus on my two favourite flesh eating plants the sundew and the bladderwort.
The bog environment can be a tough place to live especially if your a plant. Many of the nutrients which plants need to survive are in short supply. Carnivorous plants have evolved to cope with this problem by absorbing vital nutrients from the flesh of insects. Now whoever said plants were’nt cool.
Fastest predator of the plant world
Bladderworts are active trappers which means they have moving parts with which they trap their prey. The plant gets its name from its bladder-like traps which are actually modified leaves. Four species of bladderwort are found in Ireland all of which are submerged aquatic species;The common bladderwort (Utricularia vulgaris), intermediate bladderwort (Utricularia. intermedia), Lesser Bladderwort (Utricularia minor) and Southern bladderwort (Utricularia australis). These free floating rootless plants consist of a submerged network of hair-like leaves on which the sack-like traps are produced and protruding above the water surface on a tall stem is the bright yellow flowers which are pollinated by such insects as bees and hoverflies.
I highly recommended the video below which provides a great insight into to how the bladderwort traps works
Sundew plants (Drosera)
Another active trapper the Sundew (Drosera) . The leaves of sundew are covered with up to 200 tentacle-like appendages. At the top of each tentacle is a circular gland which mimics glistening dew. Evidence suggests that the insects are attracted to the colour, scent and the glistening appearance of the leaves. An insect mistakes the dew-like glands for nectar and unsuspectingly lands on the plant and becomes trapped by the sticky secretion. As the fly tries to free itself the movements signals the rest of the tentacles to fold over on themselves further trapping the insect. The tentacle’s glands secrete enzymes that slowly dissolve the flesh of the insect. All that remains is the chitinous skeleton.
See the time lapse video below of a sundew plant digesting its prey.
There are three species of sundew plants in Ireland. All three plants have reddish coloured leaves that develop a rosette shape at the base of the plant from which the flowering stem of tiny white flowers arise. These are Round-leaved sundew (Drosera rotundifolia), Great-leaved (Drosera anglica), and oblong-leaved (Drosera intermedia). Drosera rotundifolia is the most common sundew species. The plant gets its name from the rounded shape of its leaves. D. rotundifolia is not too picky when it comes to its preferred habitat; it can be found on wetter parts of the bog growing amongst Sphagnum moss species but also occurs on the dry bare peat of disturbed areas. Great-leaved sundew (Drosera anglica), is much less common than the round-leaved sundew. The conspicuous leaves of D. anglica are long and narrow and stand higher above the ground than the other two species. D. anglica prefers the waterlogged habitats of blanket and raised bogs, where the water table is at or almost at surface level. Oblong-leaved sundew (Drosera intermedia) is often mistaken for D. anglica due to the similar shaped leaves but is much smaller in size. D. intermedia also differ from the other two in that the stem of the flower grows from the side of the rosette instead of the centre.