The promotional blurb for Eanna Ni Lamhna’s “Wonders of the Wild” children’s book mentioned “animal-eating plants”. That is not something I hear about every day so I decided to research the marvel.
It is strange but true that plants eat animals. Charles Darwin spent 16 years observing experiments he conducted on them. He showed that the leaves of some plants transformed into ingenious structures that trapped insects and other small creatures and then were able to digest them and absorb nutrients released from their corpses. Darwin published his findings in 1880 and generations of biologists since have worked to understand the habits of these plants.
The theory is that these plants have evolved independently as individuals and as groups more than 12 times. They grow in poor soil that lacks the nutrients they need and that was the catalyst for 583 species adapting to carnivory. The number of species had been increasing each year, however, an assessment in 2020 found that about one-quarter are threatened with extinction by human activity.
Carnivorous plants can be found on all continents except Antarctica. They are widely distributed in lakes, streams, waterlogged soils and in bogs in Ireland. We host 11 different species of carnivorous plants, belonging to four distinct groups: sundews (3 species), butterworts (3 species), bladderworts (4 species), and a non-native pitcher plant (1 species). Each uses a different mechanism to catch and digest live prey.
Sundews have spoon-like leaves covered with red tentacles and sticky substance of acidic enzymes to trap insects that mistake it for nectar. The tentacles bend over the fly, midge, beetle or even a damselfly and it cannot escape. Digestive juices are released to kill and dissolve the prey from which the sundew absorbs nutrients such as nitrogen and phosphorous as those are in short supply in the bog.
Butterworts possess the strongest natural glue known. When insects walk on to the leaves the leaves roll in from the edges to prevent its escape.
Bladderwort derives its name from the small hollow bladder-like traps along the stem. The bladder trap door opens when triggered by a worm, water flea or insect larvae. These animals are vacuumed into the bladder in an instant, the trap door shuts and the animal is enzymatically digested. After 15-30 minutes the trap door is reset.
The Canadian Pitcher Plant was planted in a bog in Co. Roscommon in 1906. Since then it has taken root in a dozen bogs throughout the country. Pitcher Plants are complex invertebrate traps. Insects are lured to the green upright tubular leaves by red and purple vein markings and droplets of nectar spiced up with intoxicating narcotic. When it lands the insect loses its footing on a slippery substance and falls down into digestive juices and detergents.
Scientists continue to study carnivorous plants to deepen their understanding of the natural world; such as how plants evolve or adapt to climate and habitat changes. Questions asked of them frequently are:
1) can they be a resource for pharmaceuticals; 2) are they useful herbal medicines; 3) can I use carnivorous plants to get high.
When it comes to pollination of these plants it is done by bees and beetles that are smart enough to avoid the traps which are spaced far enough away from the flower part with the pollen.
Diarmuid Gavin suggested that we grow some carnivorous plants in our gardens because they are fascinating and they may engage youngsters with the wonders of horticulture.
The Bog of Allen Nature Centre has a “Flytraps” Garden of carnivorous plants that is open to visitors.
Back in the 1800s in some cultures history and beliefs were passed on through the oral tradition and one of the things people worshipped was nature and they created myths or folk tales about it. Charles Darwin did research in places where such people lived and he wrote books like “Insectivorous Plants” published in 1875. Some writers of fiction at the time were fascinated by carnivorous plants. H.G. Wells wrote “The Flowering of the Strange Orchid” that had plants turning on humans and eating them. That inspired A.C. Clarke to write “The Reluctant Orchid” in 1956. “The Little Shop of Horrors” was based on that book. The film is a farce about a plant, Audrey 11, which feeds on human blood.