‘Feed me, Seymour’: the secret lives of carnivorous plants

‘Feed me, Seymour’: the secret lives of carnivorous plants

The idea of a plant eating an animal has always seemed to be a very contradictory notion to me. Plants, generally immobile organisms, catching prey? This very phenomenon, however, is what makes carnivorous plants so fascinating.

There has been many a time when my first thoughts of carnivorous plants have been of Audrey from Little Shop of Horrors: a terrifying, blood-sucking plant that’s hungry for human flesh. With this image in mind, I’ve always imagined real carnivorous plants to be baying for blood or stalking their prey.

‘Feed me, Seymour.’ Image: Tim Green / Flickr

These daydreamed ideas are far from accurate though, given the limitations that plants face as sessile organisms. Carnivorous plants cannot race after food that moves, nor gulp down large chunks of meat. Instead, similar to Audrey, they have developed different means of attracting food to them.

There are numerous carnivorous plants that use bribes to attract their prey. Some use nectar whilst others exude a delicate perfume to entice their victims. Many simply have leaves that are covered with hairs and a sticky substance to catch any unfortunate organisms that stumble across them.

The most recognisable of the carnivorous plants is of course the Venus flytrap. This North American species is cultivated worldwide and is one of a very small group of carnivorous plants that displays rapid movement. This action is triggered by an unfortunate insect stumbling into the Venus’ jaws. Most carnivorous plants don’t have this capacity for quickly catching prey and rely instead on other physiological adaptations to trap their food.

Sticky leaves. Image: Noah Elhardt (Own work) [Public domain], via Wikimedia Commons
Looking at the extremes that these plants go to in order to capture insects, one must ask a simple question – why? The answer to this is based on where most carnivorous plants live. They are found most often in very nutrient-poor soils that contain very low levels of nitrogen and calcium. Very few organisms can survive in such conditions, and so the ability of carnivorous plants to source these nutrients from the insects and spiders they catch enables them to live in such extremes.

Within Australia, the most common family of carnivorous plants is the sundews (Drosera) with 116 different varieties found across the country. This is not unexpected given the extreme conditions of Australian environments and the low nutrient content in many soils.

Drosera aberrans. Image: Sarah Bond

My first experience of seeing a sundew was at a local nursery that had grown some for sale. The scented sundews (Drosera aberrans) that I saw were sitting in small pots and I thought they looked far too delicate to be capturing and eating insects. Like most things in nature though, first impressions are often deceiving. Upon closer inspection, I noticed that there were numerous ants and other insects trapped on the sundews’ sticky leaves, slowly being digested.

Since seeing the scented sundew on this occasion, I’ve had an increased fascination with these plants and their behaviours. Given their main growing season is between autumn and spring, I’m looking forward to watching for the scented sundew, as well as others from the Drosera family, this season.

Banner image courtesy of Sarah Bond.

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