Venus flytrap – don’t fall into the “trap”!

Venus flytrap (Dionaea muscipula) is the most exciting and popular among all carnivorous plants as it has modified leaves as snap traps. It is under the family of Droseraceae and the only species in its genus. Venus flytraps are native only to the coastal plain of southeastern North Carolina and extreme northeastern South Carolina. It can be found the area with unfavorable conditions such as peaty and acidic soil mostly low nutrient availability in damp that typically exposed to sunny. The growth climate is usually warm temperate and humid. Generally, it can be planted in sphagnum moss (living or non-living) at growing season 70-100 oF (21-38 oC) with dormant season 35-50 oF (1.7-10 oC). It requires relatively high humidity, and the substrate must keep moist all the time. Dionaea plants do well in bright light. For home growers, it must take note of the water source. Water such as rainwater, reverse osmosis (RO) water, and distilled water containing low mineral content (measured in part per million, PPM) are suitable for its growth. Tap water will result in death as carnivorous plants obtain the nutrients through the preys, not from the substrates or water.

Venus flytraps belong to perennial plants that can be grown from seeds. Collectors often cross-pollinate the flowers to obtain hybrids with combined traits for making it more interesting in terms of the colours, sizes, and the shape of the “trap”. One flytrap seedling usually takes about four to five years (or shorter, depends on the varieties) to reach maturity. Then, it can live for many decades with a suitable growth environment. Mature flytraps have a rosette of leaves which differed in diameters (varieties dependent). The leaves consist of two parts namely petiole, an expanded leaf-based, and the “trap”, which is the true leaf. Most of the varieties have the red colour of the inner part of the lobes which the red colouration is controlled by the light intensity of the light source (natural or artificial). The rosette has short and thick rhizome or underground stem with few thick, black, and hairy-look roots that are several inches long. However, flowering in venus flytrap might not be flavoured because it could bring exhausting effect on the plant in cultivation, meaning the flowers “drain” the energy from the plant. The hobbyist who wants to make new hybrids will keep the flowers and cross-pollinate them manually. Otherwise, the flower stalk is suggested to clipped off. Surprisingly, to propagate it through flower stalk cutting is possible! Venus flytrap can be propagated by splitting the offset that produced a clumping of offshoots, but make sure it has complete structures such as the crown of leaves with separate root system before the division was carried out. Moreover, propagation can also be done through leaf-cutting by peeling the leaves off the rhizome with a downward tug with the whitish base of the leaf is intact. The successful regeneration through leaf pulling method is varieties dependent. Throughout the growing period, older leaves will turn black and die, and all the leaves may die off during hard frosts due to dormant (“hibernation”) mechanism in nature.

The active trapping mechanism of the Venus flytrap is the most wonderful and rapid movement in the plant kingdom. The trap consisting of two symmetrical halves or lobes that concave or dished inward with the teethed (or hair-like projection, cilia) margins. The inner base of the teeth consists of glands that produce sweet nectar which lure the insects to drink the nectars. What triggers the closure of the trap is the tiny “hairs” structure located at the center. The insects need to “touch” the tiny hairs (at least two) or one hair twice within twenty seconds to stimulate the trap to “close”. Why exactly twenty seconds needed? This is because the timing helps the trap to differentiate whether the insects or raindrops touched the hairs in nature! External factors such as plant age, ambient temperature, length of time since last closure, as well as the general health of the plant play essential roles in controlling the closing of the traps. Under ideal conditions, the trap closes with alarming speed, a second or less. Studies showed that the traps could be closed in 0.3 seconds.

The trap does not close tightly right away. This is hypothesized that it allowed the escape of small insects so that it would not waste time and energy “eating” an insignificant meal. However, if larger insects or animals such as snails, slugs, tiny frogs were trapped, the more the mechanical stimuli (interaction by the struggling movement with the hairs), the tighter the lobes, until it is sealed itself. Subsequently, the insects or small animals will be drowned by the digestive fluid that containing enzymes to digest them and turning them into their nutrient. The secretion of the enzymes is responded to the entrapment of protein material only. It usually takes four to ten days to digest its prey in which the soft tissues of the prey were dissolved and absorbed by the plant. Once it reopens the lobes, it welcomes second prey to fall into the trap. Second prey such as a spider or large ants often the most frequent “visitors” as they were lured by the dried, shriveled exoskeleton of the remaining bodies. If there is no second prey nearby, the lobes remain open and the residues were washed away by the rain. Remember, do not play with the traps frequently! They used up a lot of energy to catch the preys in which each trap can catch only one to three meals. Failure to do so may result in the death of the leaf and turn black.

Studies proved that fed plants are healthier and produce more seeds than those prey to survive. Some hobbyists feed it with live insects or granular fish food. It is good to have horticultural practice by trimming all dead leaves off from the plants to avoid transmission of diseases by bacteria and fungus. This is also used to avoid the build-up of organic mineral content in the substrate over time. In modern biomedical research, it was found that Dionaea muscipula contains several secondary metabolites with medicinal and therapeutic properties.

Further Reading:

Scala, J., Iott, K., Schwab, D. W., & Semersky, F. E. (1969). Digestive secretion of Dionaea muscipula (Venus’s flytrap). Plant Physiology44(3), 367-371.

Volkov, A. G., Adesina, T., Markin, V. S., & Jovanov, E. (2008). Kinetics and mechanism of Dionaea muscipula trap closing. Plant physiology146(2), 694-702.

Gaascht, F., Dicato, M., & Diederich, M. (2013). Venus flytrap (Dionaea muscipula Solander ex Ellis) contains powerful compounds that prevent and cure cancer. Frontiers in oncology3, 202.

Rahaman, S. T., & Sai, P. R. (2018). A short review on carnivorous plants and recent developments in the field of cancer research. iJP5, 205-12.

Temple, P. (1988). Carnivorous plants.

Pietropaolo, J., Pietropaolo, P. A., & James. Pietropaolo. (1999). Carnivorous plants of the world. Timber Press.

Meyers-Rice, B. (2006). Growing carnivorous plants. Timber Press.

D’amato, P. (2013). The savage garden, revised: Cultivating carnivorous plants. Ten Speed Press.