Plant Behavior Overview and Analysis
Scientists continue to discover amazing survival behavior in the plant kingdom as plants demonstrate traits that are commonly associated with the animal kingdom. Some of the recently discovered survival behaviors among plants range from altruism and cooperation to defense and manipulation. However, predation and hunting by plants is an interesting phenomenon since the sedentary plants succeed in capturing fast moving insects and arthropods. The carnivorous plants obtain the necessary nutrients from trapping and eating protozoans, insects, and arthropods. Carnivorous plants use five basic mechanisms for catching their prey, and this includes lobster-pot traps, bladder traps, snap traps, flypaper traps, and pitfall traps. The Venus flytrap (Dionaea muscipula) is the most renowned species of carnivorous plants although hundreds of other carnivorous plants exist. This paper focuses on the Venus flytrap and seeks to elaborate the plant’s distribution, characteristics, common prey, and trapping mechanism other interesting facts about Dionaea muscipula.
Dionaea muscipula belongs to the order Caryophyllales and family Droseraceae (Simpson 2006). The plant shares similar characteristics with Aldrovanda vesiculosa (the waterwheel plant) although the waterwheel plant grows in aquatic environments while the Venus flytrap is a terrestrial plant. The Venus flytrap natural environment is limited to the subtropical wetlands of North and South Carolina although some individuals cultivate the plant in their gardens for aesthetic purposes. The Venus flytrap typically consists of between four and seven leaves arranged in a rosette shape, and the leaves grow from short underground stems. The leaf blades are made of two terminal lobes hinged at the center and heart-shaped petioles used for photosynthesis. The terminal lobes form the plant’s trapping device and contain red anthocyanin pigments that attract prey. Additionally, the terminal lobes produce some nectar to lure the prey to the center of the leaf. The terminal lobes contain three hair-like trichomes on each side and these act as triggers for the closing mechanism. The common preys of the Venus flytrap include arachnids and insects although the plant is capable of trapping anything that fits in the terminal lobes. For instance, researchers have observed the Venus trapping small frogs that are not strong enough to escape from its terminal lobe.
One of the fascinating features of Dionaea muscipula is its highly specialized hair-like trichomes that occur on the upper side of the terminal lobes. The hair-like trichomes can distinguish between non-prey and living prey stimuli despite their high sensitivity to motion (Akhilesh 2008). The evolutionary adaptation of selective is crucial to the plant’s survival because it prevents the leaves from shutting unnecessarily. Each terminal lobe opens and closes approximately seven times before the leaf withers. Consequently, the plant needs to close only when an appropriate prey lands on the leaf surface. The closing of a Venus flytrap’s leaf is one of the fastest motions in the plant kingdom, as the leaves snap shut in approximately less than one second. The terminal lobes usually close when one of the trap hairs is touched twice within twenty seconds or when a prey touches two trap hairs simultaneously (Scott 2013). Such stimuli cause the terminal lobe to snap shut quickly and trap the prey inside the leaf before the Venus flytrap releases its digestive juices.
Each terminal lobe of Dionaea muscipula contains glands that secrete digestive enzymes that decompose the trapped prey. The terminal lobes’ edges have stiff hair-like projections that form a mesh when the leaf closes, and this helps in preventing the captured prey from escaping. However, the mesh is large enough to allow the smaller insects and arthropods to escape. The leaf reopens after some few hours once the smaller insects and arthropods escape. This evolutionary adaptation is important because it prevents the Venus flytrap from expending much energy on small prey that will not provide enough nutrients. The closed terminal lobes tighten each time the trapped prey moves inside and the glands produce additional digestive enzymes to hasten the digestion process (Escalante-Perez et al. 2011) argue that the leaves of Dionaea muscipula stop photosynthesis once the plant captures a prey. This evolutionary adaptation is necessary because it creates anaerobic conditions that kill the prey quickly.
Although researchers have studied Dionaea muscipula extensively, the speed at which the plant traps its prey continues to baffle the scientists. The scientists are yet to understand the mechanism that facilitates such a fast closure of the terminal lobes. However, the scientists agree that rapid closure of the Venus flytrap’s terminal lobes depends on an action potential. Demko et al. (2010) suggest that the reaction occurs due to the activation of mechanosensitive ions when preys stimulate the trigger hairs. The mechanism that causes the Venus flytrap to react quickly to stimuli is comparable to the mechanism that causes muscular movements in animals (Pavlovic et al. 2011). However, researchers continue to investigate on the Venus flytrap’s extraordinary evolutionary adaptations such as its ability to distinguish prey and non-prey stimuli, memory, and rapid movement. The scientists are interested in understanding the chemical processes that make the Venus flytrap one of the enigmatic plants.
Akhilesh T. Longman Science Biology 10. Pearson Education India; 2008. p. 135.
Escalante-Perez M, Krol E, Stange A, Geiger Dietmar, Al-Rasheid K, Hause B, Neher E, Hedrich R. A special pair of phytohormones controls excitability, slow closure, and external stomach formation in the Venus flytrap. Proceedings of the National Academy of Sciences. 2011; 108: 15492-15497.
Demko V, Pavlovic A, Hudak J. Trap closure and prey retention in Venus flytrap (Dionaea muscipula) temporarily reduces photosynthesis and stipulates respiration. Annals of Botany. 2010; 105: 37-44.
Pavlovic A, Slovakova L, Pandolfi C, Mancuso S. On the mechanism underlying photosynthetic limitation upon trigger hair irritation in the carnivorous plant Venus flytrap (Dionaea muscipula Ellis). Journal of experimental botany. 2011.
Scott P. Physiology and Behaviour of Plants. New York, NY: John Wiley & Sons; 2013. p. 320.
Simpson MG. Plant Systematics. Amsterdam: Elsevier/Academic Press; 2006. p. 608.