Why Do Pitcher Plants Eat Insects? An Explanation of the Reasons
Pitcher plants are the collective name for all species in the genus Nepenthes. They are tropical carnivorous plants, native mainly to the tropical regions of the Old World. Their leaves have a complex structure, divided into petiole, leaf blade and tendril. The inner surface of the pitcher's lid can secrete a fragrance to lure insects, and the tendril's tip expands and curls back to form a pitcher that can capture insects. Let's take a look below at why pitcher plants eat insects!
Why do pitcher plants eat insects?
Most pitcher plants live in environments with relatively high humidity and temperature and bright diffused light, generally at the edges of forests or shrublands or in open areas. A few species, such as Nepenthes ampullaria, prefer to grow in dense, shady forests, while most species have adapted to growing among grassland-type plant populations. The reason they eat insects is that pitcher plants originally lived in extremely harsh environments and could only survive by preying on insects, and this behavior gradually evolved into their habit.
How do pitcher plants capture insects?
The pitcher's insect-trapping trap has a rather special structure, and the inner wall of the pitcher has a lot of wax and is very smooth. On the inner wall there are about 1 million digestive glands, which, after the pitcher plant catches an insect, can secrete a large amount of colorless, transparent, slightly fragrant acidic digestive fluid. This digestive fluid contains amines and coniine that can paralyze and poison insects. At the same time, on the inner side and the edge of the pitcher's lid there are many nectaries that can secrete fragrant, sweet nectar to lure insects. When the pitcher opens this honey-pot lid, it attracts many greedy small insects. Once a small insect falls into the pitcher, the lid will immediately close automatically, and the insect quickly dies from poisoning. Before long, all its body parts are digested and absorbed as nutrients by the pitcher plant.
What growing conditions do pitcher plants need?
1. Light: Light is one of the most important factors in growing huge and brightly colored pitcher traps. Providing sufficient air humidity, moderate soil moisture and ample light can make the leaves take on a red like red wine. The plant can be acclimated to accept some direct sunlight, preferably morning sunlight; by contrast, full sun will make the plant's color dull and hinder the plant's growth.
2. Water: Unlike other carnivorous plants that only need the soil kept moist during the growing season, pitcher plants need the soil kept constantly moist when cultivated, and the growing medium should preferably be loose and not squeeze out water. Therefore, watering is more suitable for pitcher plants. However, the immersion method can still be used to supply water, only the air permeability of the growing medium needs to be improved by increasing the proportion of large-particle growing medium, so as to avoid the growing medium becoming too wet.
3. Humidity: The level of air humidity is the key factor affecting whether pitcher plants can normally produce pitchers. Under natural conditions, pitcher plants usually grow in relatively humid areas, with humidity of at least 60%. Therefore, in cultivation, many people always encounter the problem that pitcher plants cannot grow new pitchers, and the pitchers often wither as if scorched before they have even grown large. In most cases, the reason pitcher plants do not grow pitchers is that the environment is too dry.
4. Temperature: Pitcher plants are distributed across a very wide range of altitudes, from flat ground to high mountains above 3,000 m in elevation. In horticulture, they are divided into two major categories, highland species and lowland species, according to their altitudinal distribution. Pitcher plants growing in high mountains above 1,200 m in elevation are highland species, with cultivation temperatures of 21°C during the day and 10°C at night. Pitcher plants growing on flat ground or in areas below 1,200 m in elevation are lowland species, with cultivation temperatures of 29°C during the day and 21°C at night.
5. Nutrition: Pitcher plants are carnivorous plants and already have the ability to obtain nutrients by capturing insects or small animals; these carnivorous plants are all very efficient insect catchers. Cultivating pitcher plants does not require specially feeding them insects, and pitcher plants cultivated outdoors can usually catch insects on their own. Whether regularly providing them with some insects would make them healthier, make their pitcher traps larger, or make them more cold-resistant has not yet been proven by sufficient evidence.