Drosera also referred to as sundews, is one of the largest genera of insectivores (carnivorous) plants, with at least 194 species. These members of the Droseraceae family use stalked mucilaginous glands on the surface of their leaves to attract, catch and eat insects. The insects are utilized as a supplementation to the plants' inadequate mineral nutrition in the soil. All continents, with the exception of Antarctica, are home to a variety of these species that differ widely in size and form. Their leaves develop long tentacles, each of which has a sticky gland at the tip. This article will explain to you about Drosera or Sundew which will be helpful in preparing the Environment Syllabus for the UPSC Civil Service exam.

What are Insectivorous Plants?

• These plants are commonly referred to as insectivorous plants since they are excellent at trapping insects.
• They have a totally distinct way of nutrition from normal plants. However, they never prey on people or big animals.
• Based on how they get their food, insectivorous plants can be roughly categorized as either active or passive varieties.
• When insects settle on their leaf traps, the active ones can immediately seal them.
• The passive plants feature a device known as a "pitfall," which resembles a jar or pitcher and into which an insect can fall and finally be digested.
• The insectivorous plants frequently use a variety of lures, including vivid colors, delicious secretions, and other curiosities, to entice unwitting victims.

Drosera - Distribution

• This genus is frequently referred to as cosmopolitan, which denotes its global range.
• The sundew genus is distributed from Alaska in the north to New Zealand in the south.
• The most diverse regions are Australia, which is home to over half of all species now recognized, South America, which has over 20 species, and southern Africa.
• A few species can also be found throughout significant portions of North America and Eurasia.
• But because sundews normally do not approach temperate or arctic regions, these regions can be thought of as being on the periphery of the general range.
• The species is believed to have originated on the continents of Africa and Australia.

Drosera - Habitat

• Sundews typically grow in habitats with acidic soils, high levels of sunlight, and seasonal or, less frequently, year-round moisture.
• Bogs, fens, swamps, marshes, the tepuis of Venezuela, the wallums of coastal Australia, the fynbos of South Africa, and wet streambanks are examples of common habitats.
• Many of these species coexist with sphagnum moss, which significantly reduces the amount of nutrients accessible to plant growth by absorbing them and acidifying the soil.
• This enables sundews, which do not depend on nutrients in the soil, to thrive in areas where more invasive vegetation would typically outcompete them.

Drosera - Physical Description

• The plants have tiny, nodding, five-petaled white or pinkish flowers that are carried on one side of a curved stalk about 10 to 25 cm (4 to 10 inches) above the basal leaves.
• Drosera are mostly perennials meaning they live more than two years.
• Less than 2.5 cm (1 inch) in diameter, the leaves are typically grouped in a rosette.
• Flexible gland-tipped trichomes (plant hairs) that emit a sticky material to attract and entrap insects and other tiny animals cover the upper surface.

Drosera - Insect Trapping Mechanism

• The tentacles on the leaves produce a sticky liquid that sparkles like dew drops in the sunlight. As a result, the Drosera are frequently referred to as sundews.
• An insect that has been attracted by these glittering drops lands on the surface of a leaf.
• Prey that has been caught is engulfed in a web of the sticky glands, also referred to as tentacles, and is then broken down by enzymes.
• The leaf unfolds after digestion to reset the trap.

Drosera - Conservation Status

• Drosera is threatened with extinction on a global scale as a result of the loss of its natural environment due to urban and agricultural development.
• Additionally, they face danger from the unreported harvesting of wild plants for the horticultural industry.
• Because species are frequently specifically suited to a particular area and set of characteristics, environmental change is another risk.
• Wetland habitat loss is currently the biggest danger in Europe and North America.
• Drosera species are found throughout South America and the Caribbean, and some regions are deemed critical, endangered, or vulnerable, while other regions have not been examined.
• New species are constantly being found in the Western Cape and Madagascar while species are in danger in South Africa.
• By drying up previously damp places, the droughts that have been ravaging Australia for the past ten years also represent a threat to numerous species.

Drosera in India

• Drosera or sundew thrive in marshy or moist infertile soils.
• The single species of Aldrovanda, a rootless, free-floating aquatic plant, is found in the salt marshes of the Sundarbans, south of Calcutta.
• It can also grow in bodies of fresh water like lakes, tanks, and ponds.
• A sundew that is native to India, Africa, and Australia, is the flycatcher.
• It is an annual, unbranched herbaceous plant with a fibrous root structure that can grow to a height of 5 to 50 cm.
• Only the most recent growth of older plants has an upright tendency; younger plants stand upright.
• The plant can range in color from maroon to yellow-green. On top of stems, inflorescences are 50 cm long and have 3 to 25 flowers.
• When the summer wet season begins, seeds naturally sprout. September is their flowering season.

Drosera - Uses

As a Medicinal Plant

• As early as the 12th century, an Italian physician from the School of Salerno named Matthaeus Platearius reported sundews as a therapeutic herb for coughs under the name herba sole.
• Recent research has demonstrated that drosera has anti-inflammatory and antitussive properties.
• The self-repair mechanisms of bronchial epithelial cells may be stimulated by drosera to aid in the treatment of respiratory illnesses, according to some research.
• Drosera is used to treat conditions like stomach ulcers, lung infections, coughs, and asthma. Additionally, it might be anti-fertility.
• Milk can be curdled by Drosera, whose bruised leaves are applied to blisters and used to color silk.

As an Ornamental Plant

• Sundews have gained popularity as decorative plants due to their carnivorous habits and the attractiveness of their glistening traps.
• As a result, the majority of species are not available for purchase. However, a few of the hardest varieties have entered the mainstream nursery industry and are frequently offered for sale next to Venus flytraps.
• Among these, D. capensis, D. aliciae, and D. spatulata are most frequently found.

Nanobiotechnology

• Drosera is a very attractive research subject for biomaterials because of the amazing elastic capabilities of its mucilage. In a recent study, the content of nanofiber and nanoparticles in the sticky mucilages of three species (D. binata, D. capensis, and D. spatulata) was examined.
• The mucilage leftovers contained networks of nanofibers and nanoparticles of various sizes, which the researchers were able to see using atomic force microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy.
• In addition, the essential elements of biological salts, calcium, magnesium, and chlorine, were found.

Other Uses

• The Australian Aboriginals regard the corms of the native tuberous sundews as a delicacy.
• While another purple or yellow dye was customarily created in the Scottish Highlands using D. rotundifolia, some of these corms were also used to color fabrics.
• A 14th-century recipe is still used today to make a sundew liqueur.
• Fresh leaves primarily from D. capensis, D. spatulata, and D. rotundifolia are used to make it.

Conclusion

Events that change the hydrologic function of fens provide the greatest threats to Drosera. Their ecosystem function and floristic composition may be affected by activities that interfere with, redirect, increase, or redistribute groundwater or surface flow to and through it. Other stress may result from activity in nearby ecosystems, such as logging, fires, road construction, diverting surface flow, and groundwater pumping. Thus, maintaining the groundwater and surface water flow regimes is the essential factor to be taken into account when making conservation decisions for Drosera. This calls for a thorough understanding of the hydrologic processes at the locations where Drosera is found.

FAQs

MCQs

1. What is the primary method through which Sundews capture their prey?

A) By using their roots
B) Through sticky glandular hairs on their leaves
C) By emitting a strong scent
D) Through mechanical traps

2. Where is Drosera commonly found?

A) Arid deserts
B) Tropical rainforests
C) Wetlands, bogs, and swamps
D) Temperate grasslands

3. What type of plant is Drosera?

A) Non-vascular plant
B) Carnivorous plant
C) Medicinal plant
D) Flowering tree

4. Which of the following is a common species of Sundew?

A) Drosera capensis
B) Drosera affinis
C) Drosera gigantea
D) Drosera sativa

5. Why are Sundews important to their ecosystem?

A) They provide habitat for animals
B) They increase the soil's nutrient content
C) They help maintain nutrient balance by digesting insects
D) They produce oxygen in large amounts

GS Mains Questions and Model Answers

Q1: Discuss the ecological role of carnivorous plants, particularly Sundews, in their habitats. How do they contribute to maintaining the balance in nutrient-poor environments?

Answer: Carnivorous plants, including Sundews, play a significant role in nutrient-poor ecosystems such as bogs and wetlands. These plants are adapted to obtain essential nutrients like nitrogen and phosphorus by capturing and digesting insects. In environments where the soil lacks these nutrients, carnivorous plants serve as a natural mechanism for nutrient cycling. By digesting prey, they provide a steady source of nitrogen to themselves, which would otherwise be scarce. This process helps maintain the balance in the ecosystem, contributing to the overall health of the plant community. Additionally, by capturing excess insects, Sundews help regulate insect populations, preventing overgrowth and ensuring biodiversity in their habitats.

Q2: Explain the adaptations of Drosera (Sundew) that allow it to survive in nutrient-poor soils. How do these adaptations benefit the plant?

Answer: Drosera, or Sundew, is specially adapted to survive in nutrient-poor, acidic soils by developing carnivorous characteristics. The plant produces sticky glandular hairs on its leaves, which secrete a viscous fluid that traps insects. These adaptations help Sundew obtain essential nutrients like nitrogen, phosphorus, and potassium, which are otherwise limited in its environment. The ability to digest insects allows the plant to supplement its nutrient intake and thrive in soil that would be insufficient for other plants. Additionally, the plant's slow growth and ability to store nutrients help it conserve energy and survive in harsh conditions. These adaptations make Drosera one of the most efficient nutrient-gathering plants in its ecosystem.

Q3: Analyze the impact of Drosera (Sundew) on the insect populations in their environment. What role does this plant play in maintaining ecological balance?

Answer: Drosera, through its carnivorous nature, plays an essential role in controlling insect populations in its habitat. By capturing and digesting insects, Sundews help regulate the abundance of certain insect species, preventing overpopulation and the potential destruction of other plant species. This natural pest control is particularly important in nutrient-poor environments, where Sundews help balance the ecosystem by managing insect populations. The presence of Sundews can also contribute to the diversity of other species by maintaining a healthier and more stable environment. Additionally, the nutrients absorbed from insects support the growth of Sundews, which in turn sustains the plants that rely on them for their survival.

Previous Year Questions on Drosera (Sundew)

1. UPSC CSE Prelims 2021:

Question: Drosera, commonly known as Sundew, is a:

A) Flowering plant
B) Carnivorous plant
C) Medicinal plant
D) Non-vascular plant

Answer: (B)

Explanation: Drosera, or Sundew, is a carnivorous plant that catches and digests insects for essential nutrients like nitrogen and phosphorus, which are scarce in its habitat.

2. UPSC CSE Mains 2020 (GS Paper 3):

Question: "Discuss the importance of carnivorous plants like Drosera in maintaining the balance of nutrient-poor ecosystems. How do they contribute to biodiversity?"

Answer: Carnivorous plants like Drosera play a vital role in nutrient-poor ecosystems by capturing and digesting insects, thus supplementing their nutrient intake. This helps regulate insect populations and supports nutrient cycling in the soil. By doing so, they prevent overgrowth of insect populations that could otherwise damage plant life, thus maintaining ecological balance. Sundews also help promote biodiversity by creating microhabitats for other organisms and contributing to the overall health of the ecosystem.