Carnivorous Plants Honor

Nature Study

Requirements

1. What are the characteristics of a carnivorous plant that differentiate it from normal plants?

   Answer: They capture and digest small animals to supplement N in poor soil. They have specialized traps (snap trap, pitcher, mucilage) and digestive enzymes. Mixed nutrition (photosynthesis + meat). — A concept defined by Charles Darwin in 'Insectivorous Plants' (1875). There are ~700 species in 12 genera. They live in acidic soils poor in N. The best known: Dionaea (Venus flytrap), Drosera, Nepenthes, Sarracenia, Pinguicula, Utricularia. Brazil has 50+ native species (cerrado, pantanal).

2. What are the special care measures that must be taken in handling and conserving carnivorous plants?

   Answer: Distilled or rainwater (tap water has toxic chlorine). Substrate of peat+perlite (no fertilizer). Direct morning sun or indirect. High humidity (60%+). Do not touch the traps (it wastes energy). Do not fertilize (it kills them). They capture on their own; feeding is unnecessary. — Chlorine/fluoride from the tap kill them in weeks. Sphagnum peat maintains pH 4-5 (acidic). Fertilizer causes rotting. A Dionaea closes ~5x before the trap dies. A single insect: 1 fly/month is enough. Perlite facilitates drainage. Vermiculite and sand also work if mined.

3. Conduct research and establish the relationship between: the flowers of carnivorous plants, the pollination process and the insects they feed on.

   Answer: The flowers of carnivorous plants grow on long, tall stems, well away from the traps. This avoids a biological conflict: if the flowers were near the traps, the plant would capture precisely the pollinating insects it needs to reproduce. Thus, there is a separation of functions: 1) Pollination - showy flowers, with nectar and fragrance, attract pollinators (bees, butterflies, wasps) that fertilize the plant and ensure seeds; 2) Feeding - the traps, at the base or in another part, capture prey such as flies, ants, mosquitoes, beetles and spiders to obtain nitrogen. When they flower, many species even reduce the activity of the traps. Result: the insects that pollinate (needed alive) are, in general, different species from those that serve as food (captured and digested). — An evolutionary adaptation called 'spatial separation': the trap below (red, attractive to prey), the flower on top (visible to bees). Drosera has a 30cm stem. Sarracenia has a pendular flower 50cm above the pitcher. Research (Anderson 2010) shows pollinators are distinct from prey.

4. Describe the characteristics of the 4 main families of carnivorous plants below, describing their species, the names of some specimens, places of origin and the characteristics that define them:
   • Nepenthaceae
   • Sarraceniaceae
   • Droseraceae
   • Lentibulariaceae

   Answer: The 4 main families of carnivorous plants: 1) Droseraceae - includes Drosera (sundew, worldwide distribution, a sticky trap with tentacles covered in mucilage) and Dionaea muscipula (Venus flytrap, native to the Carolinas/USA, a snap trap that closes); 2) Nepenthaceae - genus Nepenthes (pitchers hanging, from Southeast Asia, Borneo, Sumatra and Madagascar; the prey falls and drowns in the digestive liquid); 3) Sarraceniaceae - includes Sarracenia (upright pitchers from North America/Carolinas), Darlingtonia (cobra plant, California/Oregon) and Heliamphora (the tepuis of Venezuela); a tubular pitcher trap; 4) Lentibulariaceae - includes Pinguicula (butterwort, sticky leaves, temperate and tropical regions) and Utricularia (bladderwort, aquatic/of moist soil, worldwide, a vacuum suction trap - the fastest in the plant kingdom). Common characteristic: they capture and digest prey to obtain nutrients (especially nitrogen) in poor soils. — Nepenthes rajah (Borneo) has a 35cm pitcher with 3.5L; it eats rats. Sarracenia purpurea is the symbol of New Hampshire. Dionaea muscipula has only 1 species (Venus flytrap). Utricularia macrorhiza lives in still waters. Drosera capensis (Cape sundew) is the most cultivated. Brazil has 30+ native Drosera.

5. An interesting mechanism is how they use traps to capture their prey. Describe each of them, identifying the species mentioned in the previous item:
   • "Snap" type traps
   • Suction traps
   • Sticky leaves
   • Pitchers
   • Other forms

   Answer: 1) "Snap trap" mechanisms: the plant has leaves modified into two lobes with cilia on the edge; when the prey touches the sensitive hairs, the lobes close quickly like a trap. Example: Dionaea muscipula (Venus flytrap), which closes in about 0.1 second. 2) Suction traps: small utricles (bladders) with an internal vacuum; when the prey touches them, the "trapdoor" opens and the water is sucked in along with the animal, in one of the fastest movements in the plant kingdom. Example: Utricularia, which captures aquatic microorganisms in about 0.5 milliseconds. 3) Sticky leaves: leaves covered with glands that produce a sticky substance where the prey gets stuck and is then digested. Examples: Drosera (with dew-like droplets) and Pinguicula (with mucilage on the leaf surface). 4) Pitfall traps (pitcher-shaped trap): leaves modified into "pitchers" with digestive fluid at the bottom; the insect slides down the smooth walls and falls inside, unable to get out. Examples: Nepenthes and Sarracenia. 5) Other forms: spiral or lobster-pot type traps, with hairs pointing inward that lead the prey along a single path with no return. Example: Genlisea, whose Y-shaped underground leaves have a trap-mouth through which the prey enters but does not escape. — Dionaea has the fastest movement in the plant kingdom; it needs 2 touches on the cilia to close (avoiding closing due to rain). Utricularia is even faster (0.5 ms). Drosera has sticky cilia with mucilage (90% water + glycoproteins). Genlisea (Lentibulariaceae) was discovered to be a trap in 2007.

6. What is the "digestion" process of these plants and how do they obtain the necessary nutrients from the insects?

   Answer: After capturing the prey, specialized glands on the surface of the trap secrete digestive enzymes (proteases, lipases, phosphatases, chitinases) and acids that dissolve the soft parts of the insect. Digestion occurs inside the trap (a modified leaf) and generally takes from a few days to 1-2 weeks. The same structures, or nearby absorption glands, then absorb the released nutrients - mainly nitrogen, but also phosphorus, potassium and other minerals - which the plant cannot obtain in sufficient quantity from the poor soil where it lives. The chitin exoskeleton, which is not fully digested, is discarded, washed away by the rain or accumulated in the trap. These nutrients complement photosynthesis (mixed nutrition): the plant produces sugars from light and obtains the scarce minerals from the insects. — Enzymes similar to those of the human stomach (pepsin). Acidic pH (~3) accelerates digestion. Some species use symbiotic bacteria (Sarracenia). Nepenthes alba digests in 2 days. The insect provides essential N in nutrient-poor soil. The Adlassnig study (2011) maps 25+ enzymes in different species.

7. Do one of the following items:
   • Have a properly cataloged collection of at least 3 different (natural) species, mentioning for each one the common name, scientific name, family, and other details about the species.
   • Put together an album with photos of at least 15 different species, mentioning for each one the common name, scientific name, family, and other details about the species. They may be cataloged in digital format (slide presentation) or in physical copy (printed).
   • Cultivate a carnivorous plant of any species for at least 3 months and make a report indicating what the daily care requirements are.

   Answer: Option 1: 3 cataloged species (popular name, scientific name, family). Option 2: a digital or printed album with 15 identified photos. Option 3: cultivate 1 plant for 3 months + report. — A collection with Drosera capensis, Dionaea muscipula, Sarracenia purpurea (the most common in Brazil). The album can use Pinterest or free images from Wikimedia. Cultivating Dionaea is easier in a terrarium with a lid (humidity). Note the waterings, sun exposure, and growth in a journal. CITES protects some species.