Pitcher plant (Nepenthes ovata)

Description

Pitcher plant fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
• Print factsheet

Pitcher plant description

This spectacular carnivorous plant traps and digests invertebrates in large, colourful pitcher-shaped leaves. Nepenthes ovata is a vine with modified pitcher-shaped leaves hanging from coiled tendrils, which either climbs up small trees to a height of about five metres or creeps along the ground depending on the surrounding vegetation ⁽²⁾. Nepenthes species usually have two or three different types of pitcher, generally known as upper and lower pitchers ⁽⁴⁾. In Nepenthes ovata the lower pitchers are trumpet-shaped and green, occasionally blended with red, with a dark red rim that may be streaked with green. The upper pitchers are broadly cylindrical and are yellow with a red rim and yellow stripes ⁽²⁾. Insects and other invertebrates fall into the pitchers, which contain an acidic fluid secreted by the many glands that cover the inside surface of the lower half of the pitcher ⁽⁴⁾. The smooth and waxy upper inner surface of the pitcher makes it impossible for captive insects to gain a foothold ⁽⁴⁾, and a ridge of hardened tissue lining the mouth of the pitcher, the peristome, bears pronounced downward pointing teeth, also preventing insects from escaping. A lid overhanging the mouth of the pitcher prevents rain water from diluting the pitcher fluid ^{(2) (5)}.

Size

Length: up to 5m ⁽²⁾

Pitcher height: 10 – 15 cm ⁽³⁾

Pitcher width: 5 – 6 cm ⁽³⁾

Pitcher plant biology

Pitcher plants are dioecious meaning that male and female flowers grow on separate plants ⁽⁷⁾, and only begin to flower once the upper pitchers are produced ⁽⁶⁾. The flowers produce large amounts of nectar during the early evening and night, which evaporates by morning. This nectar attracts flies during the early evening and moths at night to aid pollination. Once fertilised, a fruit usually takes about three months to develop and ripen. The fruits of Nepenthes species produce between 100 and 500 very light, winged seeds, which can measure up to 30 millimetres long, and are thought to be dispersed by the wind ^{(2) (5)}. Despite enormous numbers of seeds being produced, only a few manage to germinate and only a fraction of those survive to maturity ⁽⁵⁾.

Carnivorous pitcher plants are adapted to grow in soils low in nutrients. Although the plants do gain some nutrition through the soil, and energy through photosynthesis, they supplement this with a diet of invertebrates, usually consisting of ants, cockroaches, centipedes, flies and beetles ⁽⁷⁾. Insects are attracted to the pitchers by their bright colours and nectar, which is secreted by glands situated on the lid and the peristome of the pitcher. The insects fall into the acidic fluid at the base of the pitcher and, unable to escape, they drown. Digestive enzymes are then released to break down the captured prey ⁽⁷⁾.

Despite the hostile environment of the pitchers, they can be home to number of animals. The red crab spider (Misumenops nepenthicola) inhabits pitcher plants in Malaysia, Indonesia and Singapore. This spider ambushes insects that crawl into the pitcher, and preys upon other insects, such as mosquitoes, as they emerge from larvae that live in the pitcher fluid ⁽⁵⁾.

Pitcher plant range

Endemic to Mount Pangulubao and Mount Lubukraya in northern Sumatra, Indonesia ^{(2) (6)}.

Pitcher plant habitat

Found in wet, mossy forest at an altitude of 1,800 metres, Nepenthes ovata is often found growing amongst Sphagnum moss with the vines climbing into small trees if they are growing in the area. Nepenthes ovata tends to creep along the ground on Mount Pangulubao and grows primarily as an epiphyte on Mount Lubukraya ^{(2) (6)}.

Pitcher plant status

Classified as Vulnerable (VU) on the IUCN Red List 2007 ⁽¹⁾, and listed on Appendix II of CITES ⁽⁴⁾.

Pitcher plant threats

Tropical pitcher plants, such as Nepenthes ovata, are threatened primarily from habitat destruction, but due to their low numbers, collecting has also had serious impacts on the population ⁽²⁾. In Indonesia, habitat destruction is a major problem as a result of illegal and commercial logging and large agricultural projects, such as rubber and oil palm plantations ⁽⁸⁾. Sumatra has a very high rate of habitat loss, with some areas losing up to 65 percent of their forest cover in the last 25 years ⁽⁹⁾. Only 33.8 percent of Sumatra remains covered by primary forest, and only 1.3 percent of this is upper montane vegetation, in which Nepenthes ovata is found. The highly localised distribution of this Nepenthes species makes it particularly susceptible to the impacts of habitat disturbance or catastrophic environmental events, such as drought or fire. In addition, highland plants, such as Nepenthes ovata take longer to recover than lowland plants from any disturbance, as growth is slower ⁽²⁾.

Pitcher plant conservation

All Nepenthes species are listed on Appendix II of the Convention on International Trade in Endangered Species (CITES) restricting international trade. However, the incidence of illegal trade in Nepenthes is high, as it is very difficult to regulate and Nepenthes species do not need to be labelled down to species level. Urgent attention is required to remedy this and other trade loopholes ^{(2) (5)}. Nepenthes species, including Nepenthes ovata, are being increasingly cultivated, which helps to reduce the impact on wild populations. Conservation efforts can be made more effective, not only by the implementation and enforcement of protective laws, but also by the encouragement of artificial propagation and establishment of habitat reserves ⁽¹⁰⁾.

Find out more

For more information on Nepenthes species see:

• Clarke, C. (2001) Nepenthes of Sumatra and Peninsular Malaysia. Natural History publications, Kota Kinabalu, Malaysia.

Authentication

Glossary

Carnivore

Flesh-eating.

Endemic

A species or taxonomic group that is only found in one particular country or geographic area.

Enzymes

Proteins that trigger, or accelerate, activity in the cells of the body, for example, breaking down foods during digestion, and building new proteins..

Epiphyte

A plant that uses another plant, typically a tree, for its physical support, but which does not draw nourishment from it.

Fertilisation

In a flowering plant, fertilisation is the process of a pollen grain joining with the ovule (female egg cell). After fertilisation, the female parts of the flower develop into a fruit.

Invertebrates

Animals with no backbone.

Larvae

Stage in an animal’s lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.

Photosynthesis

Metabolic process characteristic of plants in which carbon dioxide is broken down, using energy from sunlight absorbed by the green pigment chlorophyll. Organic compounds are made and oxygen is given off as a by-product.

Pollination

The transfer of pollen grains from the stamen (male part of a flower) to the stigma (female part of a flower) of a flowering plant. This usually leads to fertilisation, the development of seeds and, eventually, a new plant.

Primary forest

Forest that has remained undisturbed for a long time and has reached a mature condition.

References

1. IUCN Red List (April, 2008)
   http://www.iucnredlist.org
2. Clarke, C. (2001) Nepenthes of Sumatra and Peninsular Malaysia. Natural History publications, Kota Kinabalu, Malaysia.
3. Nerz, J. and Wistuba, A. (1994) Five new taxa of Nepenthes (Nepenthaceae)from north and west Sumatra. Carnivorous Plant Newsletter, 23(4): 101 - 114.
4. CITES (April, 2008)
   http://www.cites.org
5. Clarke, C. (1997) Nepenthes of Borneo. Natural History Publications, Kota Kinabalu, Malaysia.
6. Jebb, M. and Creek, M. (1997) A skeletal revision of Nepenthes. Blumea, 42: 1 - 106.
7. Shiva, R.G. (1984) Pitcher Plants of Peninsular Malaysia and Singapore. Maruzan Asia Pte Ltd, Singapore.
8. Mittermeier, R.A., Gil, P.R., Hoffmann, M., Pilgrim, J., Brooks, T., Mittermeier, C.G., Lamoreux, J. and Da Fonseca, G.A.B. (2004) Hotspots Revisited. CEMEX, Mexico City.
9. Uryu, Y. (2008) Deforestation, Forest Degradation, Biodiversity Loss and CO2 Emissions in Riau, Sumatra, Indonesia. WWF Indonesia Technical Report, Jarkata, Indonesia. Available at:
   http://www.panda.org/news_facts/newsroom/index.cfm?uNewsID=125741
10. Wild Borneo (May, 2008)
    http://www.wildborneo.com.my/articles/art_nos_con.html