| Mouse-trap Plants in Singapore |
| An
environmental education article contributed by Dr. Tan Wee Kiat There is an increasing interest in Singapore in cultivating unusual plants, both local and exotic, as a hobby. These unusual plants include carnivorous plants. Carnivorous plants are able to capture and digest small animals, such as insects and insect larvae. The method of capture varies from the pitfall trap, where the victim is lured into a "pit", to spring traps, such as the steel-trap and mouse-trap, where the victim itself activates the trapping mechanism. The different kinds of traps are summarised below. Genus (common name) Nature of trap |
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Nepenthes (Tropical pitcher plant) Pitfall
Sarracenia (North American pitcher plant) Pitfall
Heliamphora (South American pitcher plant) Pitfall
Pinguicula (Butterwort) Fly-paper
Drosera (Sundew) Fly-paper
Dionaea (Venus fly-trap) Steel-trap
Utricularia (Bladderwort) Mouse-trap
Among these different plants many scientists consider the traps of Utricularia (Bladderwort) to be the most unusual due to their intricate mechanism and tiny size. The tiny trap is usually smaller than the size of a match-head.
In Singapore there are several species of Utricularia growing in the sunny vicinity of reservoirs and ponds, and seasonally-wet areas. These amazing plants are however not well-known to the public due to their small, and hence easily overlooked, size. So far, we have seen Utricularia bifida, U. caerulea, U. gibba, and U. minutissima (photo above) on our nature walks.
Under the microscope the traps look like small bladders or bags ("utricle" is derived from the Latin name for "bag"). One part of the bladder is attached to the stem. Another part of the bladder has outward-pointing hair triggers. When these hair triggers are touched by small prey, such as the larvae of tiny insects, the bladder expands suddenly and the prey is sucked in. The action takes place very fast, in a fraction of a second. The bladder then digests the prey.
After digestion, the trap opens again and is ready for the next victim. The traps function only in water. In seasonally-wet areas the plants die when the ground dries out. When the rainy season comes round again the seeds that were produced earlier will then germinate.
An additional bonus from theses plants is that their tiny flowers are very attractive. One species, Utricularia minutissima, has flowers that will remind you of the cartoon character Donald Duck!
Reference:
Tan T.W.H (1997) A guide to the Carnivorous Plants in Singapore, Singapore Science Centre.
Taylor, P. (1989) The Genus Utricularia - a taxonomic monograph. Her Majesty’s Stationery Office, U.K.