Absorbed in the delights of the feast, the insect wanders with fatal ease down the fluted rim. Once below the inside edge of this, escape is almost impossible, for the border is adorned with sharp, teeth-like processes, all pointing downward to the pit of destruction. Moreover, the inside walls of the pitcher are specially smoothed with a wax-like secretion, which makes climbing up a very difficult feat. Even insects with wings seem to find a great difficulty in making good their escape.
The pitchers of the Nepenthes are usually about half filled with fluid; this is not entirely collected rain or dew, but is largely formed by a definite secretion of the plant. Into this fluid the exhausted insect tumbles sooner or later, there to end miserably among a mass of drowning victims. It has been definitely proved that this fluid is an acid secretion—not unlike the digestive juices of an animal—which enables the plant to extract the nutriment it needs from the bodies of its victims.
THE NEPENTHES CATCH EVEN
MICE AND BIRDS
It is in connection with the fluid contained in the pitchers of the Nepenthes that these plants catch much larger prey than insects. In the tropics it is not always an easy matter for birds and other small animals to secure a drink readily. The half-filled pitchers entice many a small creature to creep over the fluted rim in order to secure a draught of the fluid, which is not unpleasant to the taste. Now and again the venturesome visitor loses his hold and tumbles into the pitcher. Even in the case of mice and small birds the pitcher proves a veritable death-trap. The slippery sides are almost insurmountable, while the sharp hooks round the rim still further check an escape. Sooner or later the victim falls back into the fluid and is drowned. Strange as it may appear, after such a capture the plant grows vigorously, for the decaying body of its victim is rich in just the food material of which it stands in need.
THE DEATH PITCHER OF
THE SARRACENIAS
A very singular group of plants, the Sarracenias, are quite common in the bogs of North America. These are of an elegant shape, and may be as much as one foot or two feet in height. Nearly always they are highly colored, and altogether so attractive do they appear that insects of all kinds simply crowd to them. On arrival at the lip of the pitcher, the insects find a feast of honey spread out for their delectation. With almost devilish ingenuity this becomes sweeter and more plentiful the farther down into the pitcher one traverses. At a certain point, however, the nectar ceases, and the insect thinks that he will retrace his steps. But although it has been easy enough to go down, it is almost impossible to get back, for the surface of the inside of the pitcher is thickly covered with sharp bristles, all pointing downward.
Some flying insects may escape, but even these do not find it easy, as witness the fact that the plant often catches a large number of winged creatures. In the lower part of the Sarracenia pitcher a fluid is secreted, and it is into this that the creatures ultimately fall, and, of course, perish. How successful are the Sarracenias in their insect-catching may be gathered from the fact that pitchers have been discovered well nigh full of flies and other small creatures.
A PLANT WITH PRISON
WINDOWS
The California Darlingtonia seems to have been specially devised for the securing of winged creatures. The plant is most singular in appearance, and the upper part of the pitchers bear a remarkable resemblance to the head of a snake. Part of the hood and also the two protruding leaves are gaily colored in crimson. It should also be noted that the upper portion of the hood is adorned with transparent patches, like so many little windows. Now, the only opening into the pitcher of the Darlingtonia is quite a small hole on the under side of the hood. As in the case of the other pitcher plants, the orifice of this hole is freely supplied with honey, and this extends well into the interior of the receptacle.
Owing to the attraction of the little windows, which have been already mentioned, the flies do not attempt to get out of the hole to the extent which might be supposed. The light streaming through the transparent spaces seems to convince the insects that in that direction lies the path to freedom. At all times it is possible to see perhaps a dozen flies bobbing against the windows in a vain endeavor to escape. Finally, wearied to death by their hopeless endeavors to escape, the insects fall down into the lower part of the pitcher and become suffocated by the fluid it contains.