Part 35

The strange ways of life of hormophis hamamelidid—which goes through fourteen different life stages in the course of a year’s lifetime—are being studied by scientists in the hope of isolating a mysterious something which may open the door of some of the greatest paradoxes of biology.

The insect is an aphis which causes galls, growths comparable to animal cancers, on witch hazel leaves. These growths result when the aphis injects into the leaf by means of a microscopic apparatus like a hypodermic needle an infinitesimally minute amount of an unidentified substance. The gall grows around and over the insect. It becomes the tiny creature’s home.

The substance completely changes the nature of the plant cells. They normally would become leaf cells, highly specialized to fit into leaf growth. Now they become gall cells. Something similar happens in cancer, except that the new cell growth, having escaped from the government of the animal body, is entirely uncontrolled. The gall cells, however, still remain under some sort of control. They always form galls and they do not kill the leaf, which is necessary for their existence.

Marvelous is the life story of the aphis itself. The sequence starts with a “stem mother”, a newly hatched female. She injects the substance into the leaf and the house builds itself around her. Inside this house she passes through four stages. Her structure changes completely four times. That is, she becomes in a sense four different animals, one after another. In the fourth stage she gives birth to from fifty to a hundred living young.

Each of these young, in turn, goes through four stages. In the last of these they have wings. The winged insects crawl out through a hole in the bottom of the gall. Each produces from ten to twenty young on the bottom of the leaf. Each of the young, in turn, goes through five stages. During the last they are both males and females. This is the only time the male makes its appearance in the life cycle. All the other births are by parthogenesis.

Each of the females lays eggs in the winter on the witch hazel. The buds are destined to become leaves in the early Spring. The eggs hatch a few days before the leaves appear. Each of the newly hatched aphids—all females—injects some of the house-building material into the leaf upon which she finds herself. She becomes a new “stem mother” and the strange process starts all over again.

The rapid reproduction rate might well be overwhelming to the witch hazels, and consequently suicidal for the insects, except for certain enemies which keep down the numbers of the “lice”. Such tiny forms of life as larval lacewings are able to crawl through the hole in the bottom of the gall and feed on the occupants during their various stages.

University of Virginia biologists who have been giving particular attention to the aphis are interested primarily in the substance injected into the leaves. It must be one of the most potent growth factors in nature. The amount any one aphid is able to inject is indescribably minute, even though some of them make as many as 50 separate injections. The material causes the leaf cells to become larger and to multiply much more rapidly until a “house” many times the size of the aphis is complete in a few days. The structure is perfect, even including a “picket fence” of tiny hairs around its base to keep out invaders.

The substance exists in such minute amounts that thus far it has been impossible to isolate it in anything approaching a pure form. The Virginia biologists have set themselves a task requiring infinite patience over many years—tracing the increase of the amount in the salivary glands of each individual through each of its fourteen lives, and also through the eggs with which the strange life cycle starts.

The present clues indicate that the substance is a filterable virus—tiniest of living things compared with which the pinhead-sized aphis is like a whale compared to a fly.

Shyness Characteristic of Giant Rats

Biggest of the extant true rats is the giant rat of Liberia. It is two feet or more in length and is similar in appearance to the Norway rat which infests houses all over the world. Fortunately this creature never has invaded the homes of men. It is a shy animal of the cane brakes.

Nocturnal Potto

One of the weirdest of living mammals is the potto—“ghost monkey”, of West African jungles. It is about the size of a squirrel, with soft, yellow fur and protruding yellow eyes which shine like malevolent witch lights in the darkness of the jungle nights. The potto is a nocturnal animal of the tree tops. Its weird, whimpering cries are believed by natives to be the voices of evil spirits. The little creature is an aberrant member of the family of lemurs, ancient offshoots of the same family from which sprang the monkeys and great apes.

Where Trees are Square

A few miles north of the Panama Canal Zone is “the valley of square trees.” This is the only known place in the world where trees have rectangular trunks. They are members of the cottonwood family. Saplings of these trees now are being grown at the University of Florida to find out if they retain their squareness in a different environment. It is believed, however, that the shape is probably due to some unknown but purely local condition. That the cause is deep-seated is indicated by the fact that the tree rings, each representing a year’s growth, also are square.

The Lamp That is a Beetle

The most brilliant animal luminescence known is that of the carbuncle beetles of Puerto Rico. They emit a light so brilliant that one or two inside an inverted tumbler illuminate a room of moderate size so that one can read a newspaper at night. Fields are illuminated brilliantly every night by these beetles, flying about a foot above the ground. The light is not intermittent, and seems nearly continuous. It varies from yellow to green for different species; occasionally it is yellowish-red.

Rainstorms of Worms

Rains of worms often have been reported. After a summer shower surfaces of puddles sometimes will be found covered with countless thread worms or nematodes. These worms have just come out of the bodies of water beetles and other insects, where they have developed as parasites. Before the shower the insects were dormant. These little worms in farm watering troughs led to the long-held belief that horsehairs sometimes changed into worms.

This does not, however, explain the following report in the Levant Times, an English newspaper published in Constantinople, of August 6, 1872:

“A letter from Bucharest reports a curious atmospheric phenomenon which happened there on the 25th ult. a quarter past nine in the evening. During the day the heat had been stifling and the sky was cloudless. In the evening everybody went out walking and the gardens were crowded. The ladies were mostly dressed in white, low-necked robes.

“Toward nine o’clock a small cloud appeared on the horizon and a quarter of an hour afterwards rain began to fall which, to the horror of everybody was found to consist of black worms the size of ordinary flies. All the streets of Bucharest were strewn with these curious animals.”

The Icy Arctic Wonderland

Abundant and fantastic are the creatures of the shallow Arctic sea bottom. All are invertebrates—worms, sea anemones and a host of other creatures—most of whom spend their lives buried in the mud.

Some of the creatures and their curious ways of life:

Ribbon worms which, when washed ashore, literally tie themselves in knots, curl up in balls, and secrete bags of mucous around themselves.

Bright green spoon worms about three inches long. These formerly were eaten by Eskimos.