An Elementary Study of Insects Part 6

CHAPTER XV

THE PLANT-LOUSE

For this chapter any common species of plant-louse may be used. If the study is made in the spring the louse on rose, apple, clover, wheat or any other crop may be used. If the study is made in the fall the species on turnips, corn or other plant or crop may be selected. The different species vary greatly but for these studies any available species will be satisfactory.

The plant-louse or aphis is a sap-sucking insect which feeds and multiplies rapidly often seriously injuring crops. The loss of sap together with the poisoning effect of the bite causes the weakening of the plant or leaf with its ultimate death if feeding continues. The greatest damage is usually done during cold springs or during a cool rainy period. This prevents the enemies of the louse from increasing and attacking it while the weather may not be too severe to prevent the louse from working. Under favorable climatic conditions the natural enemies of the louse as a rule are able to hold it in check. The princ.i.p.al enemies of the louse are certain small insect feeding birds, lady-beetles, syrphid-flies, lace-wings and tiny wasp parasites. The beneficial work of the lady-beetles is discussed in an earlier chapter.

The birds and lady-beetles devour them bodily, the larvae of the lace-wings and syrphid-flies extract their blood while the wasps live as internal parasites.

In the lat.i.tude of Missouri the plant-lice as a rule live thru the winter in the form of a fertile egg attached to the twigs of trees and shrubs. The winter egg is produced by a true female plant-louse. As a rule there is only one generation of true males and females produced each year. This brood develops late in the fall to produce the fertilized winter eggs. In the spring these eggs hatch and the tiny nymphs begin to extract sap. On maturing they begin to give birth to young lice. Throughout the summer this method of reproduction continues.

These summer forms are known as the stem mothers or agamic females.

These are not true females for they produce living young in place of eggs and during the summer no male lice are produced at all. This is nature's way of increasing the race of plant-lice rapidly. Late in the fall again a brood of true males and females is produced. During the summer the plant-lice increase more rapidly than any other type of insect.

[Ill.u.s.tration: Black winter eggs of Aphis showing how they are deposited in ma.s.ses on twigs of apple. (After U. S. Dept. Agri.)]

Plant-lice vary in size, color and general appearance. Many are green while some are red or black or covered with a cottony secretion.

OBSERVATIONS AND FIELD STUDIES

Plant some melon, radish or other seeds in fertile soil in pots for use in this study. When lice appear on crops in the garden or field, collect a leaf with a few on it and carefully transfer them to the leaves on your potted plants. Watch the lice feed and increase from day to day. A reading lens or a magnifying gla.s.s will be helpful as plant-lice are very small. How do they move about? Can you count their legs? How many have they? Can you see their eyes and feelers? When feeding observe how the beak is pressed against the leaf. Disturb one while it is feeding and see it attempt to loosen its mouth parts.

[Ill.u.s.tration: Common apple aphis showing a winged and wingless agamic summer forms at a and c, one with wing pads formed at b, and a recently born young at d. (After U. S. Dept. Agri.)]

In the garden examine and see if you can find lady-beetles or other parasites attacking the lice. Collect some of the enemies of the lice for your collection. Make a gallon of tobacco tea by soaking one pound of tobacco stems or waste tobacco in one gallon of water for a day or use one ounce of forty per cent nicotine sulphate in three gallons of soap suds and spray or sprinkle infested bushes or vegetables with it.

In an hour examine and see what effect it has had on the plant-lice.

Nicotine is the most effective chemical for killing plant-lice. Do any of the lice develop wings? If so, how many? Wings develop on some of the lice at times when a plant or crop becomes too heavily infested by them.

This enables some of the lice to spread to new food plants before old plants are completely destroyed and the colony of lice starved.

[Ill.u.s.tration: Wooly apple aphis, showing how they cl.u.s.ter in ma.s.ses on limbs and secrete the white, wooly protection over their bodies.]

Make a careful enlarged drawing of a winged plant-louse and a wingless one showing legs, feelers, beak, honey dew tubes on back and body segmentation. If ants are seen to attend the lice observe them carefully and describe their work. The ants feed on a sweet honey dew excretion discharged by the lice.

CHAPTER XVI

THE HONEY BEE

"_Simple and sweet is their food; they eat no flesh of the living._"

--VON KUEBEL.

One can hardly believe that this small, ever busy creature each year gathers many million dollars worth of products for man in this country alone to say nothing of its inestimable value on the farm and especially in the orchard, where it a.s.sists in carrying pollen from blossom to blossom. It is of far greater value to man as a carrier of pollen than it is as a honey gatherer and yet under especially favorable conditions in one year a strong colony may produce between twenty-five and thirty dollars worth of honey.

[Ill.u.s.tration: Worker, queen and drone honey bees; all about natural size. (After Phillips, U. S. Dept. of Agri.)]

The general habits of the bee are fairly well known by all. They live in colonies consisting largely of workers, one female or queen and males or drones. Whenever the number of workers becomes sufficiently large to warrant a division of the colony, a young queen is reared by the workers and just before she matures, the old queen leaves with about half of the workers to establish a new colony. This division of the colony is called swarming. If a hive, box or other acceptable home is not provided soon after the swarm comes out and cl.u.s.ters, it may fly to the woods and establishes itself in a hollow tree where the regular work of honey gathering is continued. This accounts for so many bee-trees in the woods. The bee has been handled by man for ages, but it readily becomes wild when allowed to escape to the woods.

[Ill.u.s.tration: Stages of development of honey bee; a, egg; b, young grub; c, full-fed grub; d, pupa; all enlarged. (After Phillips, U. S.

Dept. Agri.)]

The bee colony offers one of the best examples to show what can be accomplished by united effort where harmony prevails. Certain of the workers gather honey, others are nurses for the queen and young brood in the hive, others guard the hive and repel intruders, and others care for the hive by mending breaks and providing new comb as it is needed. Each knows its work and goes about it without interfering with the work of others. It is one huge a.s.semblage of individuals under one roof where harmony and industry prevail.

Throughout the long, hot summer days the workers are busy from daylight until dark gathering nectar, while at night they force currents of air thru the hive to evaporate the excess water from the nectar. When flowers are not available near the hive they simply fly until they find them, be it one, two or more miles. As long as they are able to gather honey they continue to do so and when they give out they drop in the field and are forgotten, others rushing to take their place. Often when winter is approaching and the store of honey is low the less vigorous ones are cast out from the hive and left to die. If man could learn a few of the lessons which the bee teaches, he would be a better, a more useful and a wiser addition to society.

OBSERVATIONS AND STUDIES

[Ill.u.s.tration: Two colonies of bees poorly cared for. Note box hives, crowding, lack of shade, and high weeds. It is a crime to treat bees this way.]

Go into the fields and study the work of the bee. Follow it from flower to flower. See if it visits different kinds of flowers or if it gathers its whole load of honey from one kind. Make a list of all the blossoms you find bees visiting. Does the bee move slowly from flower to flower?

Can you see it thrust its tongue into the flower? How long does it stay on one blossom? Does it visit red clover? Pull a red clover blossom apart and compare the depth of the blossom with the length of the honey bee's tongue, and determine the reason why it does not visit red clover. The b.u.mble-bee has a much longer tongue so it can get the nectar from red clover blossoms. Without the b.u.mble-bee clover seed could not be successfully grown. Can you see small b.a.l.l.s of yellow pollen on the hind legs of the bee? The pollen is collected from blossoms and is pasted on to the outside of the hind legs in the pollen basket. When the bee returns to the hive, it stores the small b.a.l.l.s of pollen in the cells of the comb for use later in the preparation of bee-bread. When the bee is disturbed in the field does it fly away or will it sting?

When it stings does it always lose its sting? What makes the sting of the bee poisonous? Examine the wings of bees in the field and note how they are torn from continued work of gathering honey. The older ones often lose so much of their wings, that they can no longer carry loads of honey. Where is the honey carried and how is it placed in the honey cells in the hive?

[Ill.u.s.tration: A strong colony of bees properly housed and shaded. This colony in a very unfavorable season stored about 50 pounds of surplus honey.]

Go now to a hive and study the bees as they go and come. Do those returning fly as fast as those which leave? Why not? When they return do they come direct to the mouth of the hive? Do those which leave fly direct from the hive or circle about first? Can you detect guards which move about at the entrance of the hive? What happens when a fly or other insect alights near the opening? Will the bees sting when you disturb them about the hive? If possible study the colony inside the hive. To do this you will need smoke to subdue the guards and a veil to protect the face. Can you find the queen? Is she larger than the workers? Examine for honey-comb, bee-bread, worker brood, queen cells and drone cells. If possible study the actions of a colony while swarming.

Write a brief report of what you can learn of the life, work and habits of the honey bee.

"_Happy insect, what can be In happiness compared to thee?

Fed with nourishment divine, The dewy morning's gentle wine!_

"_Nature waits upon thee still, And thy verdant cup does fill; 'Tis filled wherever thou doest tread Nature's self thy Ganymede._

"_Thou doest drink and dance and sing, Happier than the happiest king!

All the fields which thou doest see, All the plants belong to thee, All the summer hours produce, Fertile made with early juice, Man for thee does sow and plough, Farmer he, and landlord thou._"

--From THE GREEK OF ANACREON.

CHAPTER XVII

THE ANT

The ants are closely related to the bees and are similar to them in many respects. They live in colonies consisting of workers, drones, and a queen. The males or drones appear at swarming time and the workers are divided into various castes--warriors, guards, nurses, etc. Those families of ants, however, which seem to have what approaches real intelligence, far outstrip the bees in many respects. In some cases ants seem to be able to plan and carry out lines of work very much the same as man does. The various stages of human intelligence or races of men from the savage to the intelligent man are in a way similar to the various races of ants. There are ants which live as hunters, others which live as shepherds and still others more highly developed which grow crops either in or near the nest as is the case with the fungus growing ants. This striking similarity between the development of ants and man offers ground for much speculation.