Read Ebook: The Ohio naturalist Vol. 1 No. 8 June 1901 by Ohio State University Biological Club

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Entered at the Post Office at Columbus, Ohio, as second class matter.

The Ohio Naturalist

PUBLISHED BY

THE BIOLOGICAL CLUB OF THE OHIO STATE UNIVERSITY

Vol. 1. JUNE, 1901 No. 8

A STUDY IN VARIATION ON THE WING OF THE HONEY BEE.

F. L. LANDACRE.

While working on the Honey Bee in the laboratory at the University it was observed that the number of hooks connecting the posterior wing with the anterior was not constant.

The query at once arose as to the amount of variation there might be between different bees in the same hive and also between different hives. Out of this grew a somewhat practical problem as to whether the increase in number of hooks was associated with a decrease in the size of the wing, or whether the increase in number of hooks also implied an increase in size of wing.

The wings of the bee are undoubtedly more efficient for being closely attached to each other. The life of the workers is so short, being only about three weeks, and their activity so great that any increase in efficiency, especially in the organs of flight, must have a very direct influence on the welfare of the whole swarm. So far as the well being of the swarm depends upon nutritive processes the efficiency of the hive is equal to the average efficiency of the workers. Now, if the increase in number of hooks and the consequent, firmer attachment of the wings is compensated for by a smaller wing, there is much less opportunity for the operation of natural selection on the individual bees than if the greater number of hooks is always associated with a broader or longer wing.

This selective process might occur either in the hive or between hives. If it occurs in the hive it would increase the efficiency of the hive somewhat; but if it occurs between hives it finally means the elimination of the weaker hive and the consequent increased efficiency of the species.

In order to find out the real conditions, one of the students, Mr. J. N. Frank, took twenty-five workers from each of four hives and counted the number of hooks on each wing, right and left, and also measured the width of the anterior and posterior wings on each side, The width only was taken on account of the difficulty in finding a good point at the base of the wing from which to measure the length. The results are so uniform that the width probably gives sufficient data from which to draw conclusions.

Of the four hives studied, numbers one and two were very weak. Number three was a strong hive which made forty pounds of extra honey in the summer of 1900. Number four was weaker than number three and made only ten pounds of extra honey.

The complete measurements are too long to give in detail, and the averages only will be offered here.

AVERAGES OF TWENTY-FIVE MEASUREMENTS FOR EACH HIVE TAKEN WITH AN EYE-PIECE MICROMETER, EXPRESSED IN MM.

HIVE NUMBER ONE.

HIVE NUMBER TWO.

HIVE NUMBER THREE.

HIVE NUMBER FOUR.

As to the first query concerning the individual variations in a single hive the complete table shows that No. 1 varies from 18-21 hooks, No. 2 from 17-21, No. 3 from 18-23 and No. 4 from 17-21. The right wing is taken as the standard, and the most active hive, No. 3. shows the greatest individual variation. One bee in this hive had only sixteen hooks, the remaining three being straight spines, showing how the hooks have been modified from ordinary hairs. This reversion occurred on three separate wings, in No. 2 one hook on each wing being straight.

As to the relation between the number of hooks and the width of the wing the averages are very definite. Taking hives number one and two from the same apiary, it will be seen that the increase in number of hooks goes with the increase in width of wing. The same relation is shown by hives numbers three and four from another apiary in the case of the posterior portion of the right wing and in both anterior and posterior portions of left wing.

The results are not conclusive as to the relative efficiency of different hives because there are so many conditions entering into the production of large quantities of honey. The number of bees, the care during the winter, the age of the queen, the number of swarms produced, and several other factors would have to be taken into consideration.

The differences in the right and left wings in the bees of the same hive is marked. The right wing has the larger number of hooks, but the left wing is the broader. In hive number one the average number of hooks in the right wing is 21.3, left 20.9; but the anterior wing on the right side is 4.21 mm., while the left anterior wing is 4.28; that is, there is a compensation for the reduced number of hooks in the increased width of the wing. This is true of the first three hives. In the fourth hive there is a slight advantage in favor of the right wing.

The following general conclusions may be drawn from these measurements:

There is a variation in the number of hooks in a given hive ranging between 17 and 23.

The difference in the number of hooks in the right and left wing is compensated for in a given hive by the increased size of the wing. The right and left wings are in physiological equilibrium.

In different hives the increase in the number of hooks is accompanied by an increase in width of wing; that is, the variation is emphasized so that selection would work much more effectively; while in the individual, where--if selection operated on account of this variation--it would have to be between different wings of the same bee, the variation is eliminated.

TWELVE PLANTS ADDITIONAL TO THE OHIO LIST.

W. A. KELLERMAN.

The species named below have not heretofore been recorded as a part of the Ohio flora. The first collector and locality are given for each of the listed species. The serial number prefixed to each name indicates where in the Fourth State Catalogue the species should be inserted.

THE FOOD HABITS OF SOME APHROPHORA LARVAE.

E. D. BALL.

The larvae of all the American species of the Family Cercopidae as far as known envelope themselves in a frothy mass. Contrary to popular opinion and to most of the published accounts this froth does not issue as bubbles from the body of the insect, but is made by pushing the tip of the abdomen up out of the froth and grasping, with the anal appendages, a bubble of air and bringing it down and releasing it within a liquid film. This liquid film is simply the excretion from the alimentary canal of the sap which is imbibed by these insects in large quantities. This copious liquid excretion is a common occurrence in other families of the Homoptera. In the Plant Lice it gathers in drops and is called "Honey Dew." The Leaf Hoppers and Tree Hoppers expel a clear liquid with some force. In some species this is in sufficient amount so that when the insects are numerous the foliage may drip, producing the "Weeping trees" of the Southern States.

The larvae were found in these clumps from late in May until the first week in July in the foot hills, and higher up in the mountains they were just beginning to emerge July 20th. When ready to emerge they climb up a stem during the night far enough to free themselves from the froth and as soon as the sun strikes then in the morning they burst their pupal skins and an hour later they are ready to fly up to the pine trees where their color admirably protects them.

It will be interesting to discover whether a similar food habit occurs in any of the Eastern members of the genus or whether this is peculiar to the western species. It seems possible that original pine-inhabiting species finding themselves unable to maintain their froth masses in their exposed positions on pine branches in such a dry atmosphere were compelled to seek moister conditions such as are afforded by the shade and contact with the earth under these bushy plants.

Fig. 2. Pupa of above. 2a--Side view of head of pupa.

FOOTNOTES:

For a detailed account of this process see Prof. Morse's article "A Bubble-blowing Insect." Pop. Sc. Monthly, May, 1900.

ROBERT F. GRIGGS.

Most of the manuals are entirely silent regarding the vernation of the Willows. Sargent describes their leaves as "variously folded in the bud" and under different species gives them as: involute, revolute, convolute, and even conduplicate in the bud. The fact that he gives two species, closely related and difficult to distinguish, at the time the buds open , as having involute and revolute vernations, led me to take up the matter to see if a key for their identification from bud characters, could be constructed.

Not only did I find that they were not involute and revolute respectively; but that they were neither involute nor revolute, but both imbricate. On examining other species the same thing was found. The only exceptions to the true imbricate vernation found are represented in figures 3 and 4. The section Purpureae, on account of its tendency to have opposite rather than alternate leaves, often forms such decussate buds as are shown in figure 3. In Salix incana Schrenk, a species whose leaves at maturity have revolute margins, the leaves have a greater or less tendency to roll backwards in the bud. The most extreme case found is shown in figure 4. Others from the same twig could be shown where the leaves show only the slightest tendency to be revolute. If we may consider that this backward turning is merely a character of the mature leaf manifesting itself in the bud it is evident that there is here no revolute vernation but that it is really imbricate.

The other buds examined vary from the form represented in figure 1 where the whole interior of the bud is taken up with the closely packed leaves, to that shown in figure 2 where there are a few leaves with a great deal of wool.

Species like Salix fragilis L. whose leaves are glabrous when they unfold have buds like the former while species like Salix discolor Muhl., with leaves excessively wooly when they unfold, are like the latter. As there are all intergradations between these two kinds of leaves, there is naturally a series of buds between these two as extremes. While further investigation is necessary before we would be warranted in declaring that the vernation of the whole genus is imbricate; yet the fact that specimens of thirty-four species and varieties, taken from thirteen of the nineteen sections given by Andersson in DeCandolle's prodromus, have their leaves imbricated in the buds would seem to establish a presumption in favor of such a view.

The buds examined were soaked in 70% alcohol and free-hand sections cut and mounted in balsam. On account of scarcity of material, the buds of several species were not sectioned but dissected on the growing plant. Such are marked with an asterisk . As far as possible living material was taken, mostly from native plants. Those species not native were studied from specimens growing in the University Botanic Garden. In a few cases dried specimens were resorted to. About one hundred and twenty-five plants belonging to the following species and varieties were examined.

EXPLANATION OF THE FIGURES.--Fig. 1. Salix fragilis L. Bausch and Lomb obj. 2/3 oc. 2.

Fig. 2. S. discolor Muhl. B. & L. obj. 2/3 oc. 2.

Fig. 3. S. purpurea L. B. & L. obj. 2/3 oc. 2.

Fig. 4. S. incana Schrenk. B. & L. obj. 2/3 oc. 1.

The figures were drawn with an abbe camera lucida and reduced to 2/5 of their original size.

FOOTNOTES:

Sargent: Silva of North America 9: 95.

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