Ampeloglypter sesostris

Ampeloglypter ampelopsis

Ampeloglypter sesostris Lec

About ten years ago this insect was made the subject of an investigation in Ohio, conducted by F. M. Webster, and the results were published as Bulletin ii6 of the Ohio Experiment Station. The bulletin gives the more essential facts in regard to the gall-maker and its habits, but since the publication of that paper a few additional points relative to the species have been observed in West Virginia. These observations, together with those already published, give us a fairly complete knowledge of the insect as it occurs in this section of the United States. Webster collected galls from grapecanes in June and kept them until the larvae which inhabited them transformed to beetles in August and September, thus showing that the adult stage is reached in late summer instead of in the spring;, as had been supposed previously. I was unable to duplicate this breeding work satisfactorily on account of the extent to which my specimens were parasitized. On the other hand, I watched the female on several occasions while she was engaged in egg-laying, an operation which I believe has not been described heretofore. Most of my observations on this species were made at French creek, W. Va., in the summer of 1905. where, at that time, the beetles were very abundant. Since 1905 but few specimens have been seen in that locality and examples of their work have been correspondingly scarce. 

The species was described by LeConte in 1876, from specimens collected in Missouri. Since that time it has been reported from Minnesota, Ohio, Pennsylvania and other eastern, south-eastern and mid-western states.

The injury done to the vines by this insect is in the shape of gall-like growths that begin to develop on the new canes early in the summer. These galls are abrupt swellings of cane to something like twice its normal diameter, the enlargements being an inch or an inch and a half in length. The swelling is about uniform around the cane except that on one side there is a deep longitudinal scar from a half to three-fourths of an inch in length. This scar comes from a wound made by the female beetle in preparing a place to lay her egg. The gall is almost invariably located just above a joint of the cane. I examined several hundred of the galls and found only one in which the lower end was as much as an inch above a joint. The one exception was that of a gall located three- fourths of an inch below a joint. The cane on which this gall was found w^as being trained in a horizontal position and the gall occurred just below instead of just above the joint, evidently through an error on the part of the beetle that made the wound which caused the gall to form. Occasionally a single cane will bear four or five galls, and on one cane I found nine. Strange to say, the female nearly always selects the joints of the young cane beyond the last or outer bunch of fruit for her points of attack. Consequently, if an infested cane is bearing a bunch of fruit at each of the three joints nearest its base the galls will not appear at these joints, but the first one will be found not nearer to the base of the cane than just above the fourth joint. In several cases where canes were bearing but two bunches of fruit, galls were found at the third joint. This peculiarity was noticed so often that there seems little doubt that the female rejects the fruiting joints as being unsuitable places for her eggs to be deposited. Just why she should discriminate against the fruiting joints is not very clear.

The swelling of the cane at the point of injury begins soon after the wound is made, but the gall does not reach full size until six or eight weeks later. On vines of varieties that produce dark-colored fruit the bark and wood about the wound soon takes on a reddish-purple color. This discoloration does not occur on varieties that bear white or green fruit.

The presence of the galls appear to have but little effect on the growth and vigor of the cane. Occasionallv a cane that has no support will be broken by the wind or by its weight of leaves at the point of injury. In tying up the canes after pruning in the spring they will sometimes break more readily at the galls than elsewhere. In pruning vines affected with the galls this should be borne in mind and the canes on which no galls are found should, when possible, be preserved for fruiting.

Ampeloglypter ater LeConte

This insect is not often mentioned in entomological literature, probably for the reason that in the past it seems to have confined its attacks chiefly to the plant known as Virginia Creeper or Five-leaved Ivy, Ampelopsis quinquefolia, and has seemed, therefore, of but little economic importance. In this state it appears now to have developed a preference for the grape. In several localities I have seen grapevines presenting a ragged appearance on account of the dead tips resulting from the insect's attacks, but I have never been able to find either the beetle or evidences of its work on Ampelopsis.

The species cannot now be regarded as a pest of very serious consequence, except in rare instances, but, as it has several times attracted attention as an enemy of the grape in this state during recent years, and as heretofore but little has been known / in regard to its habits, it seems worth while to publish the following notes.

The distribution of the species seems to be quite general throughout the eastern and mid-western sections of the U. S. In 1862 Mr. C. V. Riley, in his First Report on the Noxious Insects of Missouri, mentioned it as forming galls on the common creeper. At about the same time Mr. Benj. D. Walsh had specimens of the insect in his collection in Illinois, marked "Madarus ampelopsis." It was not until the year 1876 that a description of the beetle was published. In that year Dr. John h. LeConte described it in his work on the Rhynchophora of America, and gave to it the name which it still bears. LeConte gives its geographical distribution as "Southern and Western States." Since the description was published the species has received but infrequent and brief notice, but has been recorded as occurring in several states from Missouri to Pennsylvania. 

It seems a little strange that in nearly every case where it has been mentioned it has been referred to as a gall-maker on Ampelopsis. As already stated, I have not found it on Ampelopsis in West Virginia, although this plant grows profusely in the localities where the insect has ben observed in greatest abundance. Ampelopsis is nearly related to the grape, however, and if this insect has now given up a once favorite iood for another which it finds more to its liking the case is by no means unique in the history of insect behavior. In 1895 Dr. F. H. Chittenden remarked (Insect Life, Vol. VII, p. 387:) "Species which are known to aflfect Ampelopsis and other genera of the vine family will be found in time on the grape. Of such is Ampeloglypter ater." It now seems that this prediction has come true, even to the extent of the old food plant being abandoned, temporarily at least. The appellation "gall-maker" does not apply to the species as I have found it affecting the grape. The term "girdler," however, is entirely applicable. When the female lays her egg she carries out an elaborate program, one act of which is to girdle the cane below the point where the egg is inserted. The proceeding is an interesting one and is described in detail further along in this publication.

The larva is a footless grub about one-fourth of an inch in length. Like the larva of the gall-maker, it is white with a light-brown head. It feeds in the heart of the cane, eating out a burrow that extends only between the two joints on either side of the place where the egg is laid. The larval stage covers a period of something over a month. In one case I got an exact record of its duration which was thirty-four days. 

The cane in which the larva feeds dies back to the first joint below the egg-chamber and drops from the vine in about six or eight weeks after the eggs are deposited. The larva changes to a pupa soon after the dead section of the cane drops

The grapecane gall-maker and the grapecane girdler