PROCEEDINGS 1917 85 



NOTES ON THE BIOLOGY OF LYGUS PRATENSIS LINN., 



IN ISIOVA SCOTIA. 



By W. H. Brittain and L. G. Saunders. 



THIS INSECT has a wider range and is more nearly omnivorous than any of our 

 common insect pests. It is a native of Europe where it is common and widespread 

 and is also well known over the greater part of North America, two varieties 

 L. pratensis var. oblineatus Say and L. pratensis var.rubidus F night, being recognized. 

 The number of plants upon which it is reported to feed is legion and the loss that it oc- 

 casions throughout its range must aggregate an enormous sum. 



A bibliography that would include all references to the insect and its work would 

 cover many pages, but detailed knowledge of the life history of the insect appears for 

 the most part to be fragmentary. Haseman (6) appears to have been the only one who 

 states definitely that he has reared the insect through from the egg to the adult stage. 

 We are chiefly interested in this insect in its relation to the apple and pear and in this 

 connection a def nite knowledge of the life history of the insect and of its food plants, 

 particularly the nymphal food plants, is of obvious importance. 



Accordingly in the spring of 1917 we began a study of the life history and habits of 

 the insect, the work being conducted from the Kentville laboratory. These studies are 

 as yet incomplete, but it is our intention to continue them in future seasons. 



HIBERNATION 



Our observations on the question of hibernation coincide with those of most other 

 workers viz. that the insects winter in the adult stage. Though considerable numbers 

 pass the winter in this way, they are evidently able to conceal themselves quite ef- 

 fectively, for they are by no means easy to discover. We have found small numbers be- 

 neath stones lying in a pile along a fence and overgrown with weeds, others beneath the 

 remains of cabbage plants in a former cabbage patch and a few more in similar locations, 

 but never in large numbers. Both males and females hibernate, not females alone as 

 some workers have said. Dissections of the flrst females taken in the spring revealed no 

 developed eggs. 



FOOD PLANTS OF HIBERNATED ADULTS AND OF FIRST BROOD 



NYMPHS. 



When the adults come out of their winter quarters, they are often found, sometimes 

 in considerable numbers, resting upon apple and pear buds in orchards, particularly 

 on bright sunny days, and will readily take flight when disturbed. A correspondent 

 writes that they were present in his young orchard in immense numbers on April 26th 

 and that he was able to drive them before him "like a flock of sheep." It is probably 

 unusual to find them in such large numbers in apple orchards. We have seldom noticed 

 any great harm resulting from their presence in the orchard at this time though they 

 may do damage by withdrawing the sap from the buds and causing them to wither and 

 die. They may also be found in more or less abundance on early flowering plants, such 

 as willows. They remain on these plants until more succulent herbage has developed. 



About Kentville the favorite early spring food plant was found to be sheep sorrel 

 (Rumex acetosella). They could be observed at almost any time feeding freely upon 

 this plant and indeed were not found in numbers on any other. Most of the hibernated 

 adults had laid their eggs and perished by the first week in July, when the adults of the 

 spring brood began to appear. 



