Hymenoptera Reared from the Mossy Rose Gall Caused by Diplolepis rosae (L.) (Hymenoptera: Cynipidae)

Abstract

On January 10, 1958 a collection of 20 galls was made from a rose bush in an abandoned brickyard bounded by Cheapside, Taylor, Victoria and Adelaide Streets at London, Ontario. This was the same site in which collections of galls were made from goldenrod and willow by Judd (1953, 1958). Collections of flowers and leaves from the rose bush were made later in the year on June 20 and fruits were collected on September 14. From examination of these the bush was identified as Rosa canina L. by Dr. F. H. Montgomery, Department of Botany, Ontario Agricultural College, Guelph, who retained specimens of the plant for the herbarium of that institution. Specimens are also retained in the writer's herbarium (sheets 603, 604). By using keys in Felt (1940) the galls were identified as mossy rose galls or rose bedeguars caused by the cynipid wasp Diplolepis rosae (L.). The galls were roughly oval and were clothed with a furry covering of flexible filaments, thus resembling galls of this species figured by Connold (1902) and Felt (1940). The 20 galls ranged in size from l¼ in. × 1¼in. to 3 in. × 2½ in. Connold (1902) records the average dimensions of a mature gall to be 35 mm. and Felt (1940) reports diameters up to four inches. Callan (1944), Connold (1902) and Muesebecli et al, (1951) report that this gall has been introduced from Europe into North America and occurs habiyually on the dog-rose, Rosa canina L., a shrub which itself has been introduced into North America from Europe (Fernald, 1950).