Host Plant Specificity and Allozyme Variation in the Parthenogenetic Gall Wasp Diplolepis mayri and its Relatedness to D. rosae (Hymenoptera: Cynipidae)
The host plant affinities and allozyme variation of the gall wasp Dipioiepis mayri (Schlechtendal 1877) in S Sweden are investigated and comparisons to the parthenogenetic D. rosae (Linnaeus 1758) are made. 2 electrophoretically distinct types of D. mayri, both clearly separated from D. rosae, were detected; a N-type which parasitizes Rosa majalis and R. villosa, and a S' type confined to R. rubiginosa. The N-type, which consists of 3 slightly differentiated genotypes, appears to have colonized Sweden from Finland. The S-type is attacked by the parasitoid Orthopeima mediator (Thunberg 1822) (Ichneumonidae) and the inquiline Periclistus brandtii (Ratzeburg 1831) (Cynipidae). Both these species are common in the galls of D. rosae, but were not found in the galls of the N-type of D. mayri, which have another inquiline, P. caninae (Hartig 1840). Males are common in the S-type and at the most N-localities of the N-type. The systematic relationship between the 3 forms as indicated by the electrophoretic data differs from that implied by host plant specificity, parasitoids, and gall structure.