INSECTS AND OTHER ARTHROPODS FROM YEAR-OLD GALLS CAUSED BY GNORIMOSCHEMA GALLAESOLIDAGINIS RILEY (LEPIDOPTERA: GELECHIIDAE) ON GOLDENROD

Abstract

Five hundred galls caused by Gnorimoschema gallaesolidaginis Riley on Solidago canadensis in Dunn Township, Haldimand Co., Ontario, were collected from June 30 to August 28, 1963. They had formed in 1962 and remained intact over winter into 1963. They were split open and insects and other arthropods inhabiting them were collected. Two hundred and thirty-two (46%) of the galls contained remains of the insect which caused them. Two hundred and twenty-two (44%) of the galls contained evidence of occupancy by organisms other than those which caused the galls or by parasites of the organisms. Spiders, including three identified species, used 21% of the galls as shelters and as sites for web-spinning or egg-laying, Millipeds and springtails were found in a few galls. A thrips, Elaphrothrips armatus, formed breeding colonies in 18% of the galls, and two other thrips occurred in a few galls. Damsel bugs, lace-wing flies, and beetles of the families Coccinellidae, Anthicidae, and Mordellidae inhabited a few galls. One gall was stocked with small caterpillars, evidently collected by a wasp. One fungus-gnat was found in a gall. Two wasps of the families Vespidae and Sphecidae and one bee of the family Colletidae, all three of which habitually nest in plant stems, were found in three galls. Four species of ants used several galls as sites for rearing young.