Vol. 89, Nos. 7 & 8, September & October 1978 169 INSECTS ASSOCIATED WITH A COLONY OF APHIDS, BRACHYCAUDUS CARDUI L., ON SCOTCH THISTLE, ONOPORDUM ACANTHIUM L., AT DUNNVILLE, ONTARIO^ W.W. Judd^ ABSTRACT: From July 4 to 14, 1976, insects associated with a colony of the aphid, Brachycaudus cardui, on thistle, Onopordum acanthium, at Dunnville, Ontario, were collected. They were in Coleoptera (4 families), Diptera (9 families) and Hymenoptera (4 families), including insects known as feeders on honeydew, predators and parasites of aphids and wasps that use aphids to provision their nests. In an account of the butterflies of Dunn Township, Ontario (Judd, 1963) it was pointed out that tlie Scotch Thistle, Onopordum acanthium L., grows in the township and is visited by butterflies. In the summer of 1976 a plant of this species was found infested with a colony of aphids in the south end of Lot 1, Concession IV of Dunn Township, Haldimand County on the north sliore of Lake Erie. Dunn Townsliip has recently been incorporated into the Town of Dunnville. The plant was growing in a ditch. Pressed flowers and leaves are included in the writer's herbarium (No. 805, August 9, 1976). During June of 1976 a colony of aphids was seen to be developing along the stem of the upper part of the plant and through tlie first two weeks of July other insects were actively visiting the colony. The aphid, ^rac/zvcawc/z/s cardui L., originally placed in the genus Aphis by Linnaeus, has been in-cluded, over the years, in other genera, Q.g.Anuraphis,Prunaphis{EdiSi\io^dXi<\ Ris Lambers, 1976). It has been reported by Patch (1938) as using several species in various families as food including thistles in the genus Cirsium and Onopordum acanthium L. From July 4 to 14, 1976, insects visiting the colony were collected by using an aspirator or an insect net or by clapping between the lid and jar of a cyanide jar. They were identified by the following staff members of the Bio-systematics Research Institute, Canada Agriculture, Ottawa: J.M. Campbell (Bryoporus), B. Cooper (CaUiphoridae), M. Ivanochko (Ichneumonidae, Formicidae), C.C. Loan (Diplazon), W.R. Mason (Braconidae), L. fVlasner (Sphecidae), J.F. McAlpine (Anthomyiidae, Muscidae, Otididae, Tephritidae), J. McNamara (Coleoptera), B.V. Peterson (Chloropidae), W.R. Richards (Brachycaudus cardui), J.R. Vockeroth (Ceratopogonidae, Dolichopodidae, Scatophagidae, Syrphidae). All specimens are deposited in the collection of the Department of Zoology, University of Western Ontario except one, Bracon tenuiceps, kept in the National Collection, Ottawa. Accepted for publication: April 12, 1978 Department of Zoology, University of Western Ontario, London, Ontario, Canada. ENT. NEWS, 89: 7 & 8: 169 -173, September & October 1978
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