Evaluation of morphological and genetic variation in 3 Contarinia gall midges (Diptera: Cecidomyiidae) infesting Douglas-fir needles

Douglas-fir (Pseudotsuga menziesii) has three Cecidomyiidae midges (Contarinia constricta, C. cuniculator, and C. pseudotsugae) utilizing developing needles for larval galls.  In British Columbia, all three species can be found in the same tree, but each species supposedly utilizes a different portion of needles.  In Oregon and Mexico, only C. pseudotsugae is known.  Shipments of Oregon Christmas trees to Mexico are occasionally rejected due to the presence of one of the species not known to occur. Partly in response to this trade issue, we have undertaken to evaluate the status of the three needle midge species.  We have made collections at the type locality in British Columbia to compare against the descriptions and material from Oregon.  Morphological characters used to differentiate adults of the species include the male and female genitalia and proportions of palpal segments.  Larval characters include color, the shape of the ‘scraper’, and appearance and position of the gall.  The characters are subtle, and many of the larval characters overlap between species.  Problems in the original papers include mislabeled figures and illustrations of the species that do not match descriptions. We have acquired and examined types and some paratypes.  We will also examine a fragment of the mitochondrial gene CO1 that shows informative variation between other Contarinia species.  The CO1 fragment will be cloned using PCR primers developed for C. nasturtii, Swede midge, and a TaqMan fluorescent probe matching a sequence within the CO1 fragment conserved between 5 Contarinia species previously investigated.