XIV International Entomophagous Insects Workshop: June 11–15, 2006, Newark, Delaware

Abstract

s are listed in alphabetical order by the last name of the senior author. Parasitoids of Myzus persicae and Aulacorthum solani on pepper crops in British Columbia Susanna Acheampong, David R. Gillespie and Don Quiring Pacific agri-Food Research Centre (Agassiz); 6947 #7 Highway; P. O. Box 1000; Agassiz, BC V0M 1A0; Canada, acheampongs@agr.gc.ca A survey of parasitoids of three clones of Myzus persicae (green peach aphid) and a clone of Aulacorthum solani (foxglove) on peppers in the lower Fraser valley of British Columbia, Canada from April – August 2005 revealed the presence of nine primary parasitoids. Aphidius matricariae was the dominant primary parasitoid species in all months, at all locations, and on all clones. Appearance of parasitoid species varied among parasitoid genera with some parasitoids occurring earlier in the season and others late in the season. Generally sex ratios were male-biased at the beginning of the season but as the season progressed, there was a shift towards a female-biased sex ratio. Hyperparasitoids were collected from three genera of hyperparasitoids, and were most common in the field in July and August. Using Magnetic Resonance Imaging (MRI) techniques to study parasitism in insect hosts Marianne Alleyne1 and Luisa Ciobanu2 1Department of Entomology, University of Illinois at Urbana-Champaign, Illinois, USA, vanlaarh@life.uiuc.edu 2Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Illinois, USA The development of parasitoids within a host is usually visualized with the help of histological serial sections and subsequent reconstruction of the structures from these sections. A big drawback of this technique is the loss of the host and parasitoid, making studies of subsequent development of the same parasitized host impossible. Non-destructive imaging procedures could potentially give us new insights into how parasitoids survive and develop within a host. The goal of the present investigation was to assess the use of NMR imaging (MRI) for the study of endoparasitoid development. For this study we imaged Manduca sexta larvae parasitized by Cotesia congregata 6 to 12 days after parasitization and compared the images to those of unparasitized larvae. In order to limit manipulations larvae were not anaesthetized or injected with contrasting dyes. Larvae were contained within a tube for about 30 min during each imaging session. Experiments were performed using a 600 MHz NMR spectrometer. 600 MHz represents one of the highest frequencies at which animal micro-imaging experiments have been successfully performed to date. This frequency level affords the maximal spatial resolution and contrast currently available. We were able to obtain images from larvae on consecutive days. Parasitoids emerged from parasitized larvae successfully, even after 3 or more imaging sessions. Images clearly showed different regions, within the body as a whole and within the 1 mm imaging-slice, containing primarily water or fat molecules. However, we were unable to distinguish between parasitized and unparasitized larvae, presumably because the fat in a parasitoid larva is indistinguishable from fat within the fat body using this technique. Mortality and fertility of Aphelinus near parmali at four temperatures