D3212: Imaging challenges in surveying the egg development of caterpillar larvae (Trichoplusia ni) and parasitoids (Trichogramma brassicae) in vivo: Preliminary original results obtained with micro-CT scanning technology

Trichoplusia ni is a prolific cruciferous crop pest. The most common treatment of T. ni outbreaks in crop management programs is the use of pesticides. However, negative effects of pesticide overuse, non-target organism toxicity and insect resistance has led to the recognition of the importance of Integrated Pest Management (IPM), as a strategy for sustainable agriculture. One effective alternative strategy is the use of biocontrol, for example the use of parasitoid Hymenoptera species like Trichogramma brassicae, in the treatment of outbreaks of Lepidopteran pests in an agricultural setting. When studying these insects, the difficulty of scale becomes readily apparent. Eggs of T. ni measure on average 0.6x0.4mm. T. brassicae, as adults, have an average body size of 0.5mm. Most techniques for observing the development of these insects in such a minute system are destructive in nature, requiring fixatives, dyes, and/or dissections. Here, we apply micro-CT scanning technology (CT: computed tomography) and use a Skyscan 1174 micro-CT scanner (Bruker microCT, Belgium), to generate three-dimensional images of insect development, in vivo. Appropriate post processing clarifies images and highlights physiological structures of interest within unmodified Tricholoplusi ni eggs. Presenting a novel means for non-destructive observation at a micro scale.