Moth caterpillar embryos and parasitoid egg infection as revealed in vivo and visualized by micro-CT scanning.

The Lepidopteran pest Trichoplusia ni and the parasitoid wasp Trichogramma brassicae represent a fascinating biological system, important for sustainable agricultural practices but challenging to observe. We present a nondestructive method based on micro-CT scanning technology (CT: computed tomography) for visualizing the internal parts of caterpillar embryos and of emerging parasitoids from infected eggs. Traditional methods of microscopic observation of the opaque egg contents require staining or dissection. To explore the biological system nondestructively, we optimized the application of micro-CT scanning to construct 3-D images of insects in vivo.