Butterfly egg: Vanessa kershawi, Australian Painted Lady

Egg of the butterfly Vanessa kershawi, Australian Painted Lady. Scale bar = 0.25 mm.

A recent book published by Museum Victoria, Butterflies: Identification and life history by Ross Field, included images of the eggs of each of the approximately 140 species of Victorian butterfly. Many of these had never been photographed before. This often required the eggs to be collected and watched until they hatch to confirm what species they were.

Butterfly eggs are very small, most are less than 1 mm across. Because the eggs are so small a microscope has to be used to take photos of them that show any detail. However, the field of view down a microscope is very shallow so only a small piece of the egg is in focus at once. To get a clear, focused picture of a single egg a series of 60-80 images have to be taken, each at a different focal plane, that are then combined into a single image using montaging software.