Caterpillar fluorescence

Here we present a selection of white light and fluorescence images of caterpillars taken in Maine and Vermont (USA). We’re not caterpillar experts here, so if you let us know the genus/species of any of these we will gladly add that information. Most of the images were made at night, first exploring in the dark with steady blue light and then photographing the subjects using either steady light or an electronic flash fitted with a fluorescence excitation filter. Some of the photos were made during the day using the technique described in the article Fluoresence Photography without Darkness.

Most of the caterpillars glow green when excited with blue light, with the fluorescence an enhancement of their color under white light. The background red you see in most of the images is fluorescence from chlorophyll in the plants. In a few of the images you can see a reddish glow that appears to come from within the body. This may be chlorophyll in the caterpillar’s gut.

(Click any image for larger view)

Inchworms

Tomato hornworms

Tomato hornworms are the caterpillar stage of the five-spotted hawk moth (Manduca quinquemaculata). These hungry caterpillars can be a big problem for tomato growers. Although the caterpillars can be quite large they blend into the plant extremely well, making them tough to spot in white light. In fluorescence, however, they are really easy to spot.

Tent caterpillars

Tent caterpillars in a tree in Vermont.

Various caterpillars

An assortment of caterpillars photographed in Maine.