Labrum Spectrum

Crane flies generally do not eat once they’re adults, but they do drink – and this labrum, or mouthpart, of a crane fly is well adapted to a liquid diet. Although crane flies look like giant mosquitoes, you can ease your mind knowing that they don’t bite.

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A higher magnification of the cane fly labrum

Labrum Spectrum

What am I looking at?

This is the mouthpart, also called the labrum, of an adult crane fly. The head of a crane fly has a snout-like protrusion, in front of the eyes, coming out of its face. You are looking here at the very tip of that protrusion. The whole surface is covered in ribbed channels, or tubes, called pseudotrachea (1) that wick liquid food, such as flower nectar, into the four larger tubes (2) that converge in the center at the labrum’s opening (3). The colors in this image represent depth, with warmer colors like red and yellow being closer to the viewer and cooler colors like blue being farther away.

Click on the right arrow to see another view of a crane fly’s labrum.

Biology in the background

As adults, most crane flies do not eat solid food, or do so very infrequently. However, they do suck up nectar from flowers. The larval stage (after the fly hatches but before it becomes an adult) is the main eating stage of a crane fly’s life. Crane fly larvae gorge themselves on grass, decaying wood, seedlings, and other vegetation until they are ready to transform into an adult. By the time the fly emerges as an adult, it has enough stored food energy to survive for a few days – just long enough to mate and reproduce.

A crane fly’s labrum can grow up to 1 millimeter long, or roughly 13 times wider than a human hair.

Technique

This image was created using confocal microscopy.