04 February 2008

A yellow isopod


The common isopod Armadillidium nasatum, shown in the photo above, is ordinarily grayish-brown in color. Yesterday, taking advantage of the warmer weather, I went out in the backyard to see how the creatures under the rocks were coming along. Among the assorted slugs, earthworms, millipedes and isopods, there were 2 yellow isopods under 2 separate rocks.


I photographed them and took one of the specimens. They were easy to identify as A. nasatum from the prominent projection on their heads (arrow), a characteristic of the species. When disturbed, they roll up into a ball (not every terrestrial isopod species can do that).


I also e-mailed photographs of the yellow isopods to my usual isopod contacts, Joan Jass in Milwaukee and Ferenc Vilisics in Budapest. They have since informed me that such yellowish color morphs are occasionally seen in A. nasatum populations.


Wanderin' Weeta said...

Hey! I photographed one like that last year. I thought it was odd, but someone told me it was just newly molted.

Was he wrong, and it was a morph, after all?


I also thought that they were perhaps newly molted individuals. But the one I took was, as of last nite 2 days later, still the same color. I will post an update in a week or so.

Katie said...

Ah, yes. These Isopods are the bane of my orchid collection. They love to get into the pots when I summer my orchids outdoors. But, be that as it may, I have always been fascinated by them. I have yet to see a yellow morph though.

Wanderin' Weeta said...

Good! I'll be watching for your update.