Eurycea larvae changing colors

[KevinS]

I collected over a dozen larvae that may represent a mixture of E. cirrigera and E. longicauda. I'm having a hard time identifying them because they've lightened in coloration so much since I collected them. Here's a shot of some right after they were collected in the field.

Notice how 2 are dark with visible pattern and 2 are pale and nondescript. Since I brought them home, all of them have gone to this pale color scheme and I can't use a lot of pattern and pigment characteristics to key them out as a result. I've tried keeping them cold and at room temperature. I've also tried keeping them in natural light and in total darkness for over 12 hours. After keeping them in darkness one larva out of 6 in a container darkened up some more, otherwise no success. Do you guys have any other suggestions?

 

[taherman]

Hi Kevin,

Try putting them in a black container with a few dark stones/leaves they can hide under. They all look bislineata-like to me. From what I understand longicauda should not have those light spots down the back, which are visible on all the larvae in the photo. That's my best guess, though I could be wrong.

-Tim

 

[slowfoot]

The larvae will become lighter if they're kept on a plain background - they'll change color to match the background. Try adding a substrate, like gravel, to get them to darken.

 

[KevinS]

Hi Kevin,

Try putting them in a black container with a few dark stones/leaves they can hide under. They all look bislineata-like to me. From what I understand longicauda should not have those light spots down the back, which are visible on all the larvae in the photo. That's my best guess, though I could be wrong.

-Tim

I agree that those in the picture look like cirrigera, but there are a few in the bunch that are different (one has a black mid-dorsal stripe for example). I had thought keeping them in darkness would be my best bet but I am going to get a bunch of dark gravel from our stream this evening and see if that helps. Thanks.