Reason for BST chrysalis color

bernergrrl(z5 IL)June 21, 2014

I have 6 BSt chrysalides, and 5 are green, and one just needs to be different, and is brown.

They all are using the same materials to pupate on--I have one of those butterfly cages. Three are on top--2 are green, one is brown (the rest have pupated on stems down below).

I remember this being discussed here--and there questions about whether it related to whether the butterfly would overwinter or it was related to what the caterpillar pupated on.

I did a little internet search, and found this bit on Wikipedia (Wiki's source is Butterflies of Canada). Article states that it has to do with "genetic balance that ensures the majority of pupae will blend" into the background.

Makes sense--if caterpillar pupates somewhere brown, then it's likely to survive.

What do you all think? Any other reasons? I like learning these things. :)

Here is a link that might be useful: Wiki article

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runmede(7a Virginia)

They just want to fool the birds. ZSTs for example have at least 4 different colors of larva. Once a bird patterns food it will search for that color. They also have green and brown pupa, but I have had a spring brood green pupa wait until the next spring to emerge.

Sometimes BSTs will take the color of what they pupate next too with variations from whitish to greenish to brownish.

    Bookmark   June 21, 2014 at 1:05PM
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alex928 Z8/LA

One of my BST caterpillars became my first brown chrysalis this morning (all the others I've seen before were green). Actually he looks about the same color of the gray leafless stick he pupated on, which isn't exactly brown...he's more of a dark grayish color, so I'm not sure brown is really the right description. It also seems a bit small for something a butterfly is supposed to come out of, but it's been a while since I've seen a BST chrysalis, so my size expectations may be a bit distorted, and he may be normal-sized for all I know.

    Bookmark   July 7, 2014 at 10:03AM
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october17(5chgo)

This is the first year that all my BST crysalis' are green. There are usually more brown with a few green. Weird, isn't it?

    Bookmark   July 7, 2014 at 10:20PM
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bernergrrl(z5 IL)

It makes sense to mix up the chrysalis color like Runmeded said. Love those ZSTs by the way--hope someday they come back to this area of IL.

    Bookmark   July 8, 2014 at 10:23AM
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runmede(7a Virginia)

I found a nice blog that explains the coloration better.

Here is a link that might be useful: Variations on Theme Chrysalis Color

    Bookmark   July 8, 2014 at 10:34AM
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october17(5chgo)

I now have two brown ones. The brown ones are on white netting I use to protect them. But there were three green ones on the white netting too. Weird.

    Bookmark   July 11, 2014 at 6:48PM
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