Help with yellow belly

I just hatched my first clutch and im struggling to tell if any of my bumble bees are bumble bellies. I have one male thats about a shade lighter than the others so hopin he has yb. The male in question is in the first pic his sister is the second.
http://i1070.photobucket.com/albums/...ps8nornolc.jpg

http://i1070.photobucket.com/albums/...ps3gpukvn7.jpg

In that combo, yb is very hard to ID, at least from my experience. I have a bumble belly breeder female and the breeder I got her from couldn't confirm she had yb either, I had to prove her out through breeding. Even then, most of the babies that had 2-3 morphs were very difficult to ID if they had yb but a few of the single morph babies we were able to confirm the yb. Your probably going to have to label them as possible yb until they can be proven through breeding. Who knows though, maybe someone here knows how to positively ID them and if so I'd love to hear how.

Isnt the checkered belly make it a yb though? The belly looks very similar to the fathers who is yb

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Originally Posted by Bdidz

Isnt the checkered belly make it a yb though? The belly looks very similar to the fathers who is yb

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Yes but it's not actually the belly, it's like the edges of the belly and it doesn't always show on the bumblebees.