Tiger SwallowtailPterourus glaucus

malefemale

What is up with this Tiger Swallowtail?

malefemale

An actual specimen: no photoshop!

It’s a gynandromorph!

• “gyn” means “female”• “andro” means “male”• “morph” means “form”• “Gynandromorph” literally means part

female and part male.

How does this happen?•Normally, in moths & butterflies:

XX = MaleXY = Female

•If the butterfly has two or more “X” chromosomes, it will develop as a male. With only one “X” chromosome, it will be a female.

•In arthropods, the first cell division differentiates left from right.

•Bilateral gynandromorphs arise by mitotic nondisjunction in the sex chromosomes at this one-two cell stage.

XX

XXduplicated

XXXmale female

X

Example #2

Male Female

Example #3

Example #4

Another Example: Blue Crab

malefemale