1. Tiger Swallowtail Pterourus glaucus
female
male

2. What is up with this Tiger Swallowtail?
male
female

3. An actual specimen: no photoshop!

4. It’s a gynandromorph! “gyn” means “female” “andro” means “male”
“morph” means “form”
“Gynandromorph” literally means part female and part male.

5. How does this happen? Normally, in moths & butterflies: XX = Male
XY = 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.

6. XX XX
duplicated
XXX
male
female X

7. Example #2
Male
Female

8. Example #3

9. Example #4

10. Another Example: Blue Crab
female
male