Half of this butterfly is male and the other half is female. This is not photoshop or a frankenbug from one of our collections.
Bilateral asymmetrical gynandromorphism can occur in some arthropods. They can form from either the loss of a sex chromosome early in development or from the fertilization of a binucleated egg. In Lepidopterans, males are ZZ (homogametic) and females are ZW (heterogameti
c). The most common way an individual Lep could have ZZ and ZW cell karyotype is through the double fertilization of a the binucleated egg (Z+W).
This two headed albino milk snake was born last year in Florida.
The condition is known as Polycephaly and occurs when monozygotic twins fail to separate completely. Most organisms with this condition will not live for long, but occasionally you will get cases like this one, where the snake(s?) seem healthy enough and can live for years.
The heads act independently of one another, and will fight over food given the opportunity. Watch a video of their owner feeding them here: http://bit.ly/11YYkHT