A female Clodius Parnassian butterfly resting on an ox-eye daisy. The whitish structure on her abdomen is a sphragis, a mating plug deposited on her g

- Image ID: JWWG5W
Buddy Mays / Alamy Stock Photo
Image ID: JWWG5W
A female Clodius Parnassian butterfly resting on an ox-eye daisy. The whitish structure on her abdomen is a sphragis, a mating plug deposited on her genitalia after mating by the male so that she can't mate again, thereby avoiding sperm competition.