Animal Behavior 11e Video 7.2: Male speckled wood butterflies fighting

Ascending flights of competing male speckled wood butterflies. These interactions, which determine who gets to perch in the sunspot, became famous when the claim was made that the winner was invariably determined by which male was resident at the site, a claim that has now been rejected. (Courtesy of Christer Wiklund.)

Textbook Reference: Why Give Up Quickly When Fighting for a Territory?, p. 230