Courtship behavior Courtship behavior in
Dryas iulia involves a very specific sequence of steps that can be categorized into three sequential phases: an aerial phase, an air-ground phase, and a ground phase. The observed courtship steps are outlined in detail below: First, the male
D. iulia approaches the female from behind. Then, the female takes flight, with the male flying in front of and above the female. This position is taken by the male so that the female can smell the male's
scent scales and become sexually stimulated. Next, the female attempts to fly higher than the male, which can be seen as an anti-copulatory behavior, before landing. After that, the male
D. iulia continues to beat his wings above and in front of the female, while both face the same direction. The female butterfly then opens and vibrates her hind wings and front wings. Her hind wings are fully opened, while her forewings are only partially so. At the same time, the female emits scent glands from her raised abdomen. The male then beats his wings behind and then in front of the female once again. If the female is satisfied by the courtship, she lowers her abdomen and shuts her wings in preparation for mating.
Mating behavior Mating can occur within two weeks of the Julia butterfly's exit from the chrysalis. As adults, male
D. iulia spend the majority of their time searching for females to mate with. Females of this butterfly species can mate four times in their lifetime, which is unusual for female
Heliconius butterflies who generally mate just once. Many mating behaviors in
D. iulia are sex-specific and can include receptive and non-receptive behaviors by the females of the species. Some female behaviors regarded as showing non-receptiveness include abdomen raising and overflight, in which the female attempts to fly higher than the male during the aerial phase of courtship. On the other hand, a female behavior such as shutting her wings has been found to be a key receptive behavior. For males, persistence did not seem to be a key driver of success, as behaviors performed by persistent males, such as hovering over the female did not often lead to copulation. The inability of persistent males—meaning those that carried on extended courtship behavior – to increase copulation has led to researchers theorizing female copulation acceptance as the primary determinant of successful copulation in
D. iulia. For example, the only male behavioral acts found to be indicative of successful copulation occurred in response to signals of female receptiveness.
Evolutionary basis of sexual selection and conflict Julia butterfly copulation is always terminated by the males after the ground phase. The female remains at the mating site as the male flies away. This raises the idea of an evolutionary basis for this behavior based on a conflict of interests between males and females of the species. This conflict arises because of a difference in reproductive interests between the male and the female that has its beginnings in
anisogamy. Sexual selection studies favor forms of sexual conflict such as this one to be one of the major sources of
speciation in certain insects. The methods of
mate selection (by which a female accepts or denies a male suitor) are not completely understood. Some studies have reported the
sexual dimorphism (of color and body size) of the butterfly as a key factor that may suggest an evolutionary basis towards understanding sexual selection.
D. iulia male butterflies have been seen to chase females of butterfly species with similar visual cues, which has led researchers to believe that these visual recognition strategies form the basis of sexual partner selection in this species. However, more research is needed to identify how different aspects of
D. iulias physical features factor into mate selection. == Interaction with humans ==