Black Swallowtail

Naming

The species is named after the figure in Greek mythology, Polyxena, who was the youngest daughter of King Priam of Troy.

Distribution

"Papilio polyxenes" are found from southern Canada through to South America. In North America they are more common east of the Rocky Mountains. They are usually found in open areas like fields, parks, marshes or deserts, and they prefer tropical or temperate habitats.

Behavior

Females lay single eggs on host plants, usually on the new foliage and occasionally on flowers. The eggs stage lasts four to nine days, the larval stage 10-30 days, and the pupal stage 18 days. The duration of these stages may vary depending on temperature and the species of the host plants.

Reproduction

Eggs are pale yellow. Young larvae are mostly black and white with a saddle, and older larvae are green with black transverse bands containing yellow spots.

The "Papilio polyxenes" demonstrates polyandry and a lek mating system, showing no male parental care and display sites. Females are therefore able to choose males based on these sites and males are the only resource the females find at these sites.

Food

"Papilio polyxenes" utilize a variety of herbs in the carrot family, but will choose the food plants for their larvae based on visual and chemical variations. Host plant odor is one of the cues involved in the selection of landing sites for oviposition. The responses to these cues are innate, and feeding on a host plant as a larva does not increase the preference for that plant as an adult.

Species of host plants include:
⤷  Mock bishopweed, "Ptilimnium capillaceum"
⤷  Roughfruit scaleseed, "Spermolepis divaricata "
⤷  Spotted water hemlock, "Cicuta maculata "
⤷  Water cowbane, "Oxypolis filiformis "
⤷  Wedgeleaf eryngo, "Eryngium cuneifolium "

Defense

Male butterflies secure territories to use in mate location and courtship. These territories contain no significant concentration of nectar sources, larval host plants, or night settling sites. Once secured, a male will maintain exclusive use of a territory 95% of the time. Males will aggressively chase other males who approach their territory, and then return to their territory. Success in defending a territory depends on the number of competitors and his previous success, but the size of the male is not a contributing factor. Males that emerge early in the brood are more likely to defend a female-preferred territory. These males will have early access to available territories, and will choose the ones that are most preferred by females. What makes a territory desirable by females remains unknown, and is only measured by the number of aggressive encounters between males and the overall mating frequency at these sites

Male territories are generally of high relative elevation and topographic distinctness. This feature serves as an advantage to the lek mating system described later, as males will be concentrated in predictable locations and will be easy to encounter by females.