Wednesday, March 23, 2011

Not so giant swallowtail

Yesterday I noticed that one of the two Papilio cresphontes (giant swallowtail) chrysalids was starting to show wing color, so I knew it was a matter of hours before the butterfly would emerge.  When butterflies are close to emerging, the chrysalis appears to darken or change color, but it has actually become semi-transparent, and what you are seeing is the adult butterfly.  Often, you can see the spots or stripes on the wings or body.  This photo shows the difference between the two swallowtail chrysalids I have - the yellow bands on the black wings are visible, as well as a yellow stripe down the side of the abdomen, compared to the other chrysalis which is still mostly green and brown.
This morning, I awoke to find the swallowtail beginning to flutter about in the cage.  With a wingspan of only 4 inches, he is on the small side for a butterfly that can have up to a 6.25 inch wingspan and is the largest butterfly species in North America.  Giant swallowtails feed on trees and plants in the citrus family, and as such, can sometimes become pests in citrus groves.  It ranges throughout the eastern United States, but is most common in the southeast, and has been spreading to California in the orange groves.
The left hindwing is slightly damaged as you can see in these photos. There are a number of possible causes for that, including insufficient nutrition as a larva, rapid temperature fluctuations during adult development, or simply an obstruction when emerging from the chrysalis or while pumping and drying the wings.
Dorsal view of male giant swallowtail
Ventral view of male giant swallowtail
Giant swallowtail and chrysalis