Male tiger swallowtails almost always are yellow with vertical black stripes. Females’ wings may be yellow or solid black, with the black replacing the broad yellow expanses. Regardless of the coloration, the females’ hind wings are marked by bluish and red wing scales.
Biologists believe that the black coloration in some females may add protection by mimicking the poisonous pipevine swallowtail butterfly, which most predators avoid.
A female tiger swallowtail lays up to 250 eggs during her short, two-week lifetime. Although she may sip nectar from a variety of flowers, she lays her eggs only on “host plants” preferred by tiger swallowtail caterpillars — tulip poplar, wild cherry, sweet-bay, basswood, ash and wafer ash trees. The caterpillars hatch in 10-14 days and then feed voraciously for about four weeks before forming chrysalises and developing into adults.
IN THE SKY: From David Dundee, Tellus Science Museum astronomer: The moon will be new on Thursday. Mars and Venus are low in the west at dusk. Venus will appear near the moon Saturday night; Mars will do so on Sunday. Jupiter and Saturn rise in the east after midnight.
Charles Seabrook can be reached at firstname.lastname@example.org.