Creature Feature: Spicebush Swallowtail

A stand of Spicebush along the creek results in an abundance of Spicebush Swallowtails Papilio troilus flying low and fluttering their wings while they feast on summer's abundant flowers. 

Walking through the woods in late summer, you might be rewarded if you examine Spicebush leaves, especially leaves that are rolled over.  Lurking inside this leaf-retreat, is what appears to be a snake or maybe a tree frog (exactly what the caterpillar wants predators to think!)  They might even rear up and retract their head to increase the illusion.  

A true mimic, early stages of the caterpillar resemble bird poop, and the adults resemble the poisonous Pipevine Swallowtail Battus philenor

 Spicebush Swallowtail caterpillar    Photo courtesy of Ellen Reynolds, Beagle Ridge Herb Farm

Spicebush Swallowtail caterpillar    Photo courtesy of Ellen Reynolds, Beagle Ridge Herb Farm

 Photo by Bill Dunson

Photo by Bill Dunson

Do you remember the butterfly life cycle?

Butterflies feed on nectar from a variety of flowers, then the females lay eggs on a suitable host plant.  While some butterflies lay eggs on a variety of plants, more often they limit themselves to a specific plant, such as Monarchs Danaus plexippus and Milkweed Asclepias spp., or a plant family such as Spicebush Swallowtails Papilio troilus and the family Lauraceaea  which includes Spicebush Lindera bezoin and Sassafras Sassafras albidum.  

In addition to sight, females utilize chemical receptors on their forelegs to assess the chemicals in the leaf to decide if it is an suitable host. Once the eggs hatch,  caterpillars eat the leaves of the host until they are large enough to pupate.  Then they will spin a chrysalis and complete their transformation into a butterfly.