Species Papilio troilus - Spicebush Swallowtail - Hodges#4181

4181

Pterourus troilus - new name according to Minno et al, 2005 (1)

Papilio troilus Linnaeus, 1758

Wing span: 3 - 4 inches (7.5 - 10 cm).(1)

Adult: Upper surface of forewing is mostly black with ivory spots along margin. Upper surface of hindwing has orange spot on costal margin and sheen of bluish (female) or bluish-green (male) scales. Underside of hindwing with pale green marginal spots.(1) Median spotband on underside of hindwing missing one orange spot.(2)

Caterpillar: First three instars resemble a bird dropping. Last two instars are green with large eyespots - the two largest on third thoracic segment have black "pupils", two smaller ones on first abdominal segment do not. The larva changes color to orange or yellow just prior to pupating.

e. US, se CAN - Map (southern Canada to Florida; west to Oklahoma and central Texas). Occasionally strays to North Dakota, central Colorado, and Cuba.(1)

Deciduous woodlands, fields, roadsides, yards, pine barrens, wooded swamps, and parks.(1)

2 generations per year from April-October. In Florida, several generations between March-December.(1)

Caterpillar hosts: Spicebush (Lindera benzoin), Sassafras trees (Sassafras albidum), Pondspice (Litsea aestivalis) Red, Swamp and Silk Bays (Persea spp.); perhaps prickly ash (Zanthoxylum americanum), Tulip tree (Liriodendron tulipifera), Sweetbay (Magnolia virginiana), and Camphor (Cinnamomum camphora).

Adult food: Nectar from Japanese honeysuckle, jewelweed, thistles, milkweed, azalea, dogbane, lantana, mimosa, and sweet pepperbush.(1)

Males patrol in woods, roads and woodland edges to find receptive females. Females lay single eggs on underside of host plant leaves. Caterpillars live in shelters of folded-over leaves and come out to feed at night. Some chrysalids from each generation hibernate.(1)

The first instar caterpillar measures 4-5 mm. It reaches approximately 50 mm. when mature. The cycle from egg to adult takes about 6 weeks unless the chrysalis hibernates

1. egg. 2. first instar caterpillar. 3. third or fourth instar. 4. final instar. 5. final instar, ready to pupate. 6 pupa or chrysalis. 7. adult female. 8. adult male

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The Palamedes and Spicebush Swallowtails may face problems over the next several years associated with the introductions of the Redbay ambrosia beetle (RAB), Xyleborus glabratus, and the fungus causing laurel wilt.

Redbay ambrosia beetle (RAB),Xyleborus glabratus, and laurel wilt, caused by the fungus Raffaelea lauricola, together constitute an insect-and-disease threat. The redbay ambrosia beetle serves as an insect vector for the fungus causing laurel wilt, a destructive disease of redbay (Persea borbonia) and other trees in the laurel family, including swampbay (Persea palustris), sassafras (Sassafras albidium), spicebush (Lindera spp.), and pondspice (Litsea aestivalis). Lindera melissifolia is a federally listed endangered plant, and Litsea aestivalis is listed as a threatened plant in multiple states.

The non-native redbay ambrosia beetle was first detected in Georgia in 2002; the associated pathogen, a highly virulent, invasive, wilt-inducing fungus, is believed to have arrived in the United States along with the beetle. Investigators believe that RAB was introduced into the United States in wooden crating material from Southeast Asia. Both RAB and laurel wilt have been observed as far north as Myrtle Beach, South Carolina. Mortality has been documented to spread about 20 miles per year on average.

Redbay and swampbay are prominent species in North Carolina’s coastal plain. In addition, pondspice and spicebush are found in the coastal plain and sassafras is found throughout the state. Laurel wilt has the potential to extirpate (cause local extinction) of any of these species in the Lauraceae family from much of the coastal plain. As the insect and pathogen go through an area, all affected plants eventually wilt and die. Dead foliage persisting on plants in areas with high densities of bay species will create fire hazards due to dead, dry aerial fuels. Because redbay trees resemble young live oaks, they are popular choices for retention during development in urban areas along the coast.

Various species of wildlife would also be impacted by the reduction or elimination of laurel wilt host species. Songbirds, bobwhite quail, and turkeys often feed on the fruit, while deer and bears frequently feed on foliage and fruits of redbay and sassafras. Several rare species of swallowtail butterflies rely heavily on redbay, sassafras, and spicebush for completion of their life cycle. At this time, no reliable controls exist for either the Raffaelea lauricola fungus or the Xyleborus glabratus insect vector.

This is notification (March 2011) that redbay ambrosia beetles and the fungus that causes laurel wilt have been identified and isolated/confirmed in North Carolina - the Colly area of eastern Bladen County. There are indications that it may also be present in as many as four other nearby counties, but at this time we are awaiting confirmation before we can say for sure. However, even without proper confirmation we are sure that near future natural spread to nearby counties is imminent. Laurel wilt has been found to move about 20 miles/year naturally, but can move faster with assistance from humans moving redbay/swampbay firewood, wood chips, tree trimming debris and wood products.

RAB and laurel causes mortality in all Lauraceae species including bays (Persea spp.), Sassafras, pondspice and pondberry. Information about the insect/disease can be found at the bottom of this email. In addition, a comprehensive website about laurel wilt can be found at: www.fs.fed.us/r8/foresthealth/laurelwilt/index.shtml

Adults are very similar to the Black Swallowtail, but may be distinguished by missing one orange spot in the median spot-band on the hind wing (underside). Above, this species might be confused with Pipevine Swallowtail: both have blue on the hind wing, but the latter species has fewer and smaller markings on the front wing.

Late instar larvae are similar to those of the Palamedes Swallowtail, but the underside of that species is rusty-brown or maroon beneath, this one is gray. Both have a blue spot on the first abdominal segment, which on Palamedes is adjacent to the eyespot but on Spicebush is within it.

Spicebush Swallowtail Palamedes Swallowtail

Glassberg (2)

Brock and Kaufman (3)

Scott (4)

Allen (5)

Minno, Butler & Hall(1)

Wagner(6)

BAMONA (1)

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