Photo credit above: Jenny Shrum
Life History
New Egg (soon to turn orange) Young Larva Mature Larva Pupa or Chrysalis Adult or Butterfly
This egg is located on the native host plant Lepidium virginicum ssp. menziesii. Photos of larval instars and pupa shown above were all taken at San Juan Island National Historical Park captive rearing facility. Adult (top right) released from captive rearing facility.
Photo credits, left to right: Jenny Shrum, SJINHP, SJINHP, Shrum, Shrum
After pupa has transformed into an adult and emerged through the narrow diagonal opening near the top of casing (above). All adults emerge like this.
Photo credits above: Jenny Shrum |
An adult that has crawled to the top of a wooden rod after emerging from its chrysalis. This young adult has yet to pump fluid into its wings.
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Adult after release from captive rearing in dune habitat on Sisymbrium altissimum host plants.
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Eleven Months as a Chrysalis
While most butterflies transform from pupae to adults in a matter of weeks, the island marble butterfly spends most of its life—or about eleven months—in diapause, a period of suspended development, during the pupae life stage. The island marble butterfly is vulnerable during this time, requiring a stable, protective environment in grass or vegetation near host plants. This feature of the island marble butterfly's life history requires caution when visiting habitat to ensure that well-camouflaged chrysalises are not squashed or disturbed. It is extremely difficult to find chrysalises in the wild, so much so that even scientists studying the butterfly, have a hard time finding chrysalises in island marble butterfly habitat. Respect habitat and stay on trails.
Adult butterflies emerging from chrysalises mid-April through June pollinate nectar flowers and then mate before completing their life cycle. Females lay eggs on the flowers of mustard host plants. Eggs and larvae must survive predation by native wolf and ground spiders and invasive wasps. Eggs and larvae must also survive deer browsing the tips of host plants, the exact part of mustard plants that eggs and young larvae need to survive. The few larvae that survive to the last larval stage "wander" up to approximately 13 ft. (4m) from the host plant into nearby grass and other vegetation to become chrysalises. Individuals remain as chrysalises until metamorphosis into a winged adult occurs during the following spring. Data from Lambert 2011.
Reference: Lambert, A. 2011. Natural history and population ecology of a rare pierid butterfly, Euchloe ausonides insulanus Guppy and Shepard (Pieridae). [Doctoral dissertation]. University of Washington.
Reference: Lambert, A. 2011. Natural history and population ecology of a rare pierid butterfly, Euchloe ausonides insulanus Guppy and Shepard (Pieridae). [Doctoral dissertation]. University of Washington.
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Island Marble Butterfly Volunteer Program San Juan Islands Conservation District 530 Guard St Friday Harbor, WA 98250 [email protected] (360) 375-3070 |
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