05/31/2026
Species Features May:
California Pipevine Swallowtail, Battus philenor hirsuta
AND
California Pipevine, Aristolochia californica
Stacey: At this time of year, you can find me on the Sacramento River Trail, lovingly relocating these spicy little caterpillars off the trail and out of harm’s way on to a patch of California Dutchman’s Pipevine. If you have been out in about in nature this time of year as well then you have likely also seen seen these little guys (adult or caterpillar stage). These insects are endemic to California and have a close personal relationship with our California Pipevine, in that eggs are laid on the underside of pipe leaves and after the eggs hatch, larvae begin feeding on the tender young shoots, in fact these caterpillars feed exclusively on the plant, making the plant a host plant for the species...
Ren: This month we’re doing a special rerun of California Pipevine in order to investigate the life cycles of two species: Aristolochia californica and Battus philenor hirsuta
My personal goal to document the stages of our pipevine plant began in late January, and continues into May. The first to appear were the pipe-shaped flowers, filled with tiny insects, dangling from vines climbing up oak branches and crawling over brambles. Then the leaves began to outnumber the flowers; green hearts covering the ground. A beacon for the only creature able to withstand their toxic nature: Battus philenor hirsuta. The California Pipevine Swallowtail is black and blue with white markings and orange dots along the bottom of its wings. They exclusively lay their eggs on California Pipevine, which will hatch within 4-10 days.
The first pipevine swallowtail that caught my eye was on March 1st, and their numbers exploded soon after. My mission continued...
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(Timeline Photography by Ren Redlich, Drawing from the journal of Ren Redlich, Image Credit: Biologist Tim Wong)
