Skip to content
Center for Plant Conservation
  • Login
  • Register
  • Get Newsletters
  • Donate
  • Discover Our Work
    • 2025 National Meeting
      • Sponsor the National Meeting
      • Past National Meetings
      • 2025 Photo Contest
    • CPC Rare Plant Academy
      • Video Library
      • Photo Gallery
      • Applied Plant Conservation Course
      • Community Forum
    • National Collection
    • CPC Best Practices
      • Read Best Practices Online
      • Download Best Practices PDF
      • Purchase Best Practices Book
    • Pollinator Database
    • California Plant Rescue
    • Florida Plant Rescue
    • Rare Plant Finder
    • Seed Longevity Study
    • Rare Plant Reintroduction
      • Reintroduction Registry
      • CPC Reintroduction Database
  • Rare Plant Academy
    • Video Library
    • Photo Gallery
    • Applied Plant Conservation Course
    • Community Forum
  • Get Involved
    • Donate
    • 40th Anniversary
      • 40th Anniversary Campaign
      • 40th Anniversary Summit Event
    • Sponsor a Plant
    • Advocacy
    • Become a Partner
    • Get Newsletters
    • Register
    • Member Payments
    • Sponsor the National Meeting
  • Meet Our Community
    • CPC Newsletter
    • Conservation Partners
      • Institutional Partners
      • Individual Partners
    • CPC Star Awards
    • Fellowships
    • Community Forum
  • Support
    • Donate
    • Sponsor a Rare Plant
    • Shop CPC Merch
  • About
    • Team and Mission
    • Reports & Financials
    • Board of Trustees
    • Employment Opportunities
    • Press Room
    • Contact Us
  • Donate
  • Get Newsletters
  • Login
  • Register
National Tropical Botanical Garden

Who’s Your Pollinator?

Seana Walsh

Rappelling down cliffs on Kauai, sometimes suspended a thousand feet above the Pacific Ocean, botanists hand pollinated the critically endangered Hawaiian flowering plant, Brighamia insignis (Alula) in an attempt to save them now that its native pollinator is all but extinct.

There had been speculation that the natural pollinator of both Brighamia species was a native hawk moth that is now either extremely rare or extinct. No hawk moth had ever been observed visiting either species. To determine if the natural pollinator was a hawkmoth, Seana Walsh completed her master’s thesis research on the floral biology, breeding system, pollination ecology, and ex situ genetic diversity of Alula. Building on the four decades of work by botanists Steve Perlman and Ken Wood, Walsh examined floral traits to support or refute the hypothesis that Alula evolved a moth pollination syndrome. She conducted pollen manipulations on cultivated plants to assess the hypothesis that Alula is self-incompatible, that is, it cannot self- pollinate.

Alula is endemic to the island of Kaua‘i and historically to Ni‘ihau. Moth pollination for Alula was proposed based on a few floral trait observations; however, no moth pollinator has ever been observed visiting Alula flowers. There are three native endemic species of moths commonly known as hawk moths, sphinx moths, and hornworms that are reported to occur on Kaua‘i, but other species may have gone extinct. These three species are Hyles calida, Manduca blackburni, and Tinostoma smaragditis. Tinostoma smaragditis (or the Fabulous Green Sphinx of Kaua‘i) is only known from about 19 collections and was last seen in 2000. It is not unreasonable to speculate that the Fabulous Green Sphinx of Kaua‘i could be the single or one of several, native pollinator(s) of Alula.

Examining floral traits provided support for the hypothesis that Alula is adapted to moth pollination. Overall results of pollination treatments suggested a breeding system that was primarily based on cross-fertilization. The results of manipulative pollinations were difficult to interpret with any confidence, however. The quantity and quality of pollen produced was extremely low. Based on 29.5 daytime and 21.5 nighttime floral observation hours, it appears unlikely that anything is effectively pollinating Alula outplantings at the National Tropical Botanical Garden’s Limahuli Garden & Preserve. No moths were observed serving as pollinators. Alula faces severe challenges to reproduce on its own.

(Content provided by Seana Walsh)

  • Alula
  • Alula
  • Alula
Endangered Hawaiian flowering plant, Brighamia insignis (Alula). All of these pictures are of Brighamia insignis (Alula) in cultivation. Images provided by Seana Walsh at the National Tropical Botanical Garden.
Endangered Hawaiian flowering plant, Brighamia insignis (Alula) in cultivation.
Endangered Hawaiian flowering plant, Brighamia insignis (Alula) in cultivation. Image provided by Seana Walsh at the National Tropical Botanical Garden.
Student rappelling down cliffs to reach plants. Images provided by Ken Wood at the National Tropical Botanical Garden.
Student rappelling down cliffs to reach alula plants. Images provided by Ken Wood at the National Tropical Botanical Garden.
Student rappelling down cliffs to reach plants. Images provided by Ken Wood at the National Tropical Botanical Garden.
Student rappelling down cliffs to reach plants. Images provided by Ken Wood at the National Tropical Botanical Garden.

Student rappelling down cliffs to reach plants. Images provided by Ken Wood at the National Tropical Botanical Garden.

Discover Our Work

  • CPC Rare Plant Academy
  • National Collection
  • Best Practices Guide
  • Pollinator Database
  • California Plant Rescue
  • Florida Plant Rescue
  • Rare Plant Finder
  • CPC National Meeting

Get Involved

  • Donate
  • 40th Anniversary
  • Advocacy
  • Become a Partner
  • Get Newsletters
  • Register
  • Member Payment
  • Underwrite

Meet Our Community

  • CPC Newsletter
  • Institutional Partners
  • Individual Partners
  • CPC Star Awards
  • Fellowships

About

  • Team and Mission
  • Financials
  • Board of Trustees
  • Fellowships
  • Press Room
  • Contact Us

Social Media


The Center For Plant Conservation (CPC) is a 501 (c) (3) non-profit organization (EIN# 22-2527116) dedicated to saving rare plant species from extinction. CPC's National Collection represents more than 2,000 of the world's rarest plants, maintained collectively by its valued network of Participating Institutions.

Center for Plant Conservation National Headquarters 15600 San Pasqual Valley Rd. Escondido, CA 92027-7000

Email: info@saveplants.org; Phone: (760) 796-5686

The CPC National Office is headquartered at the San Diego Zoo Safari Park in Escondidio, California, in partnership with the San Diego Zoo Wildlife Alliance, a CPC Participating Institution.

San Diego Zoo Wildlife Alliance

CPC has achieved the 2019 Gold Seal of Transparency on GuideStar.

Privacy Policy | Terms & Conditions

Copyright 2020 Center for Plant Conservation | All Rights Reserved

FaceBook Twitter Instagram