I hiked into Lualualei Valley on the Waianae Coast of Leeward Oahu to explore a patch of mountain ilima that blooms profusely each year after winter storms drench the parched landscape with rain.

Several years ago during a wet and rainy winter, I stumbled on a patch of mountain ilima (Sida fallax) with a prolific bloom of yellow-orange flowers that were irresistable to Kamehameha Butterflies. Since this year’s Kona winter storms brought heavy rainfall to the Waianae Mountains, I returned to explore this ilima patch once more.

The back of the Waianae Valley is exceptionally green and lush due to heavy rains in the past 6 weeks. In the summer months when rain is scarce the landscape will change from green to yellow to golden-brown.

Interspersed among kiawe trees and tall grasses are patches of mountain ilima 4-5 feet high which produce flowers by the hundreds after the winter rains.

Ilima is indigenous to the Hawaiian Islands. Ilima is a polymorphous species that varies greatly in height, habit, leaf size shape, and flower color.

The beach form of ilima assumes a crawling prostrate form, known as “ilima papa”, no more than 6 to 12 inches off the ground. Mountain ilima assumes the form of a shrub, known as “ilima kuahiwi”, usually about 4 to 5 feet high but can grow up to 10 feet high.

During the rainy season, ilima produces large clusters of flower buds which are choreoographed to open a handful at a time every day over the course of several weeks.

Ilima flowers are tissue paper thin — they are fragile, bruise easily, and last for only a single day.

You can watch ilima flower buds open-up into charming yellow-orange flowers if you arrive early enough in the morning.

Over the course of 2 hours, the buds open up into charming flowers about half-an-inch across. The 8 time-lapsed photos in this series were taken about 15 minutes apart.

Since ilima flowers are the color of the ruling class in old Hawaii, ilima flowers were fashioned into leis reserved for the ali’i (chiefs). Ilima flowers were also used in a number of medicinal preparations to treat a range of ailments.

One of the first creatures to visit ilima flowers are hover flies (Simosyrphus grandicornis), which are not native to Hawaii. Hover flies have large heads, large eyes, clear wings and an abdomen striped in and black and yellow.

Hover flies look and act just like bees and are also important pollinators in the native forest. Hover flies have a very characteristic flight pattern — hovering in one spot, moving suddenly forwards or sideways, then hovering again — hence, their name. Hover flies are are so small and light, that they are one of the few insects who who do not bruise ilima flowers when they landed on its petals.

While photographing ilima flowers I saw a number of blue damselfies, known as the “Familiar Bluet” (Enallagma civile), in the grass on the margins of the ilima patch waiting for unsuspecting prey. This damselfly is an introduced species that is not native to Hawaii.

Damselfies are agile fliers and can catch hover flies in mid-air. This Familiar Bluet damselfy rests on a sprig of ilima as it eats a hover fly.

The grasslands surrounding the ilima patch are prime mating grounds for damselfies. A blue male grasps a gray female just behind the head with a forceps-like structure at the very tip of his abdomen. When the female is ready, she curls her abdomen to attach with the male to consumate the pairing.

Life comes full circle in the ilima patch as predator becomes prey. I stood transfixed watching a small spider catch and overcome a much larger blue damselfly.

Honey bees (Apis millifera) arrive in droves and buzz from flower to flower collecting nectar and pollen. Ilima flowers are so delicate that their petals cannot support the weight of bees. A single bee landing on the flower will bend and bruise the tissue-paper thin petals.

Ilima flowers also attract Gulf Fritillary Butterflies (Agraulis vanillae), a bright orange butterfly with a striking iridescent pattern on the underside of its wings.

While Gulf Fritillary Butterflies are not native to Hawaii, they have become important pollenators in the native forest. Unlike my last visit to this ilima patch, I did not see a single Kamehameha Butterfly nor any other native insect during my 3 hour visit.

While I was disappointed that native insects were no where to be found, I was pleased that introduced insects are pollenating and perpetuating this patch of native flowers. I also pleased to have witnessed the captivating life and death drama that happens every day in this small little patch of mountain ilima in Waianae.

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SOURCES

Damselfy Researcher — Joshua S Rose – Website

Gulf Fritillary, Wikipedia

Hawaiian Native Plant Propagation Database

Hawaiian Ethobotany Online Database

Hover Fly – Simosyrphus grandicornis

Hover Fly Fact Sheet

