yucca whipplei
mutualism in the santa lucias:
the story of a small moth with a grand purpose
the tegeticula maculata and its yucca whipplei, or visa versa
PART ONE

seeing a yucca whipplei on a santa lucia night's morning

 by Jack Ellwanger

 

 

 

 

 

 

 

 

 

 

 

they'd been there before
sticking up so grand
dominating the view

but the setting was so much
tan and purple mountains rolling
over and over to the sea

that you didn't really look
at the strange poles of creamy white flowers
so outrageously out of place

not in this soft scene
where mountains and ocean
fuse in endless juxtaposition

santa lucias rising abruptly
sensually from the bright blue pacific

up and down the range
patches of dark green forests
sneak into canyons between mountains
drawing in the ocean's fog to feed upon

between dusky mounds
dark canyons hide creeks
bounding to the sea

all around sage chaparral
gentle quivering little blooms
electrify the eye

in this setting
a stalk of white flowers
from a mexican desert
never looked right

till i saw one at night
looking up from a big sur cove

eyes are drawn to its soft lights
a luminous flower pole glowing in the dark
making the night around it black

but on the ground below
the illuminated flowers glow a circle of light
fuzzy purple chaparral buzzes with life

to see it at night is to have never seen it before

in the morning above the bright blue
on the rising santa lucia mountains
the yucca stands against a huge granite boulder

in the morning it doesn't glow
it shines a creamy wax white
and stands all alone like a signal

splendid regal grand
spanish called it our lord's candle

but its dignity begs for comic relief too
and so they called it quixote's candle
for cervantes' errant knight

peculiar and beautiful it has many names
it reminded the spanish of the tapioca plant in haiti

they also called it their dagger and bayonet

seeing it like it was born last night
those names have purpose

the yucca accents the atmosphere

unusual and singular in flowery splendor
tilting against all odds
it brings attention to the whole picture

it stands so exalted
out of the brown woman thigh hills
that roll over and over to the sea

pointing to the holy trinity
where sea otters are symbiont
with kelp and sea urchins

it waves in a slow gracious flow
along ancient mountains moving groaning
seeping wetness from their purple mountain thighs

past the shimmering granite boulder
tawny kelp rolls in dark blue swells
framing the yucca in gold filagree

the yucca whipplei spanish bayonet points
to the sparkling granite sand beach
where condors once ate whales

it stands like the orchestra leader
not looking like anything else
but bringing harmony

to look at yucca whipplei
when you finally do
is to wonder what it is
how it grows

 
PART TWO

a rare and mysterious relationship

 

in big sur
california rarities
come together in an island

flanked by an ocean and a long river valley
the santa lucias are a refuge of all types
of california rocks plants animals

a funky quixotic plant and a scruffy moth
each with exquisite beauty
and a total dependency on each other
tell a story of nature's most sophisticated coevolution

a little moth less than half an inch
in a night of olfactorial ardor
a very well measured love-making
culminates a strange tale

tegeticula maculata yucca moth
embryos in the yucca whipplei flower
silk threads its larval self down the stalk
and cocoons in the ground

she comes out of the ground looking for bright white waxy
petals of the yucca where it was born as a larva
a male follows her into the flower and they mate

it ate for a whole year for its three night sexual frenzy
she will quickly study and pollinate only
where she needs to

and the yucca plant will accept what it needs
and kill the rest so there is just the right balance
they do it with smells and natural sense

such an almost perfect relationship
40 million years in the making is still evolving
it is so sensible but so mysterious

PART THREE

actual act of ardor

up out of chaparral sage scrub
a moth comes to the yucca at night
on a santa lucia mountain above the sea

at night yucca whipplei flowers open
and glisten with light from the moon
and sends out a smell for the moth to come

in a late winter moonlit night
our lord's candle illuminates the moth's desire

in fluorescent sequence
flowers pop out along the ten foot stalk

out of the ground
and out of the cocoon
male and female moths emerge
looking for bright creamy flowers across the sage chaparral

in lovely yucca petals he fertilizes her
and becomes so exhausted he dies
then she goes to work on the yucca

 

 


Female yucca moth on yucca whipplei pistil pollinating
Photo copyright W.P. Armstrong

 

first she must find a virgin flower
yuccas have two smells
one to attract the moth

another to say she is not a virgin
the moth won't stay in that case
she only has one hundred eggs to lay

in the flower she wags her antennae for scent
if it is a candidate she goes to work
on the dual-sexed yucca whipplei

yucca flowers' female and male parts
are together in the blossom
a low fruiting hermaphrodite

the female moth works from stamen to stigma
collecting sticky pollina and rolling it in a ball
in her maxillary palpi

that is a part of her mouth but under her chin
adapted to mix the male and female yucca pollen
and roll it in a ball which she carries to another flower

with fertilized yucca pollen ball in mouth
she enters the fold of the new flower's petals
and climbs to the top of the pistil

she positions herself on the side of the yucca ovary
with her ovipositor inserted in the ovule chamber
one tegeticula maculata egg is laid

then to carry on the work of pollinating the yucca
she crawls to the top of the ovary and uncoils her palpi
and draws them back and forth across the stigma

now she has successfully pollinated the flower
germinating pollen grains in the tubes will fertilize 300 seeds
of which her larva will only eat 20

yucca whipplei controls how many seeds it will bear
by killing fertilized flowers with too many seeds
it abscises the overly fertilized flower
by shutting off the nutrient flow

that kills all the moth eggs in that flower
and the yucca plant controls how many moths it will produce
keeping a balance for its sustainability

so the moth is grateful for the scent
to tell if the flower had been pollinated
lest its progeny starve

now she marks the yucca flower
that she pollinated with a scent
so others will know to fly on

she only works at night
in the morning she curls up in a yucca flower
and sleeps till the moonlight beckons for the next night's work

 PART FOUR

legacy in a larva

later in the spring
inside the yucca ovule chamber
a tegeticula masculata larva will hatch
and eat some yucca seeds

seeds are stuffed in chambers like a six-shooter
chambers are in columns in the ovary
the moth larva is in one

as it grows in the summer high on the yucca
it fuses seeds in its column with a silk thread 

the moth's larva has become a fat pink worm
and eats the seeds in its column 

it only eats 12 to 20 of the seeds
the rest are for pollination 

in the autumn when the flower is dormant
seed capsules break open
releasing the seeds

except the few remaining
fused by silk thread in the larva's column
where now the fat pink larva has room to roam
and eats the fused seeds and waits 

when the autumn rains come it emerges
and drops to the ground or crawls down the stalk
we don't know which because it has never been recorded 

on the ground it burrows down
makes a silken cocoon with grains of sand
and spends the winter covered with sandy chaparral sage 

PART FIVE

moth emerges and goes to work

with the warm spring rains the yucca whipplei blooms
the yucca moth tegeticula maculata emerges
from the ground and breaks out of the cocoon

it is ready
to conduct such a refined devoted act of reproduction
in such a singular testimony to mutual need
that it must be love 

it immediately looks for yucca flower 

first the male must fertilize the female
so they fly together to a yucca flower
crawl inside the petals and do it
then he dies from exhaustion 

if there has been enough moisture
our lord's candle will begin to flower in february
and keeps it up for months
usually till june

yuccas closer to the sea flower first
they start on the bottom
and pop open in sequence up the stalk in a magnificent inflorescence
each is open only a few days 

at one time flowers all along the stalk
will be in one of all the phases for the whole process
the plant lives four to seven years
the moth lives just a few days

a perfect symbiosis evolved over millions of years
the most rare and sublime we know in the world

 it doesn't exist elsewhere as it does here
with tawny kelp beds framing its creamy flower
or alongside redwoods in a limestone waterfall

after tegeticula maculata pollinates in its three-night frenzy
the yucca seeds will scatter in an autumn wind
and the plant will die

 

 
PART SIX

the historical yucca whipplei

as the climate changed in the mexican mountains
the yucca needed more moisture so it could flower
it migrated here like the great cone trees and madroño

look to the mountains to see yuccas go to the top
along the mountains along the ocean grow
manzanita berries chaparral peas and scrub sage

always somewhere in the middle even when off to the side
a yucca whipplei stands right up ten feet tall with a thousand flowers
out of a huge granite boulder against the dark blue ocean
with a feathery tawny kelp filagree frame around it

from the seed in rocky hillsides yucca whipplei sprang to life
and grew for seven years as a thorny rosette close to the ground

until its time to bloom for reproduction

when it died the native people used it for many purposes
they used the roots for shampoo and the bulb for roasting
it was a community event each family bringing its harvest

along the big sur south coast salinans dug great fire pits
when the coals burned down they added stones
then the yucca roots and more rocks

then built a new fire on top and roasted the yucca for a day or two
they roasted the yucca flower buds and stalks for food
from it too they made a flour for cakes to be stored

the natives used the live yucca too
they made fiber from the stalk and leaves
to weave rope fishing lines nets baskets belts sandals headbands
tie canoes planks together and start fire

to harvest the yucca whipplei without harming it
natives separated the roots from the plant with a wood wedge

just before the yucca flowered
they trimmed the leaves down to close to the base so to get more flowers

it felt like sugar cane and tasted like a baked potato
it could be pounded and made into cakes
dried and stored and used later for stews

much life happens in the santa lucias
of ventana and big sur
yuccas are but a symbol

hundreds of plants find their southernmost
or northernmost home in the santa lucias
sometimes they live alone as a last stand

sometimes in perfect synergy with others
or an oddity that dramatizes the harmony

yuccas came from mexico and went no further north
in the canyon the redwood went no further south
madroños and manzanitas came too from mexico
and live here on bold mountains up from the sea

yucca whipplei and tegeticula maculata
have been studied since 1892 as proof
of darwin's theories of evolution and natural selection
and used to explain mutualism and coevolution

if the moth had not found the yucca
it would have dead-ended most likely
and the yucca needed a pollinator
it tried many allures until the moon worked

they found each other
and evolved to need only each other
they depend entirely and exclusively on each other
and take from each other just what is needed to keep going

never has a moth picked one plant
to be its host and transferring the plant's pollen
particularly with such specific behavior

yuccas can generate rosettes around itself
but these are copies of the parent
and cannot move more than a few feet

in some places a subspecies can send out shoots
underground to produce plants nearby
but these are just copies

yuccas cannot pollinate without the moth
tegeticula maculata has no other function in life
but to pollinate the yucca

it's a perfect relationship that creates a spectacular
symbol of wondrous nature in many places
but hardly so amazing as in coastal santa lucias

by its unusual appearance it brings attention
to the awesome symmetry and synergy of the coastal range
that is the last home to incredible diversity

 

story and yucca photos by jack ellwanger

special editorial assistance by Margie Whitnah

december 2002

SOURCES:

June 1999`Oecologia.'
Vanderbilt University in
Nashville in the June
Oecologia.

Maureen Gilmer
Journal - Gazette Ft. Wayne, Ind.
Mar 17, 2002

Source: The American Naturalist, Nov 1996 v148 n5 p827(21)
Evolution of pollination and mutualism in the Yucca moth lineage.
Olle Pellmyr, John N. Thompson, Jonathan M. Brown and Richard G. Harrison
University of Chicago Press

Ecology, Sept 1997 v78 n6 p1655(6).
Pollinating seed eaters: why is active pollination so rare?
Olle Pellmyr
Ecological Society of America

Susan Milius
Science News Vol 156 1999
National Academy of Sciences of the United
States, August 3, 1999 v96 i16
p9178(6).

Forty million years of mutualism:
evidence for Eocene origin of the yucca-yucca moth association.
Olle Pellmyr and James Leebens-Mack

BioScience, Dec 1995 v45 n11 p741(2).
Moths escape from evolutionary dead end. (coevolution of the yucca plant and yucca moth) (research update from annual meeting of the American Institute of Biological Sciences)

Julie Ann Miller

W.P. Armstrong

Cal Poly Land

CalFlora Database

US Dept. of Agriculture Forest Service Database

Alan Gold, Indian Uses of Desert Plants, Desert USA

Aker, C. L. 1982. Spatial and Temporal Dispersion Patterns of Pollinators and Their Relationship to the Flowering Strategy of Yucca whipplei (Agavaceae). Oecologia 54: 243-252.

Marylee Ramsay and John Richard Schrock
The Kansas School Naturalist, May 1992
Emporia State University and Central States Entomological Society

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