- May 7 - Sweadner's (St. Augustine) Hairstreak
- May 21 - 10 Reasons to Like Your Web-Footed Friends (Bats)
- May 23 - Little Bees Make a Big Difference
- June 4 - He Moves in Mysterious Ways
- June 18 - To the Unsung Heroes of Pollination
Off to the
(Moth) Races
Each spring my faithful brugmansia suaveolens (angel’s trumpet) breaks
the soil, green stalk spewing leaves as it races skyward. By June it is six feet tall and covered in a
blush of drooping flowers that unfurl to release their fragrance only at
night. Why the pagentry only when
darkness comes? Considering the brugmansia
is toxic, as are the datura (jimsonweed) and belladonna (deadly nightshade) in
the Solanaceae family, what shadowy creature would nectar on its flowers? Could a visitor actually retrieve the juice
from the base of the brugmansia’s twelve-inch throat?
Enter the Pink winged hawkmoth, agrius cingulata. This member of the Sphingidae family is as lovely
and exotic-looking as the brugmansia flower it visits. There are some beautiful moths, but the hawkmoth’s
sleek wings and tapered body exhibit a geometry that is both stunning and
functional. The name, “hawkmoth”, refers
to its incredible flying capability, achieving speeds up to 12 MPH. Not only are these moths fast, but some are
terrific acrobats, able to hover and flit side to side. The hummingbird hawkmoth is so called because
its wings hum. It can hover and dart like a hummer and it looks like one with a
two-inch wingspan. Its habit of daytime
feeding causes it to often be mistaken for the tiny bird.
But back to a. cingulata, the Pink-winged hawkmoth. Did I mention that it’s pink? Pink and brownish-gray stripes alternate
along its powerful thorax, and blushes of pink hue the lower wings. With a wingspan of 3 ¾” to 4 ¾” and a body like
an oversized Smith & Wesson Special cartridge, it is a sight to see one
hovering under an angel’s trumpet. Not
that I have. But good (or lucky)
photographers have caught agrius cingulata feeding in mid-flight. And those pictures reveal its most impressive
feature: the four-inch proboscis.
Uncoiled, this feeding tube is two times longer than its body. This adaptation, along with its hovering
ability, gives the hawkmoth access to the brugmansia’s nectar.
Hawkmoths, known as sphinxmoths, are nectar experts that specialize in species
with elongated or elaborate flowers, including angel’s trumpet, jimsonweed,
moonflowers, morning glories, and orchids.
The main character in the book, “The Orchid Thief” and movie,
“Adaptation,” tells us that the elusive ghost orchid can only be pollinated by the
Giant sphinxmoth, which has a nine-inch proboscis. Darwin rightly predicted if there’s a flower,
no matter the shape, there’s a pollinator adapted to it.
No matter the toxicity either. Poisonous
trumpet flowers, whose extracts yield belladonna and other opiods have no
effect on these hawkmoths. Mysterious
and alluring, one can understand why trumpet flowers and their symbiont lepidoptera
were often depicted in the arts. A
favorite Victorian theme visualized Shakespeare’s fairy queen from A Midsummer Night’s Dream, Titania,
sleeping under a bower of trumpet flowers while her attendants, Cobweb,
Mustardseed, and Moth frolic nearby.
The
hawkmoth has also found its way into the modern imagination. The creature sealing Jody Foster’s lips in
the poster for “The Silence of the Lambs” is a stylized
Death’s-head hawkmoth. The murderer
buries it’s chrysalis in his victims’ throats.
To understand why it is also called a sphinxmoth, let’s examine
hawkmoth’s “salad days” when it was an ungainly, insanely hungry
caterpillar. The larva has a resting
pose that reminded biologists of the Egyptian sphinx: forelegs extended and head tucked in. Their nickname is “hornworm.” Agrius cingulata spends its youth as a Sweetpotato
hornworm. A voracious pest, it gorges on
sweet potato leaves, morphing from white to green to brown. Its mighty anal horn (helpful in misdirecting
predator attacks) gradually softens and shrinks prior to pupation. Southern farmers have a fulltime job keeping
hornworms from defoliating potatoes, tomatoes, and other crops. Oddly, there have been no a. cingulara citings
of its imago St. Johns County. Our farms
produce large quantities of its host plant.
Who could foresee agrius cingulata becoming handsome, a Chuck Yeager of
the night flyers? The chrysalis hints of
its future beauty: a furrowed amber cocoon
capped by a swirl, it resembles a clasped pendant. The “clasp” is actually the case for the
hawkmoth’s proboscis. A Pink-striped
hawkmoth emerges from its pupa.
But not in my garden. My brugmansia
blossoms beckon nightly. The unsatisfied
blooms soon drop to the ground. If it
has a nectar-loving visitor, it leaves the plant as barren as before. Adaptation enabled the hawkmoth to reach its prize
and survive the feast; it also gave it the “right stuff” to pollinate brugmansia
suavolens: the proper length and shape
to perturb its stamen and transport the pollen to a nearby pistil. In other locales. But not here.
I wonder if agrius. cingulata’s absence is fairy mischief. Perhaps Titania’s heir, inspired by our equestrian
Triple Crown, has summoned her First Coast subjects elsewhere: to attend her nocturnal races. The steed of choice would surely be the
hawkmoth, and I imagine one lucky fairy jockeying in colors of pink and gray. A stellar flyer, it’d be a wings-down favorite. If it found itself racing neck-and-neck in
the home stretch, a. cingulata could magically win by a proboscis.
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