Sunday, September 3, 2017

Beetles and ballet


The tree dance with flowers awaiting pollination. 

Seated with my children on folding chairs at Philo Ridge Farm in Charlotte; strains of Vivaldi pierced the evening air.  There’s nothing quite like live music.  But we were not there just for the music.  A pair of dancers pirouetted onto the ‘stage’, or should I say ‘lawn’.  An expectant hush moved through the audience as the dancers met, and exchanged glances of feigned indifference for the beginning of their performance. Strangely, their gazes seemed focused behind their partner’s backs. 
The performers turned and parted, the side-long view revealing unusual costume choices for classical ballet.  Each had a flickering, glowing, insect-like abdomen extending from beneath beetle-esk wings. This was Farm to Ballet, and we were being treated to ‘The Firefly Dance’.
Perhaps only in Vermont, would a ballet company take to the fields, contributing to the charm that keeps us all here. The dancing was amazing as ballerina and ballerino circled and posed, all the while, each examining the other’s flashing light pattern.  Initially lack of synchrony between their abdominal lights seem to cause repulsion between the dancers.
Real fireflies are innocuous beetles, easily overlooked during daylight hours. Their larvae eat insects and snails and may well be important pest control agents.  They are found in vegetation, leaf litter, and along the soil surface where they are frequently pit trapped by Saint Michael’s College student researchers. 
It is only at night that fireflies come into their own and truly capture the imagination.  The adult beetles use flashing light pulses and larger eyes than those of many beetles to communicate with and attract mates.  Males flash as they fly a few feet off the ground, and choosey females sit in darkness returning the male’s signal only when a particular attractive flash pattern tickles their fancy.  Female fireflies can afford to be picky, at least early in the season when they may well be outnumbered two to one by males.  Mark Branham and Michael Greenfield used computer controlled lights to demonstrate that females of one firefly species really preferred fast flashing males; in fact they responded best to flash patterns that were even faster than most male beetles could ever achieve.
Because fireflies use light to find mates, biologists have frequently expressed concern that light pollution might disrupt their mating habits.  Anyone who has made the mistake of leaving the lights on with a window open can confirm that artificial lights attract insects; entomologists rely on this quirk of insect biology to trap study specimens.  Firefly numbers seem to have declined in recent years as light pollution has increased, but the precise link between fireflies and lights was more clearly established this year when Kevin Costin and April Boulton demonstrated that even a single powerful light placed at a field site could reduce firefly flashing by half. 
If the Farm to Ballet dancers were at all concerned about light pollution, they did not mention it to me.  But creative director Chatch Pregger did confirm my perception of the developing firefly dance.  As he danced with his partner Avi Waring, their lights gradually changed from random, asynchronous flashes, to tightly choreographed patterns that flashed in unison.  The ballerina’s initial distain for her partner was replaced by harmoniously flowing parallel moves and lifts as they simultaneously achieved synchrony of light flashes and choreography that captivated their audience.
According to Pregger, the light flashes controlled remotely by an off-stage cast member were designed to gradually synchronize by the end of the dance.  The synchronous flashing lights mimic the patterns used by the same firefly species studied by Branham and Greenfield.  Females of Photinus consimilis, respond to the males using flash patterns that are dimmer than, but remarkably similar in frequency and duration to those of the males.  If the female sends an appropriate signal to the male, they achieve their own form of highly evolved choreography.
As the evening drew to a close and the crowd filtered out, the subtle sparks of real fireflies continuing their evolutionary journey went largely unnoticed by dancers and audience members.  With summer over, dancers have abandoned the fields in favor their South Burlington Vermont studio.  As the Farm to Ballet troupe develops the following season’s choreography, next year’s firefly larvae have burrowed into the soil following choreography that has sustained them over eons. 

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