National Geographic : 1962 Jul
KODACHROMES (C NATIONAL GEOGRAPHICSOCIETY to see fireflies twinkling from every twig and leaf the minute I arrived. "We've got to have more rain or night humidity before you'll see them out en masse." Why do fireflies fill the summer evenings with their myriad bursts of light? The flashes, I knew, are simply courtship signals, a means of finding a mate in the darkness. Adult fire flies live only a few days, or at the most a few weeks, their sole function being to propagate. Adults of most species, it is believed, eat no food at all. Once mating is done and a new generation of eggs has been deposited in moist crannies, nature has no further need for her bits of wing-borne star dust, and they die. Tom advised that flying adults would prob ably best be found this time of year-early summer-in Jamaica's wetter highlands. Ac cordingly, my sights narrowed on the Blue Mountains northeast of Kingston. From coastal lowlands I drove up increas ingly steep slopes and crept around hairpin turns to the cliffside home of Doris and Inez Sibley, daughters of a missionary and stu dents of Jamaica's flora and fauna. There, amid a mist-nurtured forest, 22 miles by 50 Shown actual size, two Jamaican fireflies of the species Photinus pal lens rest in a leafy retreat by day. Feeling its way with sensitive antennae, a fire fly climbs a blossom in the author's laboratory. Hatlike pronotum shields the insect's bulging eyes. Photinus pallens, here magnified ten times, is one of Jamaica's most plentiful luminous insects. Despite their name, fireflies are actually beetles. They spend as much as two years in or on the ground as larvae, pupating and emerging only to mate, lay eggs, and die. Though they have mouths, adults of some species are believed never to eat. road from the sea, I rented a combination workroom-bedroom to serve as center of my operations. My window looked out on crags that rose nearly a mile above the coastal plain, their rugged sides blanketed with jun gle and interlaced with streams (page 52). Each evening shortly after sundown I would station myself at the edge of a ravine not far from the Sibley place. As night closed in, the performance would begin-a hesitant flash here, an emphatic one there, then a few more, building gradually, especially when the sky was moonless and the stars were hidden by overcast, to a brilliance that filled the air and spangled the foliage. One almost ex pected to hear muted strains from Mendels sohn's A Midsummer Night's Dream overture wafting through the curtain of darkness. But here, accompanying nature's pyrotech nics, were no sounds-only stillness, a still ness from which struggle and death were never far removed. Silken Thread Binds Doomed Firefly Once, as I waited, my eyes perceived a cu riously unwavering point of light somewhere in the gloom ahead. Flashlight in hand, I in vestigated. I found a firefly, its lamp con tinuously aglow, entangled in the web of a yellow-and-black spider the size of an almond. Six of the spider's feet clung to the web while its other two legs rotated the hapless firefly. Simultaneously, the captor emitted a silken thread that bound the spinning victim in an ever-tightening coil. Even when en shroudment was nearly complete, the firefly's lantern still gleamed brightly-as if hopeful, to the end, of attracting a rescuer (page 56).