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Firefly Nature NotesFirefly Nature Notes
Fireflies and glow-worms are beetles which belong to the family Lampyridae. In fact there are more than 2000 lampyrid species which occur throuhout the temperate and tropical zones, execept in deserts and high mountains. Synchronized rhythmic flashing is only seen in the region stretching from India to the Phillipines and New Guinea.
It is the folded-wing fireflies (Pteroptyx sp.) whuch have developed this striking synchronous flash pattern. The species Pteroptyx tener occurs along tidal reaches of the Selangor river. They may be found singly or in groups ranging in size from a dozen or so, to tree-loads of thousands in estuarine mangrove swamps. Synchronous flashing may not always develop, especially if numbers are low.
Display trees are chosen from species with open foliage (Sonneratia caseolaris, which is known in the Malay language as "Berembang") by the Selangor river. Only certain of these trees are selected. Sonneratia sp. grows on tidal streams or on the coastal areas within the influence of the river. The fruits are edible, but astringent. Commonly associated with Avicennia alba (Api-api hitam). The same display trees may be used over a long period (recorded up to 5 years) and rivermen in Malaysia are said to use firefly trees as navigation marks.
Fireflies develop from eggs and larvae living in the soil or in water. The larvae are carnivourous, probably feeding on nematodes (small round worms),copepods (small shell-less and shrimplike) and midget larvae. Adults live for about one month in captivity, given sugar and water. Male and females are easily distinguished by their light organs.
A few fireflies remain in the display tree by day, but at the Selangor river, most leave the tree at dawn and are found in grass blades and other foliage until one hour before dusk. Flashing begins one hour after sunset at the rate of 3 flashes per second. It takes 15-20 minutes fir flashing to build up from onset to a peak. Only males flash in synchrony. The display is most brilliant during a period of two-three hours after onset, but flashing continues at low levels until half an hour after sunrise. Individuals synchronize by adjusting to previously observed flashing of neighbors, and newcomers quickly develop the synchrony of the tree. Trees which are close together may flash in time.
Males take up flashing stations on leaf edges or leaf points within trees and probably defend the surrounding leaf area. Because the males are spread out, they give the impression of artificial tree lights. They aim their lanterns (to attract females and repel males?) by bending the abdomen downwards; and with the tip nearly touching the leaf, their light is directed forward and laterally. Males may enter into a brief flash dialogue with flying and glowing females, or they may chase after females, both sexes twinkling in flight. Long distance unidirectional flights are made by females possibly seeking sites to lay eggs. On these flights, the fireflies flash about once every 3 seconds.
Why synchrony?
The flash rhythym is species specific and probably attracts females to males from long distances. Further explanation is still controversial. One authority suggests that synchrony within small groups is important, as it attracts more females to the group and therefore to each of the component males. The problem with this explanation is that there is no evidence to suggest that fireflies in display trees make up small groups. The theory also fails to explain why distant groups within the same tree flash together.
Another authority points out that male fireflies probably compete for females by increasing the brightness of their flashes. They suggest that males must flash together in order to let females compare the different flash intensities. Just after a flash, females are less responsive, so a late flash is seen as a dim flash. The problem with this theory is that a clever male firefly which flashed jsut before everyone else would be seen as brighter by a passing female, and would therefore be chosen.
Scientists are clearly having a headache trying to explain why fireflies flash together. See what theories you come up with after viewing this mysterious and beautiful light show.
Back to Malaysia's Fire Fly Farm With Beautiful Fireflies
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