162
WILLIAM MACNAE
trees of 8. caseolaris were chosen for the display on the banks of the
rivers below Bangkok and below Kuching. This tree has an open
willow-like foliage of broad leaves, always quivering in the slightest
breeze. Fireflies displaying on such leaves will be clearly visible to
others flying past. The firefly trees could be distinguished both by
night and by day from distances of 100 m or so, again evidence of a
clear view. Tall trees of some 15-20 m contained some fireflies. It was
noticed a t Lob0 Kara in the Sarawak river delta that synchronous
displays were taking place in the canopy of trees of Rhizophora apiculata,
and again oiily of selected trees. The most spectacular displays seen
were in small trees some 3-4 m high. Flashes were emitted as the
A
B
FIG. 46. Photometer records of successive flashes of fireflies. A. Three successive flashes
of a male Pteroptya sp., the period is 0.52 sec; note that each flash is double.
H. Three successive flashes of a female Pteroptyz sp. C. Fifteen successive flashes
of an undet,ermined number of males in an Acan,th,us bush. (Figs. 1, 3, 6, of Buck,
1968.)
fireflies ran over either surface of a leaf and were intense enough to be
visible through the leaf.
According to Buck and Buck (1966, 1968) and to Polunin (personal
communication) flashes are given out in two distinct synchronous
rhythms. One is a rapid series of flashes a t around half-second intervals
(Fig. 46); the other noticeably slower. The rapid flash comes from a
firefly of 5-6 mm long, and the slower flash from a larger one of 8-10 mm.
Later in the evening stationary dull glows become visible and these
may be seen t o come from copulating pairs (Fig. 47).
The synchrony was not noticed on three nights spent in the Bako
National Park in Sarawak. A group of four trees, two of Avicennia
marina and two of Bonneratia alba, were chosen for display but no
synchrony had been established by 22.00 h. This, in fact, was one of
the localities visited by Buck and he reported that synchronous
flashing has been recorded here, but he saw no synchrony. At the time
of my visit in January there were few fireflies in the trees; this would
WILLIAM MACNAE
trees of 8. caseolaris were chosen for the display on the banks of the
rivers below Bangkok and below Kuching. This tree has an open
willow-like foliage of broad leaves, always quivering in the slightest
breeze. Fireflies displaying on such leaves will be clearly visible to
others flying past. The firefly trees could be distinguished both by
night and by day from distances of 100 m or so, again evidence of a
clear view. Tall trees of some 15-20 m contained some fireflies. It was
noticed a t Lob0 Kara in the Sarawak river delta that synchronous
displays were taking place in the canopy of trees of Rhizophora apiculata,
and again oiily of selected trees. The most spectacular displays seen
were in small trees some 3-4 m high. Flashes were emitted as the
A
B
FIG. 46. Photometer records of successive flashes of fireflies. A. Three successive flashes
of a male Pteroptya sp., the period is 0.52 sec; note that each flash is double.
H. Three successive flashes of a female Pteroptyz sp. C. Fifteen successive flashes
of an undet,ermined number of males in an Acan,th,us bush. (Figs. 1, 3, 6, of Buck,
1968.)
fireflies ran over either surface of a leaf and were intense enough to be
visible through the leaf.
According to Buck and Buck (1966, 1968) and to Polunin (personal
communication) flashes are given out in two distinct synchronous
rhythms. One is a rapid series of flashes a t around half-second intervals
(Fig. 46); the other noticeably slower. The rapid flash comes from a
firefly of 5-6 mm long, and the slower flash from a larger one of 8-10 mm.
Later in the evening stationary dull glows become visible and these
may be seen t o come from copulating pairs (Fig. 47).
The synchrony was not noticed on three nights spent in the Bako
National Park in Sarawak. A group of four trees, two of Avicennia
marina and two of Bonneratia alba, were chosen for display but no
synchrony had been established by 22.00 h. This, in fact, was one of
the localities visited by Buck and he reported that synchronous
flashing has been recorded here, but he saw no synchrony. At the time
of my visit in January there were few fireflies in the trees; this would