The second largest order of insects on our planet are moths and butterflies;
order Lepidoptera which is the Greek word for scale and wing. The largest
order of insects is, of course, beetles (order Coleoptera). While known
beetle species number a staggering 350,000 to 400,000, butterflies and
moths follow with about 150,000 species. There are 1200 species of moths
and butterflies in Fiji, most of which are moths.
Moths have long fascinated mankind and are prized by collectors. However,
moth collections, unlike butterflies and other insects, must be kept
out of the light or their colour fades quite rapidly. This makes sense
when one considers that the majority of moth species fly at night without
the need to evolve colours that do not fade in sunlight like butterflies.
Moths, like butterflies, are among nature's most accomplished mimics.
Some moths look like butterflies or wasps. Such adaptation has even
reached the extreme of the European Peppered Moth, which is ordinarily
white to match the bark of the white Birch tree, now in many places
where pollution has covered the White Birch with soot, the European
Peppered Moth has developed a sooty colour to match it. Some moths are
day fliers and would be easily mistaken for butterflies to the untrained
eye.
All
of these adaptations make it very difficult to categorize moths, as
any rule set to distinguish it from butterflies will always have exceptions.
Although many moth larvae are pests to mankind, eating their crop plants
or even clothes, on the other hand, moths and their larvae do benefit
us. Some moth larvae feed on very specific host plants and this has
been well utilised as a biological control agent for weeds. In Australia,
the Witchity Grub, a moth larva, is still an important protein source
to the Aboriginal people. Moths are important pollinators of flowers
and of many fruit crops. And most important in this increasingly crowded
planet of humans, moths are creatures of diverse beauty. The extremely
beautiful Spanish Moon Moth is now threatened and protected by law.
The Ghost Moth of South America has a 300mm wingspan, wider than this
opened bulletin you are now reading.
The
Sphingid (Hawk) Moths are one of the most interesting groups of moths
with their thick bodies and long fore wing, making them quite powerful
flyers. De Havilland probably had Hawk Moths in mind when he named his
very famous "Tiger Moth" biplane. These moths are often called Sphinx
Moths or, because they dart and hover over flowers they take nectar
from, are commonly called Hummingbird Moths. Sphinctid Moths all feed
on blossom nectar through a proboscis that uncurls to reach the bottom
of a flower tube. This proboscis can reach extremes to adapt for specific
flowers. The proboscis of Wallace's Hawk Moth is 35cm long (14 inches)!
Alfred Russell Wallace, an eminent Victorian naturalist and contemporary
of Darwin, guessed a moth must pollinate such a flower and when the
Xanthopan morgani was named, it was also named Praedicta, in honour
of Wallace's prediction.
There
are some 850 species of Hawk Moths worldwide. In Fiji, 10 species have
been described. The larva of some of these species are pests feeding
on crop leaves such as dalo and tobacco but most feed on forest trees
such as Casuarinas (Iron Wood) and Terminalia catappa. Hawk Moths are
found all year round but are most abundant during warmer and wet months.
The
six stamps in this issue feature some of Fiji's most common and visually
exciting Hawk Moths.
