Hawaii National Park is rich in insect life although, as is typical of
insular areas, insects are much more sparse than in continental regions.
Most of our insects are endemic species, i.e., are found only in these
islands; many are very limited in distribution. For the most part the
endemic insects are associated with the native plants. Most of our
insects are comparatively small and inconspicuous; nevertheless, a great
many are strange and unusual so that our fauna is particularly
interesting to the scientist. We have none of the larger, showy
butterflies and other insects which the visitor often expects to find
here. No noxious or harmful species are present in areas used by park
visitors, but the large blowflies which breed in goat carcasses in
Haleakala Crater sometimes become a nuisance, due to their presence in
large numbers. These are mainland species which have been accidentally
introduced into Hawaii and which are now restricted to the highland
areas where the climate is temperate. With the exception of lice and
domestic flies, which were brought here by the Hawaiians themselves,
Hawaii was free of pestiferous insects before the arrival of the
Europeans.
One of the best known endemic Hawaiian insects is the butterfly named
after King Kamehameha, _Vanessa tameamea_, a highly colored relative of
the painted lady, the tortoise shells, and the red admiral butterflies
of the mainland. This species is highly prized by amateur butterfly
collectors since it is found no place else in the world. Its colors are
orange, brown, and black. The female has small white spots in the apical
portions of the front wings; these spots are rosy colored in the male.
The caterpillars, green or purplish, feed on the leaves of the _mamaki_.
Adults are found in forests throughout the islands. They are attracted
to the native hydrangea, _kanawao_, to the introduced thimbleberry, or
to the sap exuding from _koa_ or _naio_. This butterfly is a strong
flier, and ranges from the seacoast to the top of Haleakala. The female
of _Hodegia apetala_, an endemic genus of only one described species, is
an Hawaiian moth unable to fly.[22] The male is unknown. This jumping
insect, related to the bollworm, lives in bunch grass near the summit.
The narrow, pointed, reduced, ashen-brown wings are ½ inch long; the
abdomen, about as long as the wings, is brownish gray.
As one walks over open patches at higher elevations a brown moth, 1½
inches wide, rises readily before one. This is _Agrotis aulacias_ that
possesses great powers of flight.[23] The genus of 27 species is related
to army worms, cut-worms, and a host of agricultural pests. _Fletcherana
insularis_ is a geometrid moth (inch worm, measuring worm, or looper)
found in late spring high above the forest belt near the park entrance.
The insect is an inch wide, its color is white, speckled with black. The
genus of 5 species is confined to Hawaii.
_Nesophrosyne haleakala_ is a mottled, gray-brown leafhopper, 1/8 inch
long; the head and front part of the thorax are yellowish. In the park
it is found in _pilo_ and _ohelo_ at 8,500 or 9,000 feet. The genus is
endemic and contains over 60 forms distributed throughout the islands.
An undesirable pest has publicized its presence high above the park
entrance by leaving its name on two caves which early visitors found
convenient for shelter. Big Flea and Little Flea Caves often appear in
accounts of early trips, but never without mention of the annoyance that
was caused by their permanent occupants. Of the 7 different kinds of
fleas recorded for Hawaii, only the so-called cat flea (_Ctenocephalides
felis_) annoys people to any extent. Several species of fleas infest the
Hawaiian rat and were presumably brought in when this rodent arrived
with the earliest Polynesian immigrants.
Because the beautiful silversword has no very close relatives, which
means that its ancestors arrived in Hawaii in earliest time, any species
of insects associated solely with it as a host plant draws particular
interest. Moreover, since the survival of silverswords is precarious in
this day of rapid change, all agents that threaten must be carefully
scrutinized. Silverswords are specific hosts to a half dozen or more
endemic species of insects.[24] Among Lepidoptera, the family of moths
and butterflies, the larvae of a pyralid moth, _Rhynchephestia
rhabdotus_, feeds in the flower-heads, destroying the seeds.
Caterpillars of a noctuid, _Euxoa epicremma_, have been collected
beneath plants. The caterpillars of a tineid moth have been found among
dead leaves. Of the DIPTERA, great numbers of yellow maggots of a gray
fly, _Tephritis cratericola_, feed on the seeds and prevent their
development. The larvae of one of the Coleoptera, a beetle described as
_Aescheithmysus terryi_, feeds apparently only on old and dead stems. A
relative, _A. swezeyi_, similarly feeds on _Railliardia_. Great members
of a leaf-hopper, _Iburnia argyroxiphii_, suck the sap of Haleakala
silverswords. It is preyed upon by a wasp, _Polynema sp._, so tiny that
the naked eye can hardly see it. The wasp lays its egg in the egg of the
hopper. The larval wasp, upon hatching, feeds on the contents of the
hopper egg, pupates within it, and emerges from it.
The Paliku area is very rich in insect life; many hundreds of species
have been recorded from here and many are apparently very restricted in
distribution and are known only from this locality. Species of
pomace-flies (DROSOPHILIDAE) and the long-legged flies (DOLICHOPODIDAE)
are especially prevalent at Paliku. Two species of the native genus
_Idiomyia_ are the largest members of DROSOPHILIDAE found any place in
the world; they measure approximately 7 mm. in length. Two species of
flightless Neuroptera (_Pseudopsectra cookeorum_ and _lobipennis_) occur
on the vegetation (_Dubautia_, _Metrosideros_, and _Cyanea_) in
Haleakala; these represent one of the strangest entomological
curiosities of the world.
Over five thousand species of insects have been recorded from the
Hawaiian Islands and it is probable that several thousand more species
remain to be described. In the past our knowledge of the insects was
based largely upon the monumental study, "Fauna Hawaiiensis,"[25]
published by a group of institutions including the British Museum
(Natural History) and the Bernice P. Bishop Museum. A new faunistic
study is now under way titled "Insects of Hawaii."[26] This is an
extremely valuable reference work and is indispensable to anyone
studying Hawaiian insects. It gives a complete review of the insects
from the lowest orders through the butterflies and larger moths. Two
volumes on the DIPTERA are now in press. Volume one gives a most
comprehensive account of the mode of dispersal of our endemic fauna and
flora to these islands. It is estimated that the 3,722 known endemic
insects developed from approximately 250 ancestral species.