makes it extremely distinctive. If you see one, you’ll
recognize it. Females are similar to males in size but lack
the long horns, a characteristic true of all scarabs. The
Hercules Beetle (Dynastes hercules) of Central America
is similar but even larger, reaching lengths of 17 cm (6.7
in). Its long horns project forward, unlike those of the
Rhinoceros Beetle, which curve upward.
Charles Darwin (1871) hypothesized that these
large male scarab beetles evolved their horns by sexual
selection (chapter 10). The horns, thought Darwin,
would aid the males in combat for female scarabs. Males
do use the horns in combat. Scarabs and stag beetles all
over the world, from Costa Rica to Africa to the Solomon
Islands, jostle like wrestlers, locking horns until the victor
lifts the loser and tosses him out of the tree. What is not
abundantly clear is the degree to which females care about
all this pugilism. Males seem more oriented to fighting for
favored feeding sites in the trees than for females. Females
may “care” about the battles insofar as victorious males
have access to good sources of nutrition. From a female’s
viewpoint, these would be the males to get to know.
There are many scarab species in the Neotropics, most
very beautiful. Some species, such as those in the genus
Megasoma, require mature lowland rain forest, because
the larvae must live in large decaying logs. The cutting
of rain forest and the conversion from forest to brushy
areas may significantly reduce the beetle’s reproductive
success. Already Megasoma are considered to be rare in
many places.
Lantern Fly (Peanut- headed Bug)
The remarkable Lantern Fly, or Peanut- headed Bug
(Fulgora laternaria; plate 16- 95), is really worth seeing. It
is large, with a 12.5 cm (5 in) wingspan, and when oriented
vertically along a tree trunk vaguely resembles a lizard.
The reason for the resemblance is its long head, whose
shape and markings make it look like a cross between
a lizard head and an alligator head. One Spanish name
for it is mariposa caiman, meaning “alligator butterfly.”
A member of the Homoptera, or sucking insects, the
Lantern Fly is unusual in almost every way. The English
name Lantern Fly comes from the mistaken belief that the
huge head is bioluminescent (able to glow in the dark). It
isn’t. Its alternative common name, is Peanut- headed Bug,
another reference to the odd shape of its head.
The Lantern Fly comes equipped with several survival
strategies. When oriented on a tree trunk, it is highly
cryptic, its soft mottled grays making it appear as part
of the bark. If disturbed, it will climb away or drum
its head against the tree, making a rapping sound. If
the disturbance persists, the insect discharges a skunky
odor and flies to another tree. When it takes flight, it
reveals bright yellow eyespots on its hind wings, rather
like those of the Owl Butterfly (discussed below). These
spots, which may also be revealed by a quick flash of
the wings when the animal is not in flight, may act to
temporarily confuse a would- be predator.A Lepidopteran Sampler
In this section are some noteworthy butterflies and
moths (order Lepidoptera) that almost every visitor to
the lowland rain forests notices.
I’ve previously discussed the butterflies of the genus
Heliconius (plate 16- 96), their relationship with plants
of the genus Passiflora, and their mimicry complexes
(chapter 11).Plate 16- 95. A Lantern Fly with its wings open, showing its
distinctive eyespots. Photo by James Adams.
Plate 16- 96. Heliconius butterflies shine like beacons in the
forest understory. Photo by John Kricher.360 chapter 16 from monkeys to tarantulas: endless eccentricities