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RHINOCEROS BEETLES

SCARABAEIDAE: DYNASTINAE

T

he subfamily Dynastinae, known as the

rhinoceros beetles, is a medium-sized group

of between 1,000 and 2,000 species. The males are

often ornamented with extravagant horns, hence

the name “rhinoceros.” These horns serve a similar

function to a peacock’s tail, as they are used for

mating displays and signaling, but they are also

used, like the antlers of stags (or stag beetles), for

fighting with other males for control of the

unornamented female, which is usually in the

nearby foliage awaiting the outcome of the battle.

In spite of these huge appendages, almost all

rhinoceros beetles are able to fly (even though they

are not especially elegant!). They may fly noisily

around street lamps and other light sources on hot

tropical nights, but only when the temperature and

humidity reach certain levels.

Rhinoceros beetles include the heaviest of all

beetles (a larva of the Central American Actaeon

Beetle Megasoma actaeon has been weighed at

7 ounces/200 g, about the same as a hamster).

These massive white grubs feed in humus-rich

SCARABAEIDAE: DYNASTINAE

subfamily

Dynastinae

known species

1,500

distribution

Warm places, tropics, and subtropics.

Rare or absent in temperate countries

habitat

Forests, anywhere where there is an

available supply of decaying plant matter

such as wood mold or compost for

development, even in and around tropical

cities in parks and gardens

size

1–19 cm

diet

Larvae eat decaying plant matter such

as wood mold, sawdust, compost, and

humus-rich soil. Adults may feed on sweet

sap or nectar but in many cases do not

feed at all

left | Chalcosoma moellenkampi

A male Bornean Atlas Beetle, or

Three-Horned Rhino Beetle, the largest

beetle on the island of Borneo.