Rhinoceros Beetles

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Scientific name

Oryctes rhinoceros L. and Oryctes nasicornis L.

Family

Family Scarabaeidae, Subfamily Dynastinae

Description

Rhinoceros beetles are a subfamily of beetles that are among the largest-bodied beetles, ranging from 30-60 mm. Their common name is derived from the characteristic cephalic horn, which is usually considerably larger in males. The adults are black or dark brown, often reddish, with velvety reddish-brown pubescence on the ventral surface. The female O. rhinoceros also has these hairs on the pygidium, which can help distinguish her from the male. Females lay 70-140 small eggs (3-4 mm long) in decaying wood, and the larvae hatch around 12 days later. The larvae are large (60-105 mm), white, and C-shaped, with legs and a brown head capsule. They feed on the rotting wood, and develop for 72-130 days before pupating. The imago, or adult, usually emerges after around 20 days. In Oryctes beetles, it is usually the young imago rather than the larva that causes damage by boring the crowns of healthy palms.

Diagnostic features

Rhinoceros beetles are easily recognizable due to their large size and characteristic rear-facing horn on the top of the head, though the horn is reduced in females.

Distribution

Oryctes rhinoceros is native to south and southeast Asia, but has been introduced throughout Asia and the western Pacific.

Oryctes nasicornis is native to Europe, North Africa, and part of Central Asia.

Hosts

Oryctes rhinoceros

Palms: Cocos nucifera (coconut palm), Elaeis guineensis (African oil palm), Phoenix dactylifera (date palm), and a variety of other ornamental palms, including Wodyetia bifurcata (foxtail palm)

Other: pineapple, sugar cane, Pandanus, and banana

Oryctes nasicornis may occur on a variety of palms and other species.

Additional comments

Oryctes rhinoceros is one of the most damaging pests to coconut and African oil palms wherever it occurs.

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