Family Scarabaeidae - Chelorrhina polyphemus

Chelorrhina polyphemus
Size: 50 - 70 mm
Range: central equatorial Africa

Chelorrhina polyphemus is a large African member of the scarab subfamily cetoniinae. There are several distinct varieties within the species: C. polyphemus polyphemus, C. polyphemus confluens, and C. polyphemus rufino. The only other member of the genus Chelorrhina is C. savagei of Zaire, which is rather similar in appearance. Chelorrhina is an inhabitant of dense tropical forest, and like other members of the cetoniine scarab group, they can frequently be seen feeding at sap flows on wounded trees. The larvae reside in the compost which forms inside decomposing logs. The colouration and patterning of the thoracic shield or "pronotum" in Chelorrhina is somewhat similar to that of the related genus Goliathus. C. polyphemus has been portrayed a number of times on postage stamps issued by several central African nations.

A male Chelorrhina polyphemus. Some have horns considerably longer than those of others. Unlike the dynastines, many species of cetoniine scarabs do not possess horns, but Chelorrhina, Goliathus, and a number of other genera are exceptions. Chelorrhina larvae are known to sometimes be cannibalistic, but can be reared together in the same container so long as they are provided with adequate food and space. In addition to composted leaves and wood, Chelorrhina larvae also thrive on slices of apple buried in their substrate occasionally. Such supplements will help to ensure large, healthy adult beetles with good horn development.

Photo courtesy of Fan Lin.

Chelorrhina polyphemus (male) - Image © Fan Lin

Chelorrhina polyphemus (male) - Image © Roman Kocina

This male exhibits a somewhat longer horn than the individual pictured above. Note the presence of cepahlic side horns in this species. Though not apparent in this photograph, the side horns actually have "scalloped" edges composed of many small tooth-like projections. Horn design and size is largely influenced by the quality and quantity of food that the insect consumed as a larva. Obviously, large larvae transform into large adult beetles, and larvae which are small and stunted due to a lack of proper nutrition produce adults which are smaller than average and have underdeveloped, short horns.

Photo courtesy of Roman Kocina.

The female C. polyphemus. Her markings are very similar to those of the male, but she has a more shiny surface texture, and is without horns. Females of this species sometimes approach the size of males if well fed.

Photo courtesy of Milan Polaczyk.

Chelorrhina polyphemus (female) - Image © Milan Polaczyk

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