Beetles and Bugs 5: Lesser Goliath Beetle

M.polyphemus male

Now on show in the newly redecorated Bug World is a pair of Lesser Goliath Beetles Chelorrhina polyphemus. The generic name is a bit uncertain – some authorities now put them in Mecynorrhina. A Cetoniine scarab beetle, they originate from Central Africa rainforest and have a very similar life cycle to the Purple Jewel beetles and Hercules beetles I wrote about in earlier posts.


One of the larger scarab beetles, males of this species can reach nearly 8 cm long, with females around 4cm maximum. Aside from size, the males can be distinguished by the ‘antlers’ on the head, which are not as well developed as those of the Rhinoceros beetle but are still useful in fighting with other males, for which reason males need to be kept separately in captivity.

M.polyphemus female

The adults can live many months, and the complete life cycle from egg to death of adult is around a year, although development time for the larvae is shorter at higher temperatures. Eggs are laid in the soil after the female digs down deep into the substrate, and the larvae feed on decomposing wood, decaying leaves, and anything else with some nutrient content. Although not predatory, they could be cannibalistic if hungry and crowded, and to protect themselves they craft a quite solid cocoon incorporating wood particles before pupating.

Although brightly coloured, the metallic green of their wings is quite effective camouflage amongst rainforest foliage. They are not especially secretive, instead relying on their wings (they are good fliers) and well-armoured bodies to protect themselves. Large beetles like these do not have many predators as adults, although the larvae are favoured foods for many terrestrial mammals and reptiles, and their main threat is probably parasitic wasps, many of which are species-specific, although I have not been able to find much information on what parasitizes this particular species.

In captivity they are slightly harder to raise than the smaller species, but are well within the range of a home hobbyist. Basic rearing conditions are a suitably large container of rotting wood and dead leaves maintained at around 25 degrees for the larvae, supplemented with dry dog food to add nutrients. Adults feed on fruit such as banana, but need a covered container to prevent escape.

For more on raising these and other beetles, see here: http://www.bugnation.co.uk/viewforum.php?f=272

(images from wikipedia)

Beetles and Bugs 4: Fregate Beetle

Fregate Beetle

Growing to around 3cm at the most, compared to other beetles Polposipus herculeanus is not in fact especially large, but still an impressive member of the invertebrate fauna of Fregate island in the Seyechelles. A tenebrionid, it belongs to the same family as the more famous mealworm beetle, but unlike its relative it has a highly restricted range, being known today only from its namesake island.

Beetles and Bugs 2: Big in Japan

D.hercules (male)

The Purple Jewel Beetles I wrote about last week belong to the subfamily Cetoniinae of the Scarabeidae, the scarab beetles. Related to them, but far larger (they include the largest and heaviest of all insects) are the giant Rhinoceros and Stag beetles of the related subfamily Dynastinae. Keeping beetles of all sizes is a popular hobby in Japan, and as a result a surprising number of these magnificent insects are now bred in captivity. The whole group of Rhinoceros beetles all over the world are marked by the extravagant head ornaments of the males, which use their decorations in fights over access to females. Part of the reason they are popular in Japan is that contests are staged between pet beetles like real life versions of Pokemon.

Beetles & Bugs 1: Purple Jewel Beetle

S.africana oertzeni

According to legend, when the great biologist JBS Haldane was once asked what his studies had taught him about God, he replied that he had an inordinate fondness for beetles. There are actually several variants of the quote, largely because JBS repeated the story on numerous occasions (it was too good to throw away). Personally, I take issue with the inordinate part, as beetles represent the largest of all insect groups and have diversified immensely in size, habitat, and lifestyle, with in all probability well over 400,000 different species. Just because people mostly ignore them (unless they eat our crops) is no reason God has to share our prejudice.