Temognatha heros – Large Jewel Beetle
The genus Temognatha contains the larger Jewel Beetles with the species Temognatha heros being one of the largest. However there are over 85 species with most being endemic to Australia and many of these found only in WA. These beetles are encountered during warm to hot weather, commonly between January and March and often in mallee regions where they emerge from the roots of trees and during a brief mating and feeding spree, lay their eggs around the bowls of trees especially the mallee eucalypts.
The larvae after they hatch, burrow into the roots where they will spend many years feeding and growing (some for over 15 years) to eventually emerge (often en masse) to complete the cycle. It is recorded that in some years, these large beetles can be found not only in huge numbers, but also feeding together in massive mixed colonies. I was very fortunate in mid-February 2013 to happen upon such a mass gathering around Lake Tay (140 km or 85 miles NW of Esperance) where hundreds of beetles from eight different Temognatha species were seen feeding together.
I only saw a single Temognatha heros beetle, but it was enormous easily dwarfing the other large species and upon measuring where it had been on my hand, it was around 8 cm (little over 3”) in length, only bettered in size by a few exceptional beetles of tropical forests. However its large size was not a hindrance to flight, as suddenly it lifted its hardened outer wings (elytra) and with these jockey-like hardened wings held erect, took flight and loudly buzzed off as if powered by an undersized 2-stroke engine.
Temognatha heros occurs throughout most of WA, although in the southern mallee regions, is also recorded across SA into NSW and Victoria.
The genus Temognatha has previously been known as Stigmodera and Themognatha and belongs to the Buprestidae family.
My thanks to Kim Pullen of the Australian National Insect Collection, CSIRO Ecosystem Sciences who kindly confirmed the identity this species.