of this family are closely related to scarab beetles but can be
distinguished from the later as they have one extra segment (11
in total) on their antennae, and the last 3 segments form a distinctive
circular club. They are very stoutly built beetles and range in
size from 8-30 millimetres in length. Most adults are reddish-brown
to brown in colour, although a few may be black. The head and pronotum
of male geotrupids is often adorned with prominent horns and as
such members of this species are often called rhinoceros beetles.
much is known of the biology of geotrupid beetles and it is thought in
Australia most adults lay their eggs in burrows in the soil and provide
their larvae with decaying organic matter, hypogean fungi or dung to feed
on. Geotrupids are often attracted to lights at night and will often emit
a hissing or chirping sound when disturbed. Both the larvae and adults
are able to produce sound by rubbing parts of their body together.
puncticollis lay their eggs in burrows in clay or sandy soils
and provision the larvae with fungi and/or decaying organic matter.
The burrows of this species are quite distinctive as the entrance
is marked by a push up of dirt which, when fresh is ropey in appearance.
If you find a burrow similar to this with the dirt still fresh
and no visible opening, the beetle is definitely inside. Blackbolbus
puncticollis occurs across Victoria, South Australia and Western
Australia. It is a nocturnal species that is often collected from
lights at night. Blackbolbus puncticollis is able to make
a chirping/grating sound by rubbing their abdomen against a file
on the hind leg.
more geotrupid beetle species visit the Australian
section found here.