This page contains pictures and information about Clown Bugs that we found in
the Brisbane area, Queensland, Australia.
- Female, body length 22mm
- There are many common names for the Clown Bugs. They are also known as Coreid Bugs, Gum Tree Bugs,
Sap Sucking Bugs or Squash
Bugs. The adults are reddish brown in colour, with strong and spiny hind legs.
There are many veins on their forewings,
with orange yellow on the wing covers and a sharp angle on each shoulder. Their antennae are four segmented. Their abdomen are long and thin
with greenish-yellow to brown colour on the bottom, bright orange black banded
on the top, covered by wing-covers. They
are slow moving. When disturbed, they move to other side of the leaf. The bug
may eject smelly liquid as defence.
- This is the most common Amorbus species in Brisbane.
As all other bugs in this genus, they feed on shoots of Eucalyptus
trees. Males have shouter hind femora and spiny hind legs. Their nymphs
are variable mixed bright colours.
Male and Female
- Males have shouter hind femora and spiny hind legs.
- Mating pair
Male and female
- The above picture shows the mating couple, from them we can tell their male
and female are looked very similar and about the same size. The picture
shows one bug with its wings broken. Reason is unknown,
anyways, we can see
the bright orange colour and black strips on the top of its abdomen.
- Coreid eggs
- After mating, female lay eggs on host plants. Eggs are laid singly on the leaf surface of shoot tip, several eggs may be
laid close together. The picture above shows some Coreid eggs. We are not
sure what species of coreid lays those eggs, but most coreid eggs look
very similar to these, including this species.
Five Instars Stages
- Their life cycle is one generation per year. In early summer, we easily
found many of them feeding on the young leaves and new shoots on different Gum trees.
After hatching from eggs, Clown Bugs have five immature stages. Different stages instars
are found on
the same Gum tree in early summer. They are in vary colours and patterns.
- 1st instars, body length 8mm, as far as we found, all 1st instars
are same colour patterns.
- Nymphs can be found feeding in clusters on young shoots. After hatching
from eggs, the 1st instars all stay at the new shot of the gum tree and start
feeding. They have powerful sucking mouthparts,
or stylets, which they insert into the plant to suck the sap.
- 2nd instars, body length 10mm
- We noticed
that on the gum tree there are some wilted young shoots. Otherwise the trees
are healthy and seems not affected very much by those bugs.
3rd instars, body length 15mm
- Notice how the wing buds developed in different instars stage.
- 4th instars, body length 18mm
- 5th or last instars, body length 20mm
- The above 3rd picture show
a pale blue nymph become black/yellow after moulting.
- There are the dark blue colour forms as well.
The Smelly Bug
- They are known to produce smelly defensive liquids when disturbed.
We never have this experience from them. Every time when we approach them, we do it
very gently. They seem not so aggressive as another stink
bugs that we found, such as the Bronze Orange Bugs, which ejected the smelly
liquid to us even we are half a meter away.
- In the above first pictures, the small hole between its hind leg and middle leg, is the scent-gland
from which the bug ejects the smelly liquid. The other holes on its abdomen are
the spiracles where air enter the insect body for respiration.
- The above first picture shows an adult with defected wings. The reason of the defect is
unknown. We can see the abdomen colour pattern, which is dark
bands on orange colour, a warning pattern shown when wings are opened.
Why the Clown Bugs have
the strong hind legs?
- Some species in Family Coreidae, including the
Clown Bugs, have their hind legs expanded and somewhat leaf-like. Some of
them are commonly called Leaf Footed Bugs. The bugs cannot jump like
grasshoppers. They do not use their legs to catch other insects like preying
mantids. Their legs seems not effective as a defence weapon. Why the bugs have
their strong hind legs?
- We sometimes found the male bugs standing on the top of
a small plant with one hind leg extended. In the second pictures, one of the
the bug's hind leg is
missing. It did not change it posture even we disturbed.
- From our observations, we believe the bugs' strong
hind legs is the result of sexual selection. The females choose their mates with
stronger hind legs. The males fright with each other with their hind legs.
- We have put two male Clown Bugs together,
sometimes they fright with each other. They hold each other with the front and
middle legs, use their hind legs try to cut the others hind legs. If we inspect
carefully, we can see that the front part of their hind leg is like a saw and
the middle parts of the hind leg form a cutter. We do see a bugs broken his hind
legs after frighting. And the fright was end soon after one loss his hind leg.
- We can predict that a male bug will have the
stronger hind legs. By checking with a number of mating pair, we found that this
is true. And we learn how to tell the gender of a Clown Bugs by looking at its
- This explain why sometimes we can see a Clown Bugs
setting on the plant tip with its hind legs fully extend outwards. This is a
male advertising his hind legs are so strong, or at least have not been broken.
The strong and well shaped hind legs are used as the sign of fitness by the
- This also explain for some species, their hind
legs are over emphasised as board leaf-like.
- This should predict a female will only mate with a
male with two good hind legs. We have observed many mating pairs but cannot have
conclusion yet. We do sometimes find mating pair with single-hind-leg male. We
need more observations on this.
- 1. Insects
of Australia, CSIRO, Division of Entomology, Melbourne University
Press, 2nd Edition 1991, pp 504.
- 2. Specimen
Image Index - Insect Reference Collection Database - ICDB,
Western Australian Department of Agriculture, 2006.
- 3. Insects of Australia and New Zealand - R. J. Tillyard, Angus
& Robertson, Ltd, Sydney, 1926, p147.
Back to top
[ Up ] [ Wingless Coreid Bug ] [ Eucalyptus Tip Bug I ] [ Eucalyptus Tip Bug II ] [ Clown Bug ] [ Wilted-tip-mimicking Squash Bug ] [ Armoured Tip-wilter ] [ Crusader Bug ] [ Large Squash Bug ] [ Fruit-spotting Bug ] [ Cotton Plant Bug ] [ Horned Coreid Bug ]