December 2015

Sneaky Assassin

I found these ants clustered together on my crepe myrtle. What are they and what are they doing? I have tried to identify them but they are not in the “Ants of Brisbane” Queensland Museum Wild Guide. It would be interesting to know, since they look quite spectacular.

Answer

Assassin bug

Interestingly these insects are not ants. They are young Assassin Bugs (Family Reduviidae), recently emerged from their eggs. This is why they are clustered together. The eggs are in the centre of the cluster, and the white objects that you can also see are the caps that the insects removed as they hatched.

Assassin bugs are predatory insects that kill their insect prey by stabbing with their curved, sharp proboscis. They then inject their prey with saliva containing a powerful enzyme. Once their prey’s body contents are liquefied, the Assassin Bug uses the proboscis like a straw to suck up the juices. Assassin bugs sometimes employ those digestive juices defensively, and there are many cases of people being ‘stung’ when the insects have been trapped inside clothing. All agree it is very painful.

Young assassin bugs are called nymphs. They can look quite different from the adults and when in a group such as the one you have photographed can certainly resemble ants. Ant mimicry is known as Myrmecomorphy and has been adopted by many insects and even some spiders.

These nymphs will shortly disperse from your crepe myrtle to look for food and shelter. There are approximately 300 species of Australian assassin bugs in the Family Reduviidae.

For more information visit our Assassin Bugs web page and download our Fact Sheet (244 KB) pdf document icon.

Queensland Museum's Find out about... is proudly supported by the Thyne Reid Foundation and the Tim Fairfax Family Foundation.

Related Links