Insect of the week – Cockroach

A face only a rugby league player could love.

By Kim Pullen Australian National Insect Collection

(Inspired by New South Wales’ (nickname the Cockroaches) win in State of Origin this week)

We love to hate cockroaches. They scuttle across the floor when we turn the light on, and leave stains in kitchen cupboards. They seem to thrive in the foulest places.

But the few familiar kinds that disgust us only give a bad name to the numerous other blameless kinds of cockroaches – hundreds of native species in Australia alone – that go about their business unobtrusively, recycling all manner of organic material.

Like their introduced pest cousins, most native cockroaches are nocturnal; during the day they hide under leaf litter or bits of bark, or in burrows they make in rotten wood or in the soil.

A few species do come out during the day, and some of these are actually quite colourful – Mitchell’s Cockroach (Polyzosteria mitchelli), blue with yellow stripes, adorns drab desert plains, and the Alpine Metallic Cockroach (Polyzosteria viridissima – its name means very green) – suns itself on bushes in plain sight.

On the left, a benign and wingless native bush cockroach (Polyzosteria limbata), a female carrying an egg case attached to her rear. On the right, an introduced pest cockroach (Periplaneta brunnea), with its overlapping wings covering the abdomen.

Would you like to keep a pet cockroach? Australia is home to the Giant Burrowing Cockroach (Macropanesthia rhinoceros), the world’s heaviest. These monsters, 80mm long and up to 35g in weight, rear their babies on dead gum leaves that they drag into metre-deep burrows in sandy soil in northern Queensland. They make good pets!