The Australian Cockroach
Appearance: The Australian cockroach is a common species of tropical cockroach, with a length of 23–35 mm. It is brown overall, with the tegmina having a conspicuous lateral pale stripe or margin, and the pronotum with a sharply contrasting pale or yellow margin.
Habitat: The Australian cockroach is one of several species of peri-domestic cockroaches (cockroaches that live mostly outdoors, but occasionally may be found indoors) and the most common cockroach species found outdoors in southern Florida. This species resembles the American cockroach but can be distinguished by the presence of light yellow bands on upper margins of the fore-wing.
Eggs: The eggs are deposited into an ootheca (a structure where eggs are held together) with a length of up to 11. The ootheca is attached to and carried by the adult female on the tip of her abdomen and deposited long before the eggs hatch.
Nymphs: Nymphs are wingless, although wing bud structures may be present in later stages. Light-yellow spots on top of the abdomen can be found on the nymphs of the Australian cockroach. This is a characteristic that can distinguish this species from other species of the genus Periplaneta. The nymphs become mottled (spotted or blotchy) gradually as they malt through the five nymphal instars.
It is difficult to distinguish adult male and female Australian cockroaches from the dorsal (top) side. However, characteristics at the tip of the abdomen can be used for discrimination. The adult male cockroach has two pairs of appendages at the tip of the abdomen (a pair of styli and a pair of cerci). However, the adult female has only one pair of appendages in that area (a pair of cerci). Additionally, an abdominal plate (flat structure) projects beyond last true segment of the female.
Life cycle: A complete life cycle of the Australian cockroach includes the eggs, five nymphal instars and the adult. An ootheca may contain 24 embryos, which require about 40 days to complete embryonic development. An adult female can lay about 20-30 ootheca in her lifetime.