Comprised of fifteen Australian species. Only a single species is found in Tasmania. DNA evidence shows it is endemic to the state and the populations which range from coastal to alpine habitats are genetically indistinct. They are found mostly in the central highlands, but also about 30% of the time around the east coast. Even detailed DNA analysis has shown these to be identical species so how the populations are linked is still a bit of a mystery.
They are also known to host “Gordian worms” (Nematomopha: Gordioida), commonly called horsehair worms. Cockroaches parasitised by horsehair worms may be observed in mass death events on Central Highland lake shores. A relationship with water may also explain how specimens reach the coast, via downstream rafting? but observations which link the alpine and coastal populations are lacking. We wonder if they float downstream? This could be supported or complicated by the findings of Richards & Spencer (2019) -that they are also parasitised by gordian worms which leads to mass ‘strandings’ at the waters edge of the central lakes.
Mid March 2008
Lake Augusta, Central Highlands
Images by James Wood, used with permission.
Identification and information thanks to Shasta Henry.
Late December 2010
Talinah Lagoon, Central Plateau
Feeding on Orites revoluta flowers.
Image by James Wood, used with permission. Identification thanks to Shasta Henry.
Henry, Shasta & Cameron, Stephen & SMOLENSKI, ADAM & Mcquillan, Peter. (2021). Polyzosteria cockroaches in Tasmania (Blattodea: Blattidae: Polyzosteriinae) represent a new, endemic species, with allopatric alpine and coastal sub-populations. Zootaxa. 4926. 384-400. 10.11646/zootaxa.4926.3.4.
Richards, Karen & Spencer, Chris. (2019). Notes on the ecology of the Tasmanian alpine cockroach Polyzosteria sp. Burmeister, 1838 (Blattodea: Polyzosteriinae) including parasitism by Gordian worms (Nematomorpha: Gordioida). 141. 27-33.