A possible trigger for this could be if individuals are put under a large amount of stress from harmful local conditions during the final instar.

Phaulacridium marginale exhibits colour polymorphism with two basic patterns: striped and unstriped.

Of the two New Zealand species, Phaulacridium otagoense is endemic to the South Island (Mackenzie Basin and Central Otago).

Although it has not been reported as a dominant diet component, it has been found in the gizzards of black-billed gulls (Larus bulleri), starlings (Sturnus vulgaris), Australian magpies (Gymnorhina tibicen), and New Zealand pipits (Anthus novaeseelandiae).

[11][12] Phaulacridium marginale has also been reported in the diet of two invasive mammal species, European hedgehogs (Erinaceus europaeus)[13] and common brushtail possums (Trichosurus vulpecula).

[14] It has been noted that an unknown species of parasitic horsehair worm (Nematomorpha); Gordioida) was found in one collected specimen of Phaulacridium marginale.