Robust grasshoppers (Brachaspis robustus) look like little grey tanks, short and squat with beautiful grey or rusty red ridges. Their colouring make them hard to spot as they blend in with their surroundings.
They are endangered and normally only found in the open gravel riverbeds of the Mackenzie Basin. However, one of the largest known populations is found on a 3.5km long unused gravel road built during the construction of the Tekapo canal in the 1970s. It’s not know if the population extended naturally from the nearby river or if it established as a result of being moved during the canal construction.
At 38-42mm, adult females are almost twice the size of a male. As a first defence to predators they freeze, which isn’t much help when you are up against predators like mice, rats, stoats, feral cats, hedgehogs and ferrets. Robust grasshoppers are herbivores and they are particularly fond of dandelions.
The lifespan of B robustus is approximately two years. Eggs are laid in summer and they overwinter, often surviving temperatures well below zero, before hatching into nymphs the following summer. The nymphs overwinter to reach maturity the next summer and lay their own eggs.
Photos : Tara Murray, Jennifer Schori
