Muehlenbeckia astonii - food and shelter for a New Zealand katydid

I have written before about Muehlenbeckia astonii - one of a number of our native plants which has a divaricating pattern of growth where the repeated branching of the stems at wide angles creates a zig-zag thicket.  It is a wonderfully weird looking tangle of a shrub with wiry coppery brown branchlets, tiny heart-shaped leaves and little starry white flowers.  It is deciduous, so perhaps it was an autumnal thinning of the little leaves that allowed me to recently see something I had not noticed before...

A katydid! 

At first it was barely visible, although it is clear enough in this relatively close shot.  In fact, I counted eight katydids dotted amidst the shrub.  But they were so well hidden that you couldn't see them readily in photographs which I took from the distance required to include them all. 

This was a surprise.  Katydids are very good at munching their way through various introduced plants - my roses have been a prime target.  I have regarded them as attractive but a pest.  I hadn't even thought that the katydids I see in the garden might be native insects.  But Caedicia simplex, to give the proper name, is a New Zealander belonging to the family Tettigoniidae which numbers more than 6,400 species and is found on all continents except Antarctica.  The Maori name, I have learned, is Kiki Pounamu. 

Excellent camouflage is a feature of many katydid species.  Somehow, despite its size, the angular legs of this katydid blended with the angles of the branches, and the bright green leaf-like body (very well hidden on rose plants) blended with the massed effect of tiny green leaves.  The shrub offered added protection - a protective zig-zag wall.  I couldn't reach any of them. 

If finding it on the Muehlenbeckia was a surprise, the behaviour of the katydid was not.

Eating!  Not a pleasing sight, even if it does look very pretty with the backlight emphasising the patterns on its wings and exoskeleton. 

A closer crop shows this more clearly.

One theory about divarication is that it was an adaptation to protect leaves from the moa, an extinct very large plant eating flightless bird.  However, it is thought more likely that divarication evolved in response to harsh weather conditions, protecting the plant against desiccation and wind damage - Muehlenbeckia astonii is a tough coastal plant.  But the divarication and tiny leaves are no protection against small plant eaters.  In my reading this plant was described as an important host for insects, which in turn become fodder for native birds and lizards.  And deep-rooted Muehlenbeckia astonii can outlive them all - up to 80 years.