neil

The outer-wing coverings (tegmina) of the Snub-nosed Katydid (Mastigaphoides sp.) are remarkably leaf-like, even to the extent of the centrally prominent vein and subordinate branches. They blend splendidly within rainforest foliage and are found most easily at night, after summer rains, when singing.

Such a marvellous design, but to what extent do we over-interpret the convergence of design with the character of that which provides the design-benefit, as an expression of either evolutionary adaptation or just as readily by the gracious glory of God?

I must confess that neither explanation deepens my understanding of the process that leads to mimicry and both are ever-increasingly incredible, when it is implicit that the outcome is pre-ordained.

Or is it? Perhaps the mimicry only seems to be pre-ordained; an inadvertent piece of genetic good fortune that resonates with competitiveness.

Of course there is coincidence, when two or more separate evolutionary trails randomly converge, to which we often over-attribute an awesome unlikelihood. But perhaps there is less freedom than we might imagine.

For instance, to what extent do genetic variations and mutations remain constrained by internal chemical mechanisms? Do these constraints dramatically reduce the possibility of outcomes to those that have previously overcome similar competitive hardships? And what of the prescriptive inducements of external chemical overtures; pheromones, for example, wafting across the sensitivities of a menagerie of adaptable interests?

Other examples of mimicry have been previously considered at The evolutionary power of persuasion, Unidentified (Spider) and Lichen Spiders.

If this spectacular moth had a common name it would almost certainly be the Night Citrus Swallowtail. Previously known as Nyctalemon patroclus, it has since been re-affirmed as the formerly identified Lyssa macleayi.

The compound eyes of many insect species have an effective tapetum (reflective carpet) producing strong eye shine under illumination. Light that enters the eye is only partially absorbed and that which escapes is reflected off the tapetum so that it has another chance of being absorbed. A portion of this reflected light leaves the eye again as eye-shine.

The moth is large (full hand size) and stunning in its velvety-brown and white dorsal aspect, but I do like the photograph above and particularly the way that the eyes have captured the flash of the camera.

Interestingly, the moth positions itself at rest during the day upside-down; presumably to encourage any unfortunate avian predation to the less critical end of the moth, with the ‘swallowtails’ resembling antennae.

Lichen Spiders (Pandercetes gracilis) blend superbly with the surface characteristics of their tree. They remain strategically hidden from predatory birds and simultaneously well-positioned to ambush unsuspecting insects. Poorly disguised individuals are readily picked-off and the gene pool is progressively refined.

The close-up image (above) shows the orientation of the eight eyes; four looking down the surface of the tree, two looking back up the tree and two looking outward.

I do wonder to what extent individuals are capable of modifying their appearance to suit the tree? Likewise, to what extent are trees of suitable character chosen for their conformity with the appearance of the spider? I do know that egg-sacs are disguised by the spider through the deployment of silk of different colours, but what of the spider itself?

In the image below, a collection of lichen spiders shows an array of varied colours and patterns that suit a diversity of bark types.

Introducing the Spiny-legged Rainforest Katydid (Phricta spinosa), known colloquially as the wait-a-while cricket. It is a cryptic rainforest species with a lichen-like camouflaged colour pattern. It can grow to about 100 mm in body length.

It is mostly males that ‘sing’ through an action described as stridulation; where the ‘file’ on the underside of the left wing cover (tegmen) is rubbed against the ‘scraper’ of the opposite side. The courtship song for this species is a short, sharp zzzip.

Their antennae are exceptionally long; perhaps as much as three times the body length of the katydid. These provide specialist sensory apparatus and it is often their movement that distinguishes the animal from the stillness of neighbouring vegetation.

The auditory opening is visible in the photograph on the right foreleg at the proximal end of the tibia, but obscured on the left by the antennae.

Such is the expressed concern of National Tree Day founder John Dee. However, it is unclear whether the electrified plantation of 120 new seedlings will ensure the survival of the species from the ravages of changing climate.

Perhaps some comfort can be taken from the species’ 200-million-year evolutionary history, as interglacial warming periods have occurred throughout this lengthy period of survival.

In an ABC News article, a surprising report describes the location of the Wollemi Pines, which was found in 1994 in the Wollemi National Park, as secret and suggests that poaching and feral animals are threats from which the new seedlings will be protected through an electrified fence.

The public, however, should be able to visit this plantation, which was established to try and replicate the original colony as closely as possible.