Australia:Nature's Mimics

On 5 October 2021, Australia Post issued a set of postage stamps featuring Nature's Mimics - animals that protect themselves through protective disguises.

Thousands of organisms – animal and plant, though most numerously in the insect world - employ modes of deception to extend their existence; they prolong their lives through protective and/or predatory disguises that increase their defences, their access to food and the likelihood of their successful reproduction. Part of the process of natural selection, the evolution of mimetic mechanisms confers advantage to a mimetic species in the ongoing battle for survival.

Issue Description
Mimicry is a diverse and complex set of adaptations that can be visual, perceptual and behavioural (including scent release and vocal performance). The key players in the dynamic of mimetic relationships are the “mimic”, the “model” and the “dupe”, or “receiver”, with the intent of the mimic being to alter the behaviour of the receiver through communication of signals. Most usually there is a winner and loser in the relationship, but mimicry can also be mutually beneficial to the mimic and model. For example, one species may adapt to resemble another for defensive purposes, and this, statistically, reduces the likelihood of both species being predated by a common enemy.

The stamps, illustrated by Anita Xhafer, show animals from three groups - a bird, a fish and an insect - that have evolved to use visual mimicry for protective purposes. The illustrations reveal the animal while simultaneously indicating its capacity for camouflage.

Stamps
Leafy Seadragon, Phycodurus Eques (AU$1.10)

The Leafy Seadragon (Phycodurus Eques), also known as Glauert's Seadragon, inhabits temperate waters along Australia's southern coastline, mainly from South Australia to Western Australia. It is not commonly observed due to the yellowish-brown leaf-like appendages covering its body, which provide excellent camouflage in seagrass meadows, seaweed and kelp-covered rocky environments. The appendages gently move with the current to give the seadragon an ethereal appearance. Two small pectoral fins and a single caudal fin provide propulsion, which is slow and rhythmic, accentuating the camouflage effect in mimicking the movement of seaweed. The Leafy Seadragon is also able to change its colour to correspond with its habitat. Tawny Frogmouth, Podargus Strigoides (AU$1.10)

The Tawny Frogmouth (Podargus Strigoides) is a nocturnal bird, of which there are three subspecies occurring in Australia's south-east (strigoides), central and west (brachypterus) and north (phalaenoides), the latter being noticeably smaller than the former two. Its length ranges between 34 and 53 cm. The mottled patterning of the Tawny Frogmouth's plumage aids camouflage, in giving the effect of bark and lichen of weathered trees, and its preferred habitat is eucalypt woodland.

During daylight hours, the Tawny Frogmouth will sit motionless on a tree branch, mimicking, through its elongated shape and bristled brow, a jagged broken branch. In this defensive posture, the bird will open its eyes just a slit (so as not to attract attention), its head imperceptibly following the movement of any intruder. Macleay's Spectre, Extatosoma Tiaratum (AU$2.20)

The endemic Macleay's Spectre (Extatosoma Tiaratum), also known as the Spiny Leaf Insect and the Giant Prickly Stick Insect is mainly distributed in rainforests in Queensland and New South Wales. While it mimics its habitat to camouflage itself, it will also sway, as if it is a leaf caught by the breeze, and curl its tail as if aping a scorpion when it is threatened. Some, like the individual shown on the stamp, also mimic lichen if this is particular to its environment. Because these insects are herbivorous, they use camouflage only for defensive purposes.

Macleay’s Spectre has an amazing life cycle, which is also defined by mimicry: it drops its eggs onto the ground, so that red-headed black ants, attracted by a knob on the egg, take them to their nest where they eat the knob, leaving the eggs to hatch (thus avoiding predators). The nymphs then smell and behave like red-headed black ants prior to emerging from the ground; before being sprung by the ants, the nymphs ascend the trees.

Minisheet
The Minisheet shows the Superb Lyrebird (Menura Novaehollandiae), Australia's stellar vocal mimic, able to replicate both natural and human-made sounds.

First Day Covers
The first First Day Cover is a pictorial envelope with the three gummed stamps from the Nature's Mimics stamp issue affixed and postmarked - First day of issue | 5 October 2021 | Hyde Park, QLD, 4812

Envelope size: 190mm x 110mm.

The second First Day Cover is a pictorial envelope with the Minisheet from the Nature's Mimics stamp issue affixed and postmarked - First day of issue | 5 October 2021 | Hyde Park, QLD, 4812

Envelope size: 190mm x 110mm.

Gutter Strips
Each Gutter Strip consists of ten stamps of each of the Nature's Mimics stamps (one design), five on either side of the blank strip (containing "Traffic Lights") separating the two panes of a stamp sheet.

Maxi Cards
This Maxicard set contains the three Maxicards from the Nature's Mimics stamp issue.

A Maxicard is a prepaid postcard with a stamp affixed and postmarked on the view side. The subject matter of a Maxicard is common to the card, stamp and postmark.