#18 A mantid out of its territory

Praying mantids are secretive insects of the garden, adopting a motionless stick-like stance to blend into their surroundings if disturbed. They can be distinguished from grasshoppers and stick insects by their characteristic way of standing with forelegs held together as if praying.

Extremely mobile triangular head and segmented antennae

I found Orthodera gunnii, previously known as Orthodera marginata, from family Mantidae, in my garden in February of 2007. According to both The Australian Museum and CSIRO, who identified the mantid, the Hunter Valley is outside of its expected range.

It is usually found in New South Wales (Bulloo River basin, Lake Eyre Basin, Murray-Darling basin), Northern Territory (Lake Eyre Basin, N Gulf, W Plateau), Queensland (Bulloo River basin, Lake Eyre Basin, Murray-Darling basin, N Gulf, NE coastal), South Australia (Lake Eyre Basin, S Gulfs, W Plateau), Tasmania, Western Australia (NW coastal, SW coastal, W Plateau).

Most mantids are known as clumsy fliers, but this species is known to fly substancial distances, so it is not surprising to find it in the Hunter Valley, especially during times of drought.

Temporarily caught in a spider's web at night

Orthodera gunnii closely resembles the more common Othodera ministralis, the Garden or Green Praying Mantid. It is similar in size, colour and habits, with the most noticable difference being the face colouration which is green in the common Garden Mantid and mauve in Orthodera gunnii.

A mantid scurries away as I attempt to photograph it

Praying mantids are carnivorous as both adults and nymphs and eat insects, which they seize with their spiked forelegs. They have a sit-and-wait hunting strategy.

Breeding habits

Female mantids have the bizarre habit of eating the male during or after mating. The insect world can be a dangerous place.

The female lays her eggs in a foamy substance that hardens into a distinctive case, called an ootheca. These egg sacs can be attached to branches, tree trunks, logs, fences and even buildings. Below is an image of a mantid ootheca and hatchling, although it does not belong to Orthodera gunnii. I have included this picture to illustrate the general appearance of a mantid ootheca.

Mantid ootheca (egg sac) and hatchling

The hatchlings, (nymphs), emerge from the ootheca resembling small wingless adults and develop through a series of stages (instars), moulting several times before reaching maturity. Mantids are good examples of insects that have gradual metamorphosis.

As they grow, the wings develop. With each moult the wing buds increase in size. When the wings are fully developed, the mantid has become an adult. There are exceptions, however, where some adults have stunted wings or no wings at all. When young, they will eat their siblings if food is scarce.

Illustrating the face and inner front leg colouration

Underside view, while temporarily caught in a web

This has been a difficult project to research as it appears to be a little-studied species. It would make an interesting exercise to record sightings from locations around the country, so if readers have observed Orthodera gunnii in their district, I would love to hear about it.

Appearing to only have two sets of legs, the third pair are typically tucked under the head against its thorax

I found this attractive and fascinating mantid on three separate days in my backyard, and was able to observe it at length. They depend upon camouflage as defence against spiders, bats and birds. Although their large staring eyes give them a rather fearsome appearance, they are of no threat and rid the garden of many insects. If you have them in your garden, you are fortunate.