Laying mantis

Pruning in the garden can be hazardous for the pruner’s fingers, but in this case it was the well-camouflaged inhabitant of a shrub that was in danger from the secateurs of Susan at Strath Creek. She discovered, just in time, a praying mantid that was in the process of laying eggs, or at least constructing an egg sac known as an ootheca – see photos.

The ootheca is a spongy pouch that is glued to twigs or leaves and hardens to form a protective case for up to 400 eggs, depending on the species. The female uses appendages called cerci at the end of her abdomen to spin and shape the foamy ootheca. These cerci can be seen in the photo below.

Praying mantids (order Mantodea – meaning prophet) can sometimes be confused with other insects with elongated bodies such as stick insects, mantis flies and even some grasshoppers and crickets. Distinguishing characteristics of the mantids include mobile triangular-shaped heads with large compound eyes, strong forelegs with spines for catching prey, long thin antennae and, of course, construction of an ootheca. And a fascinating fact from Michelle Gleeson’s wonderful book Miniature Lives: “Praying mantids have a specialised hearing organ between their hind legs, allowing them to detect the ultrasonic calls used by bats to locate their prey. This provides mantids with an early warning system, giving them time to flee or drop to the ground before the bat can swoop.”

We won’t attempt to identify Susan’s praying mantid as there are about 160 species in Australia, most of which belong to the family Mantidae.

Generally speaking praying mantids should be welcome in the garden because they consume a variety of insect pests, such as aphids and thrips. But Susan will have to wait a while for an increase in her mantid population, because, depending on the species, the eggs can take up to 6 months to hatch!

[Just to clarify (or confuse?): both the terms praying mantis and praying mantid seem to be widely used interchangeably, although perhaps mantis should be confined to members of the genus Mantis, one of a number of genera in the family Mantidae?]