Mating peppermint stick

Published on: 12/12/18

Phantastic Phantom Phasmid in Daintree RainPhorest

Peppermint stick insects

Here is a very unusual stick insect, a phantastic phasmid, in fact. Phasmid means phantom or ghost. and Phasmid is the name given to the family of Stick Insects.

If you disturb it, you’ll cop a squirt of a surprisingly sweet-smelling spray of white gooey peppermint. Just enough to sting the eyes of the preying spider or bird, or surprise the over-curious tourist. But, please don’t do it. Too many “predators” can stress the little beastie.

And its colour is amazing. There’s no insect –or insect colour– quite like it. It’s young are a blueish-green, growing into a perfectly camouflaged green as it matures.
This Phasmid insect called the Peppermint Stick insect (Megacrania batesii).

Peppermints live mainly north of the Daintree River and this is where you’re most likely to see them. Small populations south of Cairns have been reported, and it seems the same species is also in New Guinea and the Solomon Islands.

Peppermints are always associated with a particular diet – the serrated leafed pandanus plant, in which it also hides skilfully on the inside barrel of the spiky leaf.

Mostly, it feeds on the screw pandanus (pandanus spiralis), although I’ve also seen them among the pandanus (Pandanus monticola) at Marrja Botanical Walk, off Cape Tribulation Road, so it’s likely that they’ll feed on some other pandanus.

Peppermints are diurnal (daytime), are very alert and have sharp eyesight. When approached, they’ll often quickly slide down backwards like a firefighter down a pole, to shelter among the spikey leaf edges.

A photo here shows a couple mating. Although, in many cases, researchers have noted that they’re not always mating when apparently joined. So, look closely! Often, the male seems just to be hitching a ride, a piggyback indeed. Presumably, this “blocking” behaviour is to safeguard his gene pool!! No competitors wanted around here!

Even when they are inextricably entwined, like the coupling two in the accompanying photo, they are almost perfectly camouflaged among the pandanus leaves.

Note the brown adult wings. The male is much smaller than the female with a better wing to size ratio. Basically this means that he can fly to other locations, and she can’t. Usually, she just drops the fertilised eggs down the leaf, and they hatch a few months later.

Males will occasionally forage too far from the females without mating. And here’s where a very special process enters the picture. The unfertilised eggs of many stick insects can still produce viable young – but they will all be female! This can continue for more than one generation, until the genders are re-united. Populations of female peppermint stick insects only have been reported south of Cairns!

This cute process is called parthenogenesis, or literally virgin birth. Many insect species actually have it, from ants to bees. All-female species have also been documented in fish, amphibians, reptiles and birds. But not yet mammals.

When I think of insects in the Daintree, I think of the Insect Museum. It’s just off Turpentine Road, 30 minutes drive from the Daintree Ferry Crossing.

The Insect Museum is a great family visit. You’ll also see spiny leaf insects, Goliath Stick Insects and, if you’re lucky, a caterpillar of the Giant Hercules Moth. Under glass are wonderful world butterflies, bugs and beetles, and some of the owner’s unique artwork.

Apart from Turpentine Road, where else can you find the Peppermint Stick Insect?

The tree and bush-types Pandanus grow in many places, especially swamp land. Peppermints seem to like the slightly cooler spots around the beaches. Look for the pandanus, preferably a low-growing one to get a good vantage point, as they hide in and slide down the leaves. Look for the telltale signs of pandanus leaves have been freshly eaten. Peppermints are diurnal, but they often escape the heat by sliding down into the base, and they seem to semi-hibernate in winter.

The Kulki (at Cape Tribulation) boardwalk up to the lookout has small, young pandanus and is the most likely spot to find them in nature. Marrja and Dubuji Boardwalk and at Myall Beach through the Cape Trib Campground are also good spots.

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