The four-legged Katydid

The katydid, which has been living on the Correa for at least a month, is not the most dynamic of insects, but its almost motionless disposition does allow for close photographic scrutiny. As mentioned below, in the daytime it stands, head downwards, on a leaf; in the evenings this mostly nocturnal species ventures 7cm to the top of the Correa. I know it is capable of fast movement because during the sudden onset of torrential rain and hail last weekend it moved quickly to underneath the leaf.

Every day I check its whereabouts and because it is so well camouflaged this can take a while. A few weeks ago I thought I’d lost my little friend, but it had moved from its hitherto favourite resting spot to a lower leaf.

Today I thought the worst had happened but eventually, late in the afternoon, I found her (him) well hidden in the middle of the bush.

Something traumatic occurred last night and the katydid no longer has six legs.

One of the defense strategies of orthopterans (grasshoppers and crickets) is their ability to sacrifice a limb that's grasped by a predator by contracting a special muscle at the base of the limb. A small diaphram immediately closes the wound to prevent infection or blood loss.

Katydid (Caedicia simplex)

On April 22nd a katydid nymph (Caedicia simplex) was spotted in a Correa lawrenciana (native fuschia) near the front door. Most insects have become inactive since the onset of cooler weather, so the cold-tolerant katydid has been the subject of close photographic scrutiny.

Unlike their terrestrial relatives, the grasshoppers, katydids spend most of their time in trees or shrubs. As they ingest material from their food plant their colours develop to match the plant on which they feed and rest.

The peregrinations of this particular katydid nymph are fairly limited. Some evenings it ventures 7 cm to the top of the Correa, but most of the time it stands, head downwards, on a leaf.

There was a moment of high excitement on May 3rd when it shed its exoskeleton! Nymphs (depending on the species) take weeks or months to reach full size and will shed their exoskeletons several times while they grow. Eventually wing buds, then wings, develop. I'm expecting that an adult, fully winged katydid will venture further than the Correa...

Male katydids ‘sing’ to attract females; they stridulate by rubbing together specialized veins on their wings. The vigour of their singing is dependent on temperature. To attain the necessary thoracic temperature for stridulation male katydids (most females are silent) shiver.

A 74mm katydid species that lives in the forests of North America, Neoconocephalus robustus, must get its flight muscles to 30 degrees before it can belt out its apparently ear piercing call. The females seem to prefer the loudest (and hottest) males.

Katydids "hear" with their tympanum, a small slit in their tibia (visible in the above picture) covered by a pressure-sensitive membrane.