Katydids - Family TETTIGONIIDAE
This page contains pictures and information about Katydids that we found in the Brisbane area, Queensland, Australia.
Members in the Tettigoniidae family include Katydids, Long-horned Grasshoppers and Bush Crickets. Most of them are green in colour with leaf shaped wings that are held roof-like over the body. They have very long antenna, usually longer than their body length. Katydids have large hind legs for jumping.
Many katydids are nocturnal and rest during the day, well camouflaged on vegetation. Most of them are tree foliage feeders, they feed on leaves, flowers or seeds. A few of them are predaceous species, some are omnivorous or scavengers. Most of the katydids are resemble plants, such as leave, twigs, lichens or flowers. Nymphs are usually resemble ants, spiders or young bugs.
The common name "Katydid" is after a species whose song sounds like "Katy-did". They produce the sound by file on left wing and scraper on right. Female of some species will answer the males by different stridulation mechanisms. Some species sing in the frequency that too high for human to hear.
- Katydid's eggs, length 5mm
Females have sword-like ovipositor and lay eggs by inserted into leaf. Many species that males produce large spermathecae when courtshipping which females eat.
- nymph, body length 10mm
Most katydid species are herbivores feeding on variety of plants. Some feed only on leaves, others on flowers or fruits. A few species are predators. Many of them are active at night although some are active during the day.
Nymphs are usually very different from the adults. This allow them to live in different habitats and conditions. Some species the nymph resemble ants to avoid being eaten. Most adults camouflage as leaves.
We record the life cycle of the Gum Leaf Katydid, details please click on the link.
Classification:
- We found quite a number of different Katydid species in Brisbane. They are grouped into the followings subfamilies.
Subfamily Conocephalinae - Meadow Katydids- The Meadow katydids in Subfamily Conocephalinae are usually small and slender. They are usually found on grasses and sedges. Males chorus loudly at evening or in afternoon on overcast days and their loud buzzing calls are common in grasslands.
Subfamily Meconematine
- Swayer- The katydids in this family are usually small and greenish. They are predator to other small insects. We only found one species in this subfamily.
Subfamily
Pseudophyllinae- The first species called "katydid", Pterophylla camellifolia, was in this subfamily. This is why this subfamily called True Katydids. They can be found in tropical regions. We only found one species in this subfamily.
Subfamily Phaneropterinae - Bush Katydids- Phaneropterinae is the largest subfamily of Tettigoniidae. They can be found in different kinds of habitats. Most of them feed on a large variety of plants. Most of them are active at night although a few are active during the day. Nymphs are usually looked very different from their parents. Most nymphs take the advantages of mimicking other insects to avoid predators. Most adults, however, are green in colour and camouflage as leaf.
- There are some more Katydids yet to be identified in this page.
Katydid's front leg
- Notice the openings on its front legs, known as tympana, which is the sound receptors. They are the organs function like our ears, are to hear. The female katydid uses them to locate the males by their love songs.
Let's have a closer look of the katydid front leg. The drawing shows the foreleg of the katydid, which is the typical example of insect legs except there is the special organ tympana. The tympana is only found on katydids' and crickets' forelegs, and not on other legs nor on any legs of other insects.
All insects have three pairs of legs. These legs can be variously modified depending on the type of insect. Basically each leg has 6 segments. The coxa connects the leg to the thorax. Leading outward are the segments: trochanter, femur, tibia, and tarsus. The tarsus comprised of 3-5 very small segments. At the end of the last tiny segment is the claw. There are usually spines on the tibia. The tarsomere on the tarsus is the part in contact with the ground.
For more information on insect body parts, please see the Insect Scientific Page.
Questions for Discussion
Why it is the male katydid who made the calling, and not the female?
- Evolution theory would predict that if there were any risks involved then the sex offering the higher investment should take fewer risks. Since eggs are more expensive than sperms, the facts that the risk of detection by predators of calling individuals, males are more likely to call than females.
- Reference:
- 1. Insects of Australia, CSIRO, Division of Entomology, Melbourne University Press, 2nd Edition 1991, p382.
- 2. Grasshopper Country - the Abundant Orthopteroid Insects of Australia, D Rentz, UNSW Press, 1996.
