Orthoptera

Orthoptera (meaning ‘straight winged’) is an insect order which includes grasshoppers, crickets, katydids and relatives. This huge group makes up a significant biomass of terrestrial fauna. In the ecosystem they play a crucial herbivory role (although certain species are omnivorous or even carnivorous) as well as prey items for all sorts of predators from spiders to birds and lizards.

Conocephalus longipennis (female) feeding on grass seeds

Hexacentrus unicolor (nymph) feeding on an insect

Orthoptera is poorly studied in Singapore. The last person to do any significant work on them is Prof. Murphy 10-20 years back. Being less colourful and charismatic compared to other insects like butterflies or dragonflies, orthoptera has not attracted the attention of local nature enthusiasts. But not anymore as Tan Ming Kai, a young, mostly self trained orthopterist has started to make important progress in this field. When young, I used to catch small grasshoppers and rear them in small plastic tanks but mostly unsuccessfully. Now thanks to Ming Kai, I was able to look at them in a new light.

Around 100 species has been recorded in Singapore from surveys in the past months. Several species looks the same and so not easy to identify. It does takes lots of practices in the field before I can even identify the more common species. Some features like shape of the head, length of antennae and slight difference in body patterns can be diagnostic. Females usually have very long ovipositor at the rear end for egg-laying into the soil or plant materials.

Ducetia japonica

Eneropterinae (Gryllidae)


Tagasta marginella

Conocephalus melaenus (female)

Even though most species are uniformly green or brownish, there are some with really nice colours and patterns.

Traulia azureipennis

Xenacatantops humilis (nymph)

Nisitrus vittatus

Certain species are superb at camouflage, mainly trying to be like leaves. For example, Chondroderella borneensis will open its wings onto a leaf to flatten its profile thus becoming almost invisible. Simply amazing!

Systella rafflesii

Chondroderella borneensis

And as insects do, orthoptera go through a series of moult before reaching adulthood. Normally there are four to six nymph instars stages before adult. One way to recognise a nymph is their developing wings point downwards whereas adults’ wings point either upwards or backwards.

Conocephalus melaenus moulting

Among orthoptera, crickets and katydids are the most vocal. Their calls and songs serenade as one takes a night walk in the forest or grassland. The vocalisations are produced by means of stridulation where they rub their hind legs against the forewings or rubbing one wing against the other.

Mecopoda elongata

Local orthoptera research has been given a new lease of life by Ming Kai. There is already one scale cricket species described from Singapore by a foreign researcher but now a local guy studying local orthopteras are poised to describe other new species from here. This humble, largely ignored insect group is facing an exciting new dawn.

Larnaca species (Gryllacrididae)

Pictures and video taken at: Central Catchment Nature Reserve, September 2010, November 2010, December 2010 ; Dairy Farm, October 2010; Kranji Marshes, June 2010, August 2010.



References:

Ingrisch, S., 2006. New taxa and notes on some previously described species of scaly crickets from South East Asia. (Orthoptera, Grylloidea, Mogoplistidae, Mogoplistinae). Revue Suisse de Zoologie, 113(1): 133–227.

Tan, M. K., 2010. Orthoptera of the vacant lots in Bedok South. Nature in Singapore, 3: 69–81.

Tan, M. K., 2010. Orthoptera in Pulau Ubin. Nature in Singapore, 3: 245–268.