Javanese grasshopper

Appearance

There is considerable sexual dimorphism in this species with the males measuring 45 to 55 millimetres in length and the females 15 to 75 mm. The adults are yellowish-brown, yellowish or green with bluish-black markings. The hind wings, which are visible in flight, are rose red. The nymphs are pale green with dark markings.

Naming

There are about eighteen subspecies, most of which are endemic to different island groups.

Distribution

The Javanese grasshopper is native to southern Thailand, Malaysia, Indonesia and the Philippines. It is mainly a woodland species and is found in forest clearings, on trees and shrubs. It can be a serious pest in oil palm and rubber plantations.

Behavior

The life cycle of the Javanese grasshopper varies in different parts of its range, but in general, there is a single generation of insects each year. Up to four egg pods are laid in moist soil in forest clearings. When the eggs hatch, the nymphs pass through six or seven instar stages before becoming winged adults. Both nymphs and adults are diurnal and like to bask in the sun. They feed on tree foliage.

In Java the eggs remain dormant throughout the dry season and take six to eight months to hatch. After the nymphal stages they become immature adults which soon mature and start breeding. In Thailand, the eggs hatch after about two months, the nymphs grow during the wet season and remain as immature adults during the dry season. In west Malaysia there are two peak egg-laying periods, December/January and June/July, which suggests there are two physiological races present.