Harmless screamers

Why are cicadas so loud and what is known about those dwelling in S'pore?

- Ang Qing

In temperate parts of the world, the song of the cicadas often signals the arrival of summer when the warming earth triggers their emergence.

In tropical Singapore, however, the environmental cues behind their appearance are less understood.

On March 1, a task force was launched in Tampines Changkat to study such patterns for one cicada species that has mysteriously appeared in annual swarms from around 2019, in a bid to quell their numbers.

The Straits Times explains why cicadas are so loud, and what is known about those that dwell here.

The Republic has recorded at least 11 species of cicadas, with the latest being the orange-winged cicada (Platypleura fulvigera) behind the Tampines Changkat swarms.

The insects have a range of colours from the jade green cicada to the black and scarlet cicada.

HOW LONG DO CICADAS LIVE?

Cicadas spend most of their life underground. They do not bite or sting.

Adult female cicadas lay their eggs in tree branches using their needle-like ovipositors. These eggs can take about three to six weeks to hatch, depending on the species.

The nymphs then fall to the ground and spend their life under the soil, feeding on sap from tree roots. As they burrow into the ground, they aerate the soil, helping trees grow better.

When the nymphs are ready to turn into adults, they emerge from the ground. Some species do so annually, while others can take a longer time to develop underground.