In a first of its kind study in Mumbai, a group of researchers have identified five species of cicada insects from Aarey Milk Colony, yet again showcasing the biodiversity it holds.
Cicadas are mostly oval-shaped flying insects known for creating a loud noise, often also known as ‘symphony of cicadas’ in the forest during the summers. The songs are peculiar acoustic signals to attract females for mating.
The study, whose aim is to understand the species distribution in Mumbai, threats to their population, and also to create awareness as well as interest about these insects, is part of the larger Aarey biodiversity project being carried out by an Andheri-based researcher Rajesh Sanap.
“It was while gathering data inside Aarey for my project that I heard the cicadas singing and out of interest I began recording their sounds. I realised that their songs varied and on further reading, I found that every species produces different kind of sounds, which made me curious,” said Sanap who immediately contacted Kiran Marathe, a research fellow from National Centre for Biological Sciences (NCBS), Benagluru. Marathe is studying cicada’s across India.
Along with Marathe, another researcher Anuradha Joglekar, and Sanap initiated the study throughout 2017, gathering photographic evidences, their distinct calls, and matching them with the data already collected by Marathe from other places. The team was able to identify five species with the help of this data. However, work of identification of one more species is still underway.
“I have been studying cicadas in different parts of the country, including the Western Ghats and was surprised to see such rich biodiversity, that too in a small urban area at Aarey. We have identified five species here in one year and there could be even more. Their presence in large numbers also means a good presence of birds and reptiles that prey on the cicadas,” said Marathe adding that this clearly indicates that Aarey Colony needs to be conserved at any cost.
The team is also identifying threats to their population in Aarey. “Deforestation, soil erosion, urbanization, and habitat loss are potential threats to these insects. A major concern is also that the reproduction of cicadas might get affected due to the increasing ambient noise caused by urbanisation as their songs to attract females would get lost,” said Joglekar.
As part of creating awareness, the team recently released a small video giving out important information in the cicadas of Aarey, along with different songs of different species. “The cicadas have long remained the most neglected and most poorly studied insects and such citizens' science projects will play crucial role in helping generate important data that can be used by any researcher in the future,” Sanap added.
MORE ABOUT CIRCADAS
Life cycle: Comprises three stages—egg stage, nymph stage, and a short adult stage. Females lay eggs on tree barks. Upon hatching, the larvae drop to the ground where they complete the nymphal stage and then the nymphs crawl above the ground and molt into the adults.
The unique membranous structures on the sides of their abdomens, called tymbals, enable cicadas to produce calls, which are species specific.
The life-span of adult males is very short, and most individuals die immediately after mating.
In folklore, cicadas are depicted as symbols of carefree living and immortality.
