A new study has shown that cicadas about 100 million years ago had yet to learn to produce the iconic buzzing sound that now characterizes summer days.
Cicada, referring to the superfamily Cicadoidea, includes the globally widespread Cicadidae, commonly known as singing cicadas, and Australia-only Tettigarctidae. The former can produce the loudest sounds among insects, reaching nearly 120 decibels via tymbal mechanisms.
In the study published in Nature Communications, a team of international scientists looked at 11 pieces of Cicadoidea fossils from Myanmar with a 100-million-year history and compared them with other fossils and extant cicadas.
Although tymbal was identified in these fossils, the majority lacked intricate sound production and auditory systems, said Jiang Hui, lead author of the paper and a researcher with the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences.
"This suggests that most cicadas from 100 million years ago might have relied on more primitive means of communication -- to transmit body vibrations through substrates like tree trunks -- rather than amplifying sounds through abdominal vibrations and transmitting them through the air," said Jiang.
"In other words, they might not have sung like today's cicadas," Jiang said.
This study also reports powerful fossorial forelegs from nymphal fossils, akin to modern cicadas, suggesting similar robust capabilities for digging, subterranean long-term living, and root-feeding. (Xinhua)
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