Ci­cada Call

That's China - - Catching Cicadas 捉知了 -

Ci­cadas sing most ac­tively in hot weather and do their most spir­ited singing dur­ing the hot­ter hours of a sum­mer day, in a roughly 24 hour cy­cle. Some ci­cadas can pro­duce sounds up to 120 dB (SPL), among the loud­est of all in­sect-pro­duced sounds. This is es­pe­cially notable as their song is tech­ni­cally loud enough to cause per­ma­nent hear­ing loss in hu­mans, should the ci­cada sing just out­side the lis­tener's ear. In com­par­i­son some small species of ci­cadas pro­duce such high-pitched calls that the noise pro­duced is be­yond the hear­ing range of a hu­man. Only male ci­cadas sing in or­der to find a part­ner, but the singing of ci­cadas can vary in dif­fer­ing sit­u­a­tions. Their call is also used to ex­press alarm, and scare off or re­duce the ef­fec­tive­ness of at­tacks from preda­tors. Some species that tend to be weak fliers only sing at dusk to gain pro­tec­tion from preda­tory birds by con­fin­ing their ac­tiv­ity. Jean Henri Fabre (1823-1915), a French en­to­mol­o­gist fa­mous for his study of in­sects, ques­tioned the rea­son be­hind the drone of ci­cadas. In Fabre’s Book of In­sects, he spec­u­lates, “Whether drink­ing or mov­ing they never cease singing. It seems un­likely, there­fore, that they are call­ing their mates.You do not spend months on end call­ing to some­one who is at your el­bow. ”The in­sect en­thu­si­ast con­ducted an ex­per­i­ment where he fired two guns near the rest­ing site of mul­ti­ple singing ci­cadas. Af­ter the thun­der­ing claps of ar­tillery be­ing fired, the ci­cadas were not in the least dis­turbed and never took the time to take a break

nd in their con­certo. He con­cluded, “I think, af­ter this ex­per­i­ment, we must ad­mit that the ci­cada is hard of hear­ing, and like a deaf man, is quite un­con­scious that he is mak­ing a noise”. While the un­re­lent­ing singing of the ci­cadas can feel like an ir­ri­tat­ing record on re­peat, the tim­ing of the ci­cada’s singing can also act as a use­ful in­di­ca­tor. In the Ja­vanese ver­sion of cy­cle of months, called pranata mangsa, the ci­cada sound is used as an in­di­ca­tor of the be­gin­ning of dry sea­son (April–May). Farm­ers who still de­pend on rain ir­ri­ga­tion will in­ter­pret this as time for plant­ing of non-rice crops.

Jean Henri Fabre (1823-1915), a French en­to­mol­o­gist

Newspapers in English

Newspapers from China

© PressReader. All rights reserved.