INSECT INSTRUMENTALISTS ALLAKD 583 



SYNCHRONOUS CHIRPING OF CRICKETS AND KATYDIDS 



Many insects not only chirp in small groups and colonies but a 

 number of them appear inclined to bring their notes into synchronism 

 with those of their fellows. This procedure seems somewhat remark- 

 able, and some with no first-hand information worthy of serious 

 attention have been inclined to question the behavior. Synchronous 

 chirping is an undoubted fact, however, and there is no reason why 

 an insect or a bird should not in some instances perceive rhythm and 

 keep step as well as a human being. The snowy tree cricket, Oecan- 

 thus niveits, affords the best example of this behavior. B. B. Fulton, 

 who has carefully studied various races of this cricket throughout 

 its range, is as convinced as am I that this cricket prefers to chirp 

 in unison with its fellows. By an imitation of its notes I have led 

 chirping individuals to speed up their rate noticeably, in order to 

 synchronize their chirps with my mimicry. I have observed the 

 same habit of synchronous chirping in groups of the little tree cricket, 

 Cyrtoxipha gundlaclii columhiana. I happened upon one of the 

 most remarkable instances of a perfect synchronism when I met a 

 group of the cone-headed katydids, Neoconocephalus exiliscanorus, 

 rasping out their dzeet — dzeet — dzeet. From time to time one or 

 another musician would pause after the usual series of 18 to 25 

 notes. When it again joined the chorus, its notes were always per- 

 fectly timed to accompany those of the other singers. Here, for 

 long periods of time, this dropping out and taking up the musical 

 play was indulged in, but always with the same perfect synchronism 

 with its fellows. Other crickets and katydids have the habit of inter- 

 mittent stridulation, but I have never observed with them the least 

 tendency toward keeping step in the time sequences. So far as 

 I can determine, the common field cricket, Gryllus assimilis, the Euro- 

 pean house cricket, G. do7?iesficus, the jumping tree cricket, Orocharis 

 saltafor, the mole crickets, and the chirping species of Nemohms 

 show no indications of synchronous chirping. Likewise, the cone- 

 head, Neocojiocephalus ensiger, which chirps intermittently in col- 

 onies everywhere in the North shows no tendency to synchronization 

 such as I have observed so highly emphasized in the chirping behavior 

 of N. exiliscanorus. There is no reason whatever to question this be- 

 havior in creatures below man, for among the birds most remarkable 

 instances of synchronized calling and singing have been recorded 

 in the literature. There may be some simple biological or physio- 

 logical reason back of it all. In the case of the snowy tree cricket, 

 lack of thermal uniformity of the atmosphere seems to act unfavor- 

 ably upon the synchronizing impulse, for it is well known that the 

 rate of chirping of these crickets shows exceedingly nice correlations 

 with the temperature. The cold machinery of their stridulatory 



