1916] 



Breeding Habits of the Orthoptera 



127 



SPECIALIZED AND SIMPLE TYPES OF REPRODUCTIVE BEHAVIOUR. 



In considering the different aspects of the reproductive 

 behaviour, (preHminary movements, oviposition, etc.), the 

 Acridida; appear to be the least speciaHzed. The Cockroaches 

 and the Mantids are speciaHzed in the habit of constructing 

 egg capsules and cocoons. The Locustidas and the GrylHd« have 

 developed their preliminary movements to a great extent and 

 also have a speciaHzed type of oviposition, but different from 

 the Cockroaches and the Mantids. The Acrididse seem to be 

 specialized in neither regard and occupy a somewhat inter- 

 mediate position as regards egg-laying and preliminary 

 movements. 



BLATTIDAE 



MANTIDAE 



PHASMIDAE 



ACRIDiDAE 



LOCUSTIOAE 



GRYLLIDAE 



-32 

 -.23 

 -17 

 -13 

 -11 

 -4 



■ 524 



194 

 -214 



64 



NUMBER OF SUB FAMILIES 



AMERICAN 



EUROPEAN 



, F'^-.,.^- Diagram to illustrate effect of specialization upon the number of 

 -sub-tamihes m each group of the Orthoptera. 



It is a well known fact that speciaHzation in any habit, 

 especially in breeding habits confines the animal to a more 

 limited field and lessens its chances for adjusting itself to 

 changes in environment. Consequently the animal which has 

 the more general habits can occupy the larger general field and 

 so have a larger representation. Figure 1 represents the total 

 number of subfamilies in each group of the Orthoptera in the 

 Holoarctic realm. The Acrididae far outnumber the other 

 groups. Locally one subfamily may predominate as it finds 

 conditions favorable to its mode of specialization; but in 

 general, non-speciaHzed conditions will prevail, and it is the 

 type of animal which has the least degree of speciaHzation that 



