ENVIRONMENTAL FACTORS IN INTERRUPTION 

 OF DEVELOPMENT OF ACRIDIDAE EGGS 



A. S. SHULOV AND M. P. PENER 



Laboratory for Entomology and Venomous Animals, 



Department of Zoology, Hebrew University, 



Jerusalem (Israel) 



The ways in which Acrididae eggs may develop are manifold. 

 The eggs of tropical and subtropical locusts Schistocerca 

 gregaria (Forskal) and Lociista migratoria migratorioides (R. and 

 F.) usually develop continuously and hatch within a compara- 

 tively short period. Some others also develop continuously under 

 field conditions, but there may be a slow development at lower 

 temperatures, as in the case of Pareuprepocnemis syriacus 

 (Table I). 



There are many other types of development which include 

 interruption at various stages of the embryonic development, 

 such interruptions being caused by intrinsic as well as extrinsic 

 factors, e.g. temperature and humidity or both these factors 

 combined. 



Slifer^, Steele', Bodenheimer and Shulov^ and Shulov and 

 Pener^ provided the basis for the study of embryonic develop- 

 ment in some Acrididae by describing morphological stages in 

 connection with the time of their appearance (Fig. 1). 



Shulov^ classified interruptions in embi*yonic development of 

 Acrididae according to four types. 



The first may occur in the initial period after oviposition, 

 when the Qgg is dormant and no embryonic germ-band appears 

 during a period of two to four weeks. This type of pause appears 

 in Dociostaurus maroccanus^, Austroicetes cruciata'^ and in 

 Tmethis pulchripennis asiaticus^. In Dociostaurus, the eggs during 

 this period are not influenced by temperature. The water content 

 of the eggs of Dociostaurus and Tmethis is at equilibrium or they 

 lose some water: the addition of water during this period kills 

 the eggs of both species. 



