Eyprepocmmis alacris alacris (Servffle)-biology and functional morphology of the foregut in relation to feeding (Orthoptera: Acrididae)

Abstract

Biological studies on Eyprepocnemis alacris alacris (Serville) confirm the existence of only five instars unlike as in the allied species Eyprepocnemis capitata (Miller) and two subspecies of Eyprepocnemis plorans (Chorp.), viz., E. plorans meridionalis Uvarov and E. plorans ornatipus (Walker) in which six, seven or eight instar cycles are evident. The number of instars of Eyprepocnemis alacris alacris is always constant, being five in both sexes as against seven in males and eight in females of E. plorans meridionalis. Ovipositional behaviour of E. alacris alacris involves probing and selection of oviposition site, usually ass.ociated with damp soil with tender grass having less silica content, very essential for the early ins tars.. Eggs with reticulate chorionic sculpture arranged in rows are always laid in pod s, the eggs being confined only to the bottom third, while a foamy secretion fills up the rest of the pod, including the spaces between the eggs. The incubation period is 17-18 days, the post-embryonic development lasting 105-115 days for females and 95-115 days for males. Changes involved in the foregut armature during postembryonic development correlated with the degree of silica content of grasses have been discussed.