The anatomy and physiology of the morabine grasshoppers I. Digestive and reproductive systems

Abstract

The grasshoppers of the subfamily Morabinae (Orthoptera: Eumastacidae) differ substantially from the better-known Acrididae in their internal anatomy. Two additional sets of diverticula are present on the gut. One set, of taxonomic interest in that some species have 12 diverticula whereas others have 18, issues from the midgut. Another set of six diverticula issues from the ileum and is brightly coloured according to the nature of the food in the gut. The gastric caeca, which in Acrididae have posterior and anterior segments, lack the posterior segment in morabines. The proventriculus differs in structure from the acridid type, having a cardiac valve of two flaps without V-shaped sclerotizations. The pyloric sphincter, however, has 12 V-shaped sclerotizations which are absent in acridids. The male accessory glands are long and generally unconvoluted. They can be classified according to appearance and function into eight distinct types. The female spermatheca is uniformly shaped throughout the Morabinae studied, but is relatively large compared with the spermatheca of acridids, and in morabines is larger than the few known spermathecae of other Eumastacidae. The number of ovarioles in each ovary is small (2-10, according to the species), and the tracheation of the internal reproductive system in both sexes differs considerably from the arrangement found in Acrididae.