Nutrient absorption by the anal vesicle of the braconid wasp, Microplitis croceipes

Abstract

The function of the anal vesicle of Microplitis croceipes in nutrient absorption was investigated. When larvae were incubated in low-concentrations of several 14C-labeled nutrient solutions, 14C-trehalose, -glucose and -amino acids accumulated in the body of control and head-ligated larvae but failed to accumulate in larvae with the anal vesicle ligated. When larvae were incubated in a more concentrated solution of trehalose, 14C-trehalose also accumulated in the body of control and head-ligated larvae and accumulation of trehalose was reduced in the body of anal-vesicle-ligated larvae. The results indicate that the anal vesicle functions in the absorption of trehalose, glucose and amino acids. Trehalose, when present in high concentrations, was also absorbed cutaneously to some extent. The lipid, triolein, appeared to be absorbed cutaneously and absorption was unaffected by vesicle ligation. The present study also indicates that disaccharides may be absorbed as disaccharides and rapidly converted to insoluble products in the parasitoid larvae.