The form and function of the oesophageal region of the insect parasite Tetradonema plicans (Nematoda: Tetradonematidae)

Abstract

The tetrad and companion cells, in association with the oesophagus and dorsal tract of tissue, of Tetradonema plicans, have been investigated in the host Bradysia paupera. The companion cells contain glycogen and mucopolysaccharide. The tetrad cells are rich in RNA and probably synthesize protein and secrete some as enzymes. The gut is functional and the oesophagus is in connexion with the tetrad. The dorsal tract is not connected with the oesophagus or tetrad and contains lipid with characteristics similar to that found in the eggs.It is suggested that the tetrad and companion cells are homologous with the stichocytes present in the Trichuroidea and some members of the Mermithoidea.I am grateful to Professor T. R. E. Southwood in whose department this work was carried out. I should like to thank Dr N. A. Croll for supervising and encouraging this work and Dr T. Jenkins for his helpful criticism and advice. The work was supported by the Agricultural Research Council.