Observations on the physiology and phylogeny of colour change in marine and freshwater leeches (Annelida: Hirudinea)

✍ Scribed by Roy T. Sawyer; Kay Dierst-Davies

• Publisher: Springer
• Year: 1974
• Tongue: English
• Weight: 1009 KB
• Volume: 44
• Category: Article
• ISSN: 1573-5141
• DOI: 10.1007/bf00187271

✦ Synopsis

An investigation of some factors which influence physiological colour changes in 16 species of freshwater and marine leeches, representing the four major families, was carried out . The emphasis was on the freshwater glossiphoniid Theromyzon tessulatum (0. F . MULLER,1774) and on the marine piscicolid Calliobdella carolinensis SAWYER & CHAMBERLAIN, 1972 . The individual chromatophores were assessed using the HOGBEN & SLOME (1931) chromatophore index . Light has a profound effect on colour change in some leeches . They darken in the light and lighten in the dark . Leeches do not adapt to background . Temperature plays only a minor role in the colour change process in leeches . Its effect may differ from species to species . The colour change response normally takes about 15-30 minutes or longer. A series of ligation and ventral nerve cord transection experiments, primarily on C . carolinensis, demonstrates that the nervous system is intimately involved in the colour change process in at least some leeches . Participation by the nervous system in the colour change response is probably via a neurohumoral mechanism . In the Hirudinea physiological colour change occurs only in certain species of the Piscicolidae and the Glossiphoniidae . Physiological colour change probably evolved de novo in the rhynchobdellid leeches .