Migration in Dictyostelium polycephalum

Abstract

By comparing two species of cellular slime molds that have stalkless migration stages it is possible to gain interesting insights into how the cells move. In contrast to the familiar behavior of Dictyostelium discoideum, Dictyostelium polycephalum slugs can travel greater distances through soil and even can migrate through agar. In addition to the interest in the differences, these differences shed light on the mechanism of slug movement. Unlike D. discoideum, D. polycephalum does not have prestalk and prespore zones and severed sections of any part of these slugs move at a rate proportional to their length. This leads to the hypothesis that longer slugs move faster because the amoebae aligned along the inside of the slime sheath each contribute a forward push and the more extended the amoebae line is the faster the slug moves.

• cellular slime mold
• slug movement
• soil ecology

I thank these individuals for reading drafts and making most helpful comments: E.C. Cox, T.G. Doak, K. Inouye, D.S. Lamont, V. Nanjundiah and S. Sawai. Some fruitful discussions were had with I. Cousins and D. Grunbaum. I also thank Ling Guo for technical assistance. I am particularly indebted to Tom Doak for his generosity in helping me with experiments in the laboratory and for many helpful discussions.