AGGREGATION TERRITORIES IN THE CELLULAR SLIME MOLDS

Abstract

Sporocarp size in the cellular slime molds is determined by density of the ameba prior to aggregation. This is so because the area of the aggregation territory is constant at different cell densities and therefore the number of amebae that aggregate in any one territory varies directly with the cell density. The mechanism whereby the territory size is determined is not known, although the problem of the initiation of aggregation is related to establishment of fixed territories. Since their establishment is independent of cell number we propose the hypothesis that this is also true for initiation, and that initiation is a function of space or distance. A number of conditions frame these conclusions. The territory size is characteristic for each sp. and is constant only under a given set of environmental conditions. Also the relation obviously applies only when the ameba density is sufficient for aggregation and each sp. has a specific range of densities which permit aggregation and fruiting.