Dictyostelid Cellular Slime Molds from Hawai'i

Abstract

Soil and litter samples, collected from Hawai'i on the islands of Hawai'i, O'ahu, and Kaua'i, were examined for occurrence and distribution of dictyostelid cellular slime molds. In total, 194 samples, from 20 different sites and representing several plant communities, were collected during June 1995 and processed in the laboratory soon thereafter. A total of 10 species and one variety was recovered, seven of which have not been reported previously from Hawai'i. The greatest species richness (seven) and highest densities (up to 63 clones per gram of fresh soil/litter) were found on the island of Hawai'i, with lower values obtained for sites on O'ahu and Kaua'i. It was rare for dietyostelids to be recovered from more than 30% of the samples collected at any given site. A number of sites were characterized by recovery of a single species, and at least one site on each island sampled was devoid of recoverable dictyostelids. Overall, dictyostelid densities were quite low compared with those at other locations in subtropical and temperate regions of the Northern Hemisphere, and the values for species richness are lower than those reported for most neotropical mainland locations. These observations suggest a rather modest dictyostelid community in Hawai'i, at least during the relatively dry period when sampling was carried out. Lack of a windborne dispersal mechanism may be responsible for the limited distribution of dictyostelids in Hawai'i and possibly other island groups that are remote from continental land masses.