Soil algal relationships to Onychiurus folsomi, a minute arthropod

Abstract

Elucidation of the roles of the soil algae is a natural goal of the algal component study of the Island Ecosystems IRP. Thus, the present study investigated the possibility that the algae could serve as food for the 5 to 6 mm long insect, Onychiurus folsomii, the most ubiquitous of the soil arthropods in the Hawaii Volcanoes National Park. This goal was sought through a series of laboratory experiments. In some algae grown on Bold's basal medium solidified with agar it was found that 15 species of algae in unialgal culture were ingested. Some of the algal species grew after transiting the insects and perhaps their progeny were recycled. While no algae were seen in the gut of any wild insect, the algae and insects occur together. It was found, however, that in the laboratory the insects grew and reproduced more when algae were present than when on agar medium alone. Using carbon-14 marked algal cells it was demonstrated that labeled material from the algae passed out into the insect tissues increasingly with time as the cells passed through insect gut. It is concluded such soil insects as Onychiurus can grow and reproduce on algae found in their environment and may do so in nature.