INSECTICIDAL ACTIVITY A NEW BIOACTIVE PROPERTY OF THE CYANOBACTERIUM FISCHERELLA POLISH JOURNAL OF ECOLOGY

ABSTRACT: Cyanobacterial biofilms serve as food and shelter for benthic invertebrates, such as juvenile insects. Chironomids are often the most widely distributed and abundant insect lar-vae in freshwater ecosystems. As a consequence of high grazing pressure, effective defence mecha-nisms can be expected in biofilm-forming organ-isms. The presence of chemical defence was stud-ied in 12 axenic and monoxenic cyanobacterial species. Flakes of cyanobacterial biofilms were offered to Chironomus riparius (Meigen) over a period of 8 days. Mortality and body-length of the surviving animals were used as indicators for the toxicity of the cyanobacteria and their suit-ability as food. Toxicity and inhibition of larva