The influence of temperature on the biological activity of selected nematode species (Steinernematidae and Heterorhabditidae) under the conditions of their coexistence

Abstract

The presented study is concerned with infectivity of select entomopathogenic nematode species under different temperature conditions (15, 20 and 25 °C) in the presence of competing species. Two species of nematodes of the genus Steinernema (S. kraussei, S. feltiae) and two of the genus Heterorhabditis (H. bacteriophora and H. megidis) were included in the analysis. Different experimental variants were adopted in which the selected two entomopathogenic nematode species were mixed between Steinernema and Heterorhabditis. The study showed that Heterorhabditis and Steinernema cannot coexist together in a single host and one genus will always prevail. H. megidis, under co-occurrence with S. feltiae separately infected Galleria mellonella larvae most commonly at 15 °C, while H. bacteriophora at 20 °C. The study showed that the main determinant of nematode activity towards the host is not temperature, but the presence of co-existing nematode species. The results of the experiment encourage further research to determine the effects of a variety of concurrent biotic and abiotic factors on entomopathogenic nematodes and their biological activity.