Biochemical energy reserves of entomopathogenic nematodes

Quantitative and qualitative analyses of the biochemical energy reserves of 6 species of entomopathogenic nematodes (Rhabditida: Heterorhabditidae and Steinernematidae) were conducted. Lipid, glycogen and protein contents of 2 species of Heterorhabditis (H. bacteriophora and H. megidis) and 4 species of Steinernema (S. carpocapsae, S. feltiae, S. glaseri, and S. scapterisci) were determined. The quantitative measurement of energy reserves (32-38% lipids and 42-46% proteins) suggested that entomopathogenic nematodes are more similar to free-living nematodes than to parasitic ones in this respect. These results also elucidate relationship between activity levels and life span from an energetic perspective. Calculated energy content of these 6 entomopathogenic nematodes ranged from 0.029 to 0.123 J/infective juvenile. Fatty acid composition of nematodes was estimated. The percentage of saturated fatty acids differs among nematode species. Saturated fatty acids of S. scapterisci, a nematode isolated from a tropical region, were greater than for the other nematodes tested, condition usually associated with warm-adapted animals.