The natural diet of the Notonectidae: field trials using electrophoresis

1. Field trials were conducted on populations of two sympatic species of the waterbug Notonecta (Hemiptera: Heteroptera), to examine their natural diet using the electrophoretic method of gut contents analysis.

2. Fingerprint esterase bands were identified from thirty-three potential aquatic prey types; gut contents of different instars of both species of Notonecta from the field were analysed.

3. The level of prey identification possible ranged from 73% in fifth instar N.glauca L. to 100% in third instar N.viridis Delcourt.

4. Type A errors, where no prey remains were detected from a full gut, were found in only 3% of the specimens analysed.

5. Data on gut states, the number of prey types per gut and details of aquatic prey found in the diet of different instars of field-collected Notonecta are presented.

6. These results are compared with previous data on notonectid diets, and the relative merits of different methods of diet analysis are discussed.