NYMPHAL FEEDING HABITS OF SIPHONOPERLA TORRENTIUM (PLECOPTERA, CHLOROPERLIDAE) FROM NORTH-WESTERN SPAIN

摘要

The nymphal feeding of Siphonoperla torrentium (Pictet, 1842) in Galicia (NW Iberian Peninsula) is studied. The main diet component is CPOM (approximately 33.5 % of the gut content), followed by animal prey, detritus, fungi and pollen. Chironomidae was the main ingested prey. Particularly outstanding is the importance of pollen in the feeding of these nymphs. Ontogenetic shift in the diet is detected only for prey, with animal matter being more important in the largest nymphs. Thus, the nymph of S. torrentium in the study area can be catalogued as mainly shredder and, especially when older, as predator. Obtained data are compared with those previously known for this species in other areas, showing that different populations of the same species can present different diets and they can even be catalogued in different functional feeding groups.