Natural food and feeding behavior of Culicoides furens larvae (Diptera: Ceratopogonidae).

The gut contents of Culicoides furens (Poey) larvae were compared with the relative abundance of potential food items in the natural larval habitat. Additional experiments examined the predatory behavior of the larvae by means of video recordings. Gut analyses indicated that filamentous green algae were the most frequently consumed food items. Diatoms, despite their high density in the soil, were not a major food source and many may have been ingested accidentally with algae. Gut content and video recording analyses indicated that nematodes, although occasionally eaten, probably were not the major dietary item. Moreover, fourth instars seemed to feed on nematodes more frequently during the day than during the night, possibly related to diel, small-scale vertical migrations of larvae in response to changes in light. When starved, larvae seemed to ingest nematodes more readily, as indicated by the absence of other items when nematodes were present in the gut. Overall, the results indicated that C. furens larvae are trophic generalists rather than solely predators.