Copepoda Harpacticoida: Biology (Feeding)

Potential food sources of harpacticoids are organic matter and detritus (or more probably the decomposer organisms, such as bacteria, associated with detritus), other small autotrophic and heterotrophic organisms such as microalgae and ciliates, dissolved organic matter and specialized energy sources such as mucus and other extracellular polymer secretions. Direct carnivory of metazoan organisms is relatively unknown amongst harpacticoids but utilisatin of any particular food source is difficult to deduce from the morphology of the feeding apparatus, except for filter feeding in Longipediidae and Canuellidae and mucus trap feeding in the Leptasticidae. Most other harpacticoids are regarded as surface feeders and it has been suggested that, amongst these, food resources may be portioned by adaptations for feeding on different types and shapes of surfaces: a) selective epistrate feeders; b) edge scrapers; c) plane-sweepers and sand-filers and d) solid feeders. In addition, some harpacticoids are known to be able to cultivate or concentrate suitable food organisms either by producing mucus which acts as a growth substrate for bacteria or through commensal associations with other organisms such as mollusks and Crustacea. A few harpacticoids have very specialized food sources, such as the medullary tissue of red algae utilized by frond-mining species in the Thalestridae.