Crustacea - Feeding and Digestion in Arthropods
Branchiopods (Anacostraca) give a good instance for filter feeding mechanism. The appendages are of foliaceous type (leaf-like) called phyllopodia and they can beat metachronally. The inner edge of these appendages bears a series of endites, the most basal endite being larger as compared to the others. The backwardly directed endites bear large setae that are as well backwardly directed. The outer edge of the limb has several lobes. The most distal of these lobes is the exopodite when the basal ones are epipodite and protopodite. The limbs carry out different functions. They are locomotory, feeding and because of their delicate structure can also function like respiratory organs. The beating of limbs produces currents in surrounding water and brings in the food particles. In between the limbs present on one side, there is an inter limb space. The food materials are trapped on to the setae of endites that act as the filtering elements of the food capturing mechanism. The filtered food materials are taken to the mouth.
Copepods such as Calanus resort to maxillary filter feeding. In these organisms feeding current is made by a swimming vortex. The maxillary setae act as a filter and collect the food when the water passes by them. The setae on maxillular endites and maxillipeds eliminate the food from the maxillary setae and pass it onto the mouth.