G. Alberti


Gerd Alberti Zoologisches Institut und Museum,
Ernst-Moritz-Arndt-Universität Greifswald,
J.-S.-Bach-Str. 11/12, 17489 Greifswald, Deutschland;


On predation in Epicriidae (Gamasida, Anactinotrichida) and finestructural details of their forelegs


The present study reveals, based on video-recording, that Epicriidae are predators using their long forelegs provided with a number of long clubbed setae for the capture of small arthropods. The mite walks slowly with raised and probing forelegs. Upon contact with a small isotomid springtail, the forelegs rapidly touch the prey with the tips of the elongated, clubbed setae. The prey evidently adheres to these setae and is drawn back to the mouthparts. The epicriid feeds for a considerable time on its prey whereby the mite can move around until it finds a shelter. The clubs represent spinose setal ends which are loaded with a granular secretion. The origin of the secretion could not yet be clarified definitely. Since the setae contain a lumen it might be that the secretion reaches the club through the seta. The secretion which covers the surface of the mite as a cerotegument is fine structurally distinctly different and is most likely produced by typical anactinotrichid dermal glands, which also occur in the forelegs. Some details of the fine structure of legs I are demonstrated. Since these clubbed setae occur in all Epicriidae it seems likely that all are predators feeding on small, weakly sclerotised arthropods.


adhesive setae, dermal glands, mites, sensory setae, video recording