Pathology (?) of Plagiorhynchus cylindraceus in the starling, Sturnus vulgaris.

Our field study did not support anecdotal claims alleging pathogenicity on the part of P. cylindraceus in starlings. Within-clutch analysis of nestling starling weights (n = 25) over time showed that P. cylindraceus had no effect on position in clutch relative to siblings. Parasitized nestlings tended to weigh more than control siblings. Within-sex analysis of wild adult starling weight (n = 103) showed no difference between animals with acanthocephalans and uninfected animals and weight was not related to intensity of infection. Host response to the proboscis was limited to immediately-surrounding tissue (90 microns). Other observations made in this study included the following: (1) no evidence for deleterious intraspecific interaction among adult P. cylindraceus in starlings; (2) no apparent interspecific interactions between P. cylindraceus and (unidentified) cestode species in starlings; and (3) copulatory caps on male P. cylindraceus may be a response to environmental deterioration in dead hosts.