In Copyright http://rightsstatements.org/page/InC/1.0/?language=en 'I was excited to train, so I didn't have problems with the coach' : dual career athletes' experiences of (dis)empowering motivational climates
The question whether a stress event can have a long-lasting effect on susceptibility to parasites was studied using a freshwater bivalve clam and its crustacean parasite as a model system. Anodonta piscinalis clams were collected from 2 populations during August-September 2002. Clams were transported to the laboratory and marked. The stressed clams were subjected to low oxygen for 25 days, while the unstressed control clams were caged in their lakes of origin for the same period. Then the clams were transported to a third lake where they were exposed to natural infections by the ergasilid copepod, Paraergasilus rylovi, 11 months after the stress event. The stressed clams were more intensively parasitized. They also showed lower growth, lower reproduction and lower survival than the unstressed control clams. The results indicate that susceptibility of A. piscinalis to P. rylovi infection may be condition dependent, and that stress may have a long-lasting, increasing effect on host susceptibility to parasitism in natural populations.
Several studies on vertebrates have demonstrated that reproductive activities may increase the parasite load, but this has not been shown in invertebrate hosts. We studied abundance of a potentially harmful gill parasite, the ergasilid copepod Paraergasilus rylovi, from the freshwater bivalve host Anodonta piscinalis in relation to reproductive maturity of the host in the field. Prevalence of this previously unstudied parasite varied from 90 to 100%, and the mean parasite abundance from 16.3 to 28.8 among 3 study populations. Abundance of P. rylovi increased with host size. In the maturating age groups (3-5 yr) the length-adjusted mean parasite abundance among mature, reproducing female clams that brooded glochidia larvae was 2 times higher than in nonreproducing females, the observed pattern being consistent among the 3 study lakes. Alternative, mutually nonexclusive explanations may be found for the result. For example, changes in clam behavior or filtration activity accompanying maturation can increase host exposure to parasites, or reproduction may decrease energy available to host immunologic defense. However, the present result indicates that maturation, and reproduction, is associated with increased parasite abundance in A. piscinalis, an invertebrate host.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.