Parasitism, condition and number of front head breeding tubercles in roach (Rutilus rutilus L.) |
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| Authors: | R Kortet J Taskinen† |
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| Institution: | Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, FIN-40014, Finland |
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| Abstract: | Abstract – In a previous study on the male roach, Rutilus rutilus , we found a positive correlation between sexual ornamentation, breeding tubercles (BTs) on lateral sides and parasite resistance. As a continuation of that study, we examined another measure of sexual ornamentation – number of BTs on front head – of male roach from five populations. BTs on head correlated positively with fish size in two populations and with condition in one population, but not with parasite resistance (proportion of dead parasites) in any of the populations. Moreover, head BTs correlated negatively with the number of two parasite species ( Rhipidocotyle campanula and Myxobolus mülleri ) in two populations, but positively with the number of a third parasite ( Raphidascarus acus ) in one population. In addition, a negative correlation with spleen size was found in one population. The present results suggest that head BTs of male roach – although the patterns vary between populations – may signal condition and parasite load, but not resistance, in contrast to lateral BTs. Therefore, our results are in line with the hypothesis of multiple-message sexual ornaments. |
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| Keywords: | sexual selection expression of secondary sexual characters condition multiple ornaments parasitism |
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