Authors: Julianna L Johns J Andrew Roberts David L Clark George W Uetz
Publish Date: 2009/07/04
Volume: 64, Issue: 1, Pages: 13-
Abstract
Evolutionary conflicts of interest between the sexes are common as mating tactics and strategies that increase fitness benefits for one sex may incur costs for the other As a consequence antagonistic coevolution between the sexes often results in a complex arms race between male persistence and female resistance Coercive mating eg forced copulation likely benefits males by increasing the probability of mating however costs to females may be high including injury or even death Here we report on a study of the use of fangs by males of the wolf spider Schizocosa ocreata Hentz during forcible mating with resistant females which results in hemolymph loss and scar tissue formation in females Microscopic inspection revealed that fang wounds evidenced by scar tissue were absent on unmated virgin females but were found on mated females and were significantly more frequent in coercively mated females Experimental fang immobilization studies found no difference in copulation success between experimental fangs immobilized and control sham manipulation males However males that had use of their fangs had significantly longer copulation duration These findings represent a previously unknown male mating tactic in spiders and an unrecognized potential cost of mating for female spidersThis work was submitted in partial fulfillment of the requirements for completion of the degree of Master of Science in Biological Sciences at the University of Cincinnati This research was supported by the National Science Foundation IBN 0239164 to GWU and JAR IBN 0238854 to DLC the American Arachnological Society Student Research Grant to JLJ We thank the Cincinnati Nature Center for permission to collect spiders We are grateful to A Stein J Allen E Tunnat J Smith J Rovner C Kizer M Polak E Buschbeck J Rutledge E Galbraith A Lohrey B Moskalik S Gordon A Fortman and MK Uetz for assistance and support at many stages in this project We appreciate editorial comments by M SivaJothy and two anonymous reviewers
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