Models of sperm allocation predict that male mating behavior will vary with a female's reproductive condition and with information about her present and likely future status available to a male. Tests across a wide taxonomic range have shown that males allocate more sperm to previously mated females than to virgins but that in a minority of instances this allocation pattern is reversed. To investigate the basis for this discrepancy I ran sequential pairings of the crab spider Misumena vatia (Thomisidae), a species with several characteristics likely to provide insight into these conflicting results. Using duration of copulation and numbers of copulatory pedipalp movements as measures of male investment in a female, I evaluated male response to females. Males mated with a significantly higher probability, significantly longer, and produced significantly more pedipalp movements with virgin females than with previously mated females, although a minority of the subsequent males remained in copula long enough with nonvirgins for insemination to occur. Females mated with a second male at a higher probability than a third one, but length of genital contact did not differ between matings with second and third males. In this species with high first male sperm precedence, large sperm contributions to virgins enhance the possibility that they could replace a lost initial brood. The low availability of virgin females in this population may select for males that provide these females with extremely large sperm contributions, thus preventing the males from remating quickly. Copyright 2010, Oxford University Press.