| Animals can make adaptive adjustment of selectivity as function of their own reproductive value which may cause variation in mate choice over the course of reproduction. Previously, plenty of papers discussed the effects of body size and hierarchical status on mutual mate choice in Procambarus clarkii, while few of them paid attention to mating status as a criterion of sexual selection. P. clarkii are a species rich group of large decapods crustaceans showing a promiscuous breeding system, with both sexes copulating repeatedly. Because of the long time retention between mating and oviposition, their mating status will change accordingly. In this study, by using a Y-shaped water maze, we asked whether mated males and females can discriminate between partners of different mating status, exploring the role of mating status in mate choice and their mate preferences; then testified the mate choice of virgin males through chemical communication; and further investigated the male phobotaxis towards ovigerous females.1. P. clarkii males with mating experience discriminated between partners of the same body size but with different mating status in a Y maze. Mated males spent significant more time visiting their primary partners rather than virgin targets in the total and mean durations of visits (P< 0.05), but not in the number of visits (Two-tailed test P= 0.086, but one-tailed test P= 0.043). When there was no existence of primary partners, males randomly made mate choice between virginity and nonvirgin females. When both potential mates had mating experience, males chose primary partners and nonvirgin females indiscriminately. The results showed P. clarkii males are partly able to recognize mating status of potential mates, and further indicated that male crayfish guarantee their own paternity by mate guarding based on their borrowing behavior. However, males may regulate their loyalty to primary partners whether they exist or not. In conclusion, males are able to dynamically adjust mate choice based on their own mating history and costs of mate-getting.2. P. clarkii females with mating experience discriminated between partners of the same body size but with different mating status in a Y maze. When faced with primary partners, virgin or unfamiliar mated males and a blank control, females showed significantly preferences for males in terms of the total duration of visits (P< 0.05), while they did not differentiate mating status of potential mates (P> 0.05). The results showed that females may mate as frequently as possibly out of reproductive success, while mating status may not be the female criterion of mating choice.3. Virgin males discriminated between partners of the same body size but with different mating status in a Y maze. When faced with virgin and nonvirgin females, males showed significantly preferences for virgin females in terms of the total and mean duration of visits (P= 0.01), but not in the first target visited and in the number of visits (P> 0.05).The results showed that virgin males are able to discriminate mating status of potential mates probably for the reason of reducing the risk of sperm competition. Furthermore, chemicals are predicted to mediate crayfish sexual communication.4. Adult male crayfish discriminated between ovigerous and non-ovigerous females after the breeding season in a Y maze. Among the 36 replicates, only 18 tested males made selection successfully. When faced with females in the situation of different reproductive status, males showed no preferences for either of them in terms of the first target visited, the number of visits, the total and mean duration of visits (P> 0.05). The results indicated that males indiscriminate female reproductive status during late autumn, failed to reflect the male phobotaxis when male confront aggressive ovigerous females. |
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