Polygynous males can change their mating tactics across their lifetime, but information is scarce on the flexibility of this trait within a given season and the relative costs and benefits of using different tactics. ...Polygynous males can change their mating tactics across their lifetime, but information is scarce on the flexibility of this trait within a given season and the relative costs and benefits of using different tactics. Here, we monitored individually marked male reindeer Rangifer tarandus and classified their mating tactics as harem-defense, sneaking, or mixed. The costs of the male reproductive effort were assessed using both direct （i.e. percentage of body mass lost） and indirect measures （i.e. activity patterns such as feeding, standing, and walking）, while mating group size and reproductive success were recorded as mating ef- fort benefits. Our results show that reindeer males may switch between the harem-defense and sneaking tactics throughout the same breeding season, providing further support to the notion that reproductive tactics are flexible in ungulates. The costs and benefits of male mating effort vary according to the mating tactic, reaching the highest values in harem-holders and the lowest values in sneaking males. Moreover, males who switched between the sneaking tactic and the harem-defence tactic tended to achieve higher mating success than males who consistently used the least costly tactic. Indeed, all harem-holders successfully sired offspring, whereas only two out of three mixed-tactic males sired one calf, and sneaking males did not sire any calves. In conclusion, our results show that reindeer males can modulate their mating efforts during the same breeding season by switching between the most costly harem-defense tactic and the least costly sneaking tactic, suggesting individual solutions to the balance between reproductive effort and mating opportunities [Current Zoology 61 （5）： 802-810, 2015].展开更多
Males and females have conflicting interests on the frequency and outcomes of mating interactions.Males maximize their fitness by mating with as many females as possible,whereas choosy females often reduce receptivity...Males and females have conflicting interests on the frequency and outcomes of mating interactions.Males maximize their fitness by mating with as many females as possible,whereas choosy females often reduce receptivity following copulation.Alternative male mating tactics can be adaptive in their expression to a variety of mating contexts,including interactions with a relatively unreceptive mated female.Male Rabidosa punctulata wolf spiders can adopt distinctive mating tactics when interacting with a female,a complex courtship display,and/or a more coercive direct mount tactic that often involves grappling with females for copulation.In this study,we set up female mating treatments with initial trials and then paired mated and unmated females with males to observe both female remating frequencies and the male mating tactics used during the interactions.Males adopted different mating tactics depending on the mating status of the female they were paired with.Males were more likely to adopt a direct mount tactic with already-mated females and courtship with unmated females.Already-mated females were considerably less receptive to males during experimental trials,although they did remate 34%of the time,the majority of which were with males using a direct mount tactic.Whereas males adjusting to these contextual cues were able to gain more copulations,the observation of multiple mating in female R.punctulata introduces the potential for sperm competition.We discuss this sexual conflict in terms of the fitness consequences of these mating outcomes for both males and females.展开更多
文摘Polygynous males can change their mating tactics across their lifetime, but information is scarce on the flexibility of this trait within a given season and the relative costs and benefits of using different tactics. Here, we monitored individually marked male reindeer Rangifer tarandus and classified their mating tactics as harem-defense, sneaking, or mixed. The costs of the male reproductive effort were assessed using both direct （i.e. percentage of body mass lost） and indirect measures （i.e. activity patterns such as feeding, standing, and walking）, while mating group size and reproductive success were recorded as mating ef- fort benefits. Our results show that reindeer males may switch between the harem-defense and sneaking tactics throughout the same breeding season, providing further support to the notion that reproductive tactics are flexible in ungulates. The costs and benefits of male mating effort vary according to the mating tactic, reaching the highest values in harem-holders and the lowest values in sneaking males. Moreover, males who switched between the sneaking tactic and the harem-defence tactic tended to achieve higher mating success than males who consistently used the least costly tactic. Indeed, all harem-holders successfully sired offspring, whereas only two out of three mixed-tactic males sired one calf, and sneaking males did not sire any calves. In conclusion, our results show that reindeer males can modulate their mating efforts during the same breeding season by switching between the most costly harem-defense tactic and the least costly sneaking tactic, suggesting individual solutions to the balance between reproductive effort and mating opportunities [Current Zoology 61 （5）： 802-810, 2015].
基金This research was funded by the McPherson College Department of Natural Sciences.
文摘Males and females have conflicting interests on the frequency and outcomes of mating interactions.Males maximize their fitness by mating with as many females as possible,whereas choosy females often reduce receptivity following copulation.Alternative male mating tactics can be adaptive in their expression to a variety of mating contexts,including interactions with a relatively unreceptive mated female.Male Rabidosa punctulata wolf spiders can adopt distinctive mating tactics when interacting with a female,a complex courtship display,and/or a more coercive direct mount tactic that often involves grappling with females for copulation.In this study,we set up female mating treatments with initial trials and then paired mated and unmated females with males to observe both female remating frequencies and the male mating tactics used during the interactions.Males adopted different mating tactics depending on the mating status of the female they were paired with.Males were more likely to adopt a direct mount tactic with already-mated females and courtship with unmated females.Already-mated females were considerably less receptive to males during experimental trials,although they did remate 34%of the time,the majority of which were with males using a direct mount tactic.Whereas males adjusting to these contextual cues were able to gain more copulations,the observation of multiple mating in female R.punctulata introduces the potential for sperm competition.We discuss this sexual conflict in terms of the fitness consequences of these mating outcomes for both males and females.
