Threat-sensitive behavioral trade-offs allow prey animals to balance the conflicting demands of successful predator detection and avoidance and a suite of fitness-related activities such as forag- ing, mating, and ter...Threat-sensitive behavioral trade-offs allow prey animals to balance the conflicting demands of successful predator detection and avoidance and a suite of fitness-related activities such as forag- ing, mating, and territorial defense. Here, we test the hypothesis that background predation level and reproductive status interact to determine the form and intensity of threat-sensitive behavioral decisions of wild-caught female Trinidadian guppies Poecilia reticulata. Gravid and nongravid gup- pies collected from high- and low-predation pressure populations were exposed to serial dilutions of conspecific chemical alarm cues. Our results demonstrate that there was ＇no effect of reproduct- ive status on the response of females originating from a low-predation population, with both gravid and nongravid guppies exhibiting strong anti-predator responses to the lowest concentration of alarm cues tested. Increasing cue concentrations did not result in increases in response intensity. Conversely, we found a significant effect of reproductive status among guppies from a high- predation population. Nongravid females from the high-predation population exhibited a strong graded （proportional） response to increasing concentrations of alarm cue. Gravid females from the same high-predation population, however, shifted to a nongraded response. Together, these re- sults demonstrate that accrued reproductive assets influence the threat-sensitive behavioral deci- sions of prey, but only under conditions of high-ambient predation risk.展开更多
文摘Threat-sensitive behavioral trade-offs allow prey animals to balance the conflicting demands of successful predator detection and avoidance and a suite of fitness-related activities such as forag- ing, mating, and territorial defense. Here, we test the hypothesis that background predation level and reproductive status interact to determine the form and intensity of threat-sensitive behavioral decisions of wild-caught female Trinidadian guppies Poecilia reticulata. Gravid and nongravid gup- pies collected from high- and low-predation pressure populations were exposed to serial dilutions of conspecific chemical alarm cues. Our results demonstrate that there was ＇no effect of reproduct- ive status on the response of females originating from a low-predation population, with both gravid and nongravid guppies exhibiting strong anti-predator responses to the lowest concentration of alarm cues tested. Increasing cue concentrations did not result in increases in response intensity. Conversely, we found a significant effect of reproductive status among guppies from a high- predation population. Nongravid females from the high-predation population exhibited a strong graded （proportional） response to increasing concentrations of alarm cue. Gravid females from the same high-predation population, however, shifted to a nongraded response. Together, these re- sults demonstrate that accrued reproductive assets influence the threat-sensitive behavioral deci- sions of prey, but only under conditions of high-ambient predation risk.
