Environmental stressors can negatively affect avian cognitive abilities, potentially reducing fitness, for example by altering response to predators, display to mates, or memory of locations of food. We expand on curr...Environmental stressors can negatively affect avian cognitive abilities, potentially reducing fitness, for example by altering response to predators, display to mates, or memory of locations of food. We expand on current knowledge by investigating the effects of dietary mercury, a ubiquitous en- vironmental pollutant and known neurotoxin, on avian cognition. Zebra finches Taeniopygia gut- tata were dosed for their entire lives with sub-lethal levels of mercury, at the environmentally rele- vant dose of 1.2 parts per million. In our first study, we compared the dosed birds with controls of the same age using tests of three cognitive abilities： spatial memory, inhibitory control, and color association. In the spatial memory assay, birds were tested on their ability to learn and remember the location of hidden food in their cage. The inhibitory control assay measured their ability to ig- nore visible but inaccessible food in favor of a learned behavior that provided the same reward. Finally, the color association task tested each bird＇s ability to associate a specific color with the presence of hidden food. Dietary mercury negatively affected spatial memory ability but not inhibi- tory control or color association. Our second study focused on three behavioral assays not tied to a specific skill or problem-solving： activity level, neophobia, and social dominance. Zebra finches exposed to dietary mercury throughout their lives were subordinate to, and more active than, con- trol birds. We found no evidence that mercury exposure influenced our metric of neophobia. Together, these results suggest that sub-lethal exposure to environmental mercury selectively harms neurological pathways that control different cognitive abilities, with complex effects on be- havior and fitness.展开更多
基金This work was funded by an award from the National Science Foundation [to J.P.S. and D.A.C.] （IOS1257590} and an English-Stonehouse fellowship [to J.P.S. and A.S.F.] awarded by the College of William and Mary.
文摘Environmental stressors can negatively affect avian cognitive abilities, potentially reducing fitness, for example by altering response to predators, display to mates, or memory of locations of food. We expand on current knowledge by investigating the effects of dietary mercury, a ubiquitous en- vironmental pollutant and known neurotoxin, on avian cognition. Zebra finches Taeniopygia gut- tata were dosed for their entire lives with sub-lethal levels of mercury, at the environmentally rele- vant dose of 1.2 parts per million. In our first study, we compared the dosed birds with controls of the same age using tests of three cognitive abilities： spatial memory, inhibitory control, and color association. In the spatial memory assay, birds were tested on their ability to learn and remember the location of hidden food in their cage. The inhibitory control assay measured their ability to ig- nore visible but inaccessible food in favor of a learned behavior that provided the same reward. Finally, the color association task tested each bird＇s ability to associate a specific color with the presence of hidden food. Dietary mercury negatively affected spatial memory ability but not inhibi- tory control or color association. Our second study focused on three behavioral assays not tied to a specific skill or problem-solving： activity level, neophobia, and social dominance. Zebra finches exposed to dietary mercury throughout their lives were subordinate to, and more active than, con- trol birds. We found no evidence that mercury exposure influenced our metric of neophobia. Together, these results suggest that sub-lethal exposure to environmental mercury selectively harms neurological pathways that control different cognitive abilities, with complex effects on be- havior and fitness.
